>_

/p

Paste

from Share & Store

Share code with syntax highlighting. Raw view, burn-after-read.

113x

[ ]

/s

Share

from Share & Store

Drop a file, get a link. Up to 100 MB. Auto-expires.

117x

###

/n

Note

from Share & Store

Write a note in Markdown with live preview, then share a link. No account needed.

76x

¶

/r

Rich Note

from Share & Store

Publish a formatted note with a visual rich-text editor. No account needed.

49x

[*]

/i

Image

from Share & Store

Upload or paste an image. Direct link, embed codes.

164x

->

/u

URL

from Share & Store

Shorten any URL. Custom slugs, click stats, optional TTL.

72x

[*]

/secret

Encrypted Secret

from Share & Store

Share a password or key, encrypted in your browser. Burn-after-read. Server never sees it.

39x

))

/drop

Local Drop

from Share & Store

Send files device-to-device on your network. Peer-to-peer, nothing stored.

68x

⧉

/clip

Clipboard Sync

from Share & Store

Send text between your devices with a 6-digit code. Relayed live, never stored.

67x

<=

/hook

Webhook Tester

from Share & Store

Get a URL that captures every request sent to it. Inspect method, headers, body live.

59x

|||

/poll

Poll

from Share & Store

Anonymous polls with live results. Single or multiple choice, no IPs stored.

64x

?=

/survey

Survey

from Share & Store

Build a multi-question survey with choice and open-text questions, share a link, and watch live results. One response per person, optional end-to-end encryption.

33x

(▭)

/screen

Screen Share

from Share & Store

Share your screen to another device on your network. Peer-to-peer, nothing uploaded.

58x

◉

/call

Video Call

from Share & Store

Quick group video + voice call over a room code. Peer-to-peer, nothing recorded.

62x

✎

/board

Shared Whiteboard

from Share & Store

Sketch together in real time over a room code. Strokes and sticky notes relayed live, never stored.

72x

◎

/geoshare

Live Location

from Share & Store

Share your live GPS location on a link. Relayed to viewers in real time, auto-expires after at most 3 days.

174x

★

/my

My Tools

from Share & Store

Star your favorite tools and build a personal home page — searchable catalogue, one tap back to what you use most.

45x

⚒

/forge

Forge

from Encode & Decode

Chain operations into a recipe — encode, hash, compress, cipher, reshape text — step by step in your browser.

104x

64

/b64

Base64 / 32 / Hex

from Encode & Decode

Encode or decode text as Base64, Base32, hex, Base58, or z85.

41x

%

/urlencode

URL Encode

from Encode & Decode

Percent-encode or decode URL components. Live sync.

63x

&

/entities

HTML Entities

from Encode & Decode

Encode or decode HTML entities. Live sync between both boxes.

26x

\n

/escape

Escape

from Encode & Decode

Escape or unescape strings for JSON, regex, and other formats.

87x

{.}

/jwt

JWT

from Encode & Decode

Decode a JWT, sign and verify with HMAC, and see its expiry timeline — iat, nbf and exp plotted live. All in your browser.

92x

[z]

/gz

Gzip / Brotli / Zstd

from Encode & Decode

Compress or decompress text with gzip, deflate, brotli, or zstandard. Shows size difference.

70x

[Z]

/zip

Zip / Tar

from Encode & Decode

Build a .zip, .tar.gz or .tar from files, or open one to list and extract its contents — all in your browser.

30x

01

/bin

Text ↔ Binary

from Encode & Decode

Convert text to and from 8-bit binary. UTF-8 bytes, space separated.

32x

↻

/rot

ROT13 / Caesar

from Encode & Decode

Apply a ROT13, Caesar, ROT47, or Atbash cipher to text.

69x

d:

/datauri

Data URI

from Encode & Decode

Turn a file or text into a data: URI, or decode one back. Stays in your browser.

31x

U+

/uni

Unicode Inspector

from Encode & Decode

Break text into code points — U+ value, decimal, HTML entity, UTF-8 bytes.

35x

xn--

/punycode

Punycode / IDN

from Encode & Decode

Convert internationalized domain names to punycode and back.

41x

0xF

/hexdump

Hex Viewer

from Encode & Decode

Inspect text or a file as a classic hex dump with offsets and ASCII.

73x

?→

/magic

Smart Decoder

from Encode & Decode

Paste an opaque blob; it guesses the encoding — Base64, hex, URL, JWT, gzip — and decodes it.

65x

é

/charset

Character Encoding

from Encode & Decode

Decode bytes with legacy charsets, encode text to UTF-8, UTF-16 or Latin-1, and repair mojibake.

78x

f?

/filetype

File Type Identifier

from Encode & Decode

Detect what a file really is from its magic bytes — pick a file or paste hex/base64, get the true type, MIME and an extension-mismatch check.

45x

{}

/json

JSON / YAML / TOML

from Data & Config

Validate and convert between JSON, JSON5, JSONC, YAML, and TOML in any direction — comments and trailing commas handled client-side.

40x

{+}

/jsontree

JSON Tree & Query

from Data & Config

Explore JSON as a collapsible tree — expand, collapse, search keys and values, click any node to copy its JSONPath, or run a JSONPath expression to list and highlight matches.

32x

</>

/xml

XML Studio

from Data & Config

Validate and format XML, run XPath 1.0 queries, apply XSLT 1.0 stylesheets, and convert between JSON and XML — all in your browser.

40x

,[]

/csv

CSV ↔ JSON

from Data & Config

Convert between CSV and JSON array. First row is headers.

76x

xls

/xlsx

Excel ↔ CSV / JSON

from Data & Config

Convert a spreadsheet (.xlsx, .xls, .ods, .csv) to CSV or JSON, or turn CSV/JSON into a downloadable .xlsx — in your browser.

65x

?=&

/qs

Query String

from Data & Config

Paste a URL or query string and see its parameters decoded into a table.

31x

$x=

/env

.env Parser

from Data & Config

Paste a .env file and inspect the parsed key-value pairs.

78x

SEL

/sqllab

SQL Lab

from Data & Config

Load a CSV, JSON, or .sqlite file and query it with real SQL — joins, aggregates, window functions. A full SQLite engine in your browser. Export CSV/JSON/Markdown.

33x

{T}

/types

JSON → Types

from Data & Config

Generate TypeScript, Zod, JSON Schema, Go, Rust, Pydantic, or Kotlin types from a JSON sample.

582x

{≠}

/jsondiff

JSON Diff

from Data & Config

Compare two JSON documents semantically — key order ignored.

33x

✓?

/valid

Validators

from Data & Config

Validate an IBAN, credit card, BIC/SWIFT, ISBN, or EU VAT number.

29x

▦

/jtable

JSON → Table

from Data & Config

Turn a JSON array into a sortable, filterable table. Export Markdown or CSV.

63x

▨

/chart

Chart Maker

from Data & Config

Paste CSV or JSON and turn it into a bar, line, pie or scatter chart, then export it as PNG or SVG. Rendered in your browser.

61x

dc

/compose

docker run → Compose

from Data & Config

Paste a docker run command and get an equivalent docker-compose.yml service.

74x

⇄:

/proxygen

Reverse Proxy Config

from Data & Config

Generate Nginx, Caddy, and Traefik reverse-proxy config from one form — HTTPS, WebSockets, HSTS, basic auth.

63x

☎

/phone

Phone Number Parser

from Data & Config

Parse a phone number to E.164 and detect its country and dialling code.

30x

◈

/geojson

GeoJSON Viewer

from Data & Config

Preview GeoJSON geometry, see a feature summary and bounding box. No map tiles, nothing uploaded.

85x

har

/har

HAR Viewer

from Data & Config

Inspect a browser-exported .har file — requests, status, size and timing. Nothing uploaded.

23x

cc:

/commitlint

Commit Linter

from Data & Config

Check a commit message against Conventional Commits — type, scope, breaking change, and the semver bump it implies.

26x

v1.2

/semver

Semver Calculator

from Data & Config

Compare semantic versions, test range satisfaction (^ ~ x-ranges hyphen ||) and compute the next bump.

61x

{api}

/openapi

OpenAPI Validator

from Data & Config

Validate an OpenAPI 3.x or Swagger 2.0 spec (JSON or YAML) — missing fields, operations without responses, duplicate operationIds.

29x

mk:

/makefile

Makefile Visualizer

from Data & Config

Paste a Makefile and explore its targets as a dependency tree, with the build order and cycle detection.

65x

DKR

/dockerfile

Dockerfile Linter

from Data & Config

Lint a Dockerfile against Hadolint-style best practices — image tags, apt cleanup, COPY vs ADD, JSON CMD, non-root user.

29x

CVE

/deps

Dependency Vulnerability Scanner

from Data & Config

Paste a lockfile and find known CVEs in your dependencies, checked against a daily local mirror of the OSV database. No third-party calls.

40x

{✓}

/jsonschema

JSON Schema Validator

from Data & Config

Validate a JSON document against a JSON Schema, live in your browser.

31x

[]:

/serialized

Serialized Data Inspector

from Data & Config

Decode and encode MessagePack, CBOR, Protobuf wire format and PHP serialize() — all in your browser.

62x

+-

/diff

Diff

from Text

Compare two text blocks line-by-line, or create and apply a unified-diff patch.

58x

.*

/regex

Regex Lab

from Text

Regex workbench — live highlight, capture-group table, find-and-replace preview, plain-English explainer, pattern library, cheat sheet, and generate-from-samples — all in your browser.

32x

aA_

/case

Case Converter

from Text

Convert identifiers between camelCase, snake_case, PascalCase, kebab-case, and more.

74x

str

/str

String Ops

from Text

Reverse, trim, pad, repeat, number lines, and remove blank/duplicate lines.

64x

A-Z

/sort

Sort / Filter

from Text

Sort lines alphabetically, numerically, or by length. Remove duplicates.

26x

Σ

/text

Text Stats

from Text

Word, character and line counts, reading time, and word frequency.

86x

**

/md

Markdown

from Text

Write Markdown, preview the rendered HTML output.

87x

𝐁𝑖

/post

Social Post Formatter

from Text

Write a post in a rich-text editor and copy Unicode-styled text that keeps its bold and italics on LinkedIn or X. With live post previews.

26x

a-b

/slug

Slugify

from Text

Turn any text into a clean, URL-safe slug. Accents stripped, spaces collapsed.

70x

¶✕

/plain

Plain Text & Invisible Characters

from Text

Reveal invisible characters (tabs, NBSP, zero-width chars, BOMs) in a highlighted preview, then strip them along with smart quotes, fancy dashes and rich-text junk.

44x

|-|

/mdtable

Markdown Table

from Text

Turn CSV or TSV data into an aligned Markdown table.

29x

</>

/beautify

Code Formatter

from Text

Beautify or minify JS, JSON, CSS, HTML; pretty-print SQL across dialects; format or minify GraphQL queries and SDL schemas.

71x

A∩B

/lists

List Comparer

from Text

Compare two lists — intersection, differences, union, and duplicates.

24x

<>↓

/htmlmd

HTML → Markdown

from Text

Convert HTML into clean Markdown, live in your browser.

24x

<>@

/emailhtml

Email HTML Builder

from Text

Turn Markdown or HTML into email-client-safe HTML — CSS inlined, Outlook-proofed with a table wrapper, live sandboxed preview, copy as rich text.

25x

<jsx

/jsx

HTML → JSX

from Text

Paste HTML, get JSX — className, style objects, camelCased attributes, self-closed tags.

60x

@↓

/emailnorm

Email Normalizer

from Text

Canonicalize emails — lowercase, strip Gmail dots and +tags — then dedupe a list.

65x

>js

/js

JS Console

from Run Code

Run JavaScript or TypeScript in a sandboxed console, right in your browser.

25x

>py

/py

Python Console

from Run Code

Run real Python in your browser — a full CPython interpreter (Pyodide) in a sandboxed worker. REPL or script, standard library included. Nothing uploaded.

45x

jav

/java

Java Sandbox

from Run Code

Run small Java programs with a built-in interpreter. Nothing leaves your browser.

27x

wsm

/wasm

WebAssembly Runner

from Run Code

Load, inspect, instantiate and call .wasm modules right in your browser.

59x

tok

/tokens

Token Counter & Visualizer

from AI & Prompts

Exact BPE tokenization with colored token spans and token IDs (o200k_base / cl100k_base), plus a heuristic token estimate and per-1M-token cost calculator.

28x

{{}}

/prompt

Prompt Template

from AI & Prompts

Write a prompt with {{variables}}, fill them in, and get the finished prompt.

31x

fn{}

/toolschema

Tool Schema Builder

from AI & Prompts

Visually build a function/tool-calling JSON schema for Claude or OpenAI.

70x

[..]

/chatjson

Chat Message Builder

from AI & Prompts

Build a conversation and export the JSON body for the Claude or OpenAI chat APIs.

58x

mcp

/mcpconfig

MCP Client Config Generator

from AI & Prompts

Describe one MCP server, get ready-to-paste config for Claude Code, Claude Desktop, VS Code and Cursor.

53x

llm

/llmstxt

llms.txt Generator & Validator

from AI & Prompts

Generate an llms.txt file for your site from a simple form, or paste one to validate it against the spec.

34x

md

/agentsmd

AGENTS.md / CLAUDE.md Builder

from AI & Prompts

Build an AGENTS.md or CLAUDE.md from a checklist of best-practice sections, and grade an existing one for completeness.

82x

!ai

/injscan

Prompt Injection Scanner

from AI & Prompts

Lint text or documents for prompt-injection risks — override phrases, invisible unicode smuggling and markdown-image exfiltration. A lint, not a guarantee.

40x

A|B

/abcompare

LLM Output Comparator

from AI & Prompts

Compare two LLM outputs side by side — word-level diff, similarity, length and a blind A/B taste-test tally.

45x

jsl

/jsonl

JSONL Dataset Viewer

from AI & Prompts

Open a large .jsonl dataset locally, page through records, and validate each line against OpenAI, Anthropic or ShareGPT fine-tune shapes.

71x

mcp?

/mcptest

MCP Server Tester

from AI & Prompts

Connect to a remote Streamable-HTTP MCP server, list its tools, and call one — proxied through the server with an SSRF guard.

79x

5?

/poker

Planning Poker

from Agile & Scrum

Estimate stories as a team in real time — share a room code, everyone votes, cards stay hidden until you reveal. Relayed live, nothing stored.

31x

v↗

/sprint

Sprint Capacity & Velocity

from Agile & Scrum

Work out team capacity, track velocity from past sprints, and forecast how many sprints the backlog needs.

65x

⟲?

/retro

Sprint Retro Formats

from Agile & Scrum

Browse sprint retrospective formats with steps, timeboxes and facilitation tips. Filter by team mood and time, get a ready-made agenda, or let it pick a format for you.

42x

#

/hash

Hash & Checksum

from Crypto & Passwords

Hash text or a file with MD5, SHA-1, SHA-256, SHA-384, SHA-512, SHA3, Keccak-256, BLAKE3 and CRC32 — all in your browser, nothing is uploaded.

28x

h()

/hmac

HMAC

from Crypto & Passwords

Generate an HMAC signature with SHA-256, SHA-384, SHA-512, or SHA-1 — entirely in your browser.

57x

***

/pass

Password

from Crypto & Passwords

Generate random passwords, EFF diceware passphrases, PINs and pronounceable passwords, and check password strength.

44x

id

/uuid

UUID / ULID

from Crypto & Passwords

Generate UUID v4, time-ordered v7, name-based v5 or ULID identifiers — and decode any UUID.

40x

2FA

/totp

TOTP / 2FA Code

from Crypto & Passwords

Generate the live time-based one-time code from a Base32 secret.

57x

12w

/bip39

BIP39 Seed Phrase

from Crypto & Passwords

Generate or validate a BIP39 mnemonic recovery phrase — 12 to 24 words with a real checksum, all in your browser.

26x

$2

/pwhash

Password Hash

from Crypto & Passwords

Hash a password with scrypt, bcrypt or Argon2id (OWASP defaults), or verify one against a stored hash.

72x

509

/cert

Certificate Decoder

from Crypto & Passwords

Decode X.509 certificates, CSRs, and SSH public keys in your browser.

27x

AES

/aes

AES Text Encryption

from Crypto & Passwords

Encrypt or decrypt text with a passphrase (AES-256-GCM). Stays in your browser.

30x

age

/age

age Encryption

from Crypto & Passwords

Encrypt or decrypt text and files with age — X25519 recipients or scrypt passphrases, interoperable with the age/rage CLIs. Fully in your browser.

44x

K/N

/shamir

Shamir's Secret Sharing

from Crypto & Passwords

Split a secret into N shares so any K reconstruct it — fewer reveal nothing. GF(256) math, entirely in your browser.

17x

pwn

/pwned

Password Breach Check

from Crypto & Passwords

Check if a password has appeared in a known data breach, using the Have I Been Pwned k-anonymity range API — only 5 characters of its hash ever leave your browser.

22x

k/p

/keypair

Key Pair Generator

from Crypto & Passwords

Generate RSA, ECDSA, or Ed25519 key pairs and export PEM/JWK.

21x

h:p

/htpasswd

Basic Auth / htpasswd

from Crypto & Passwords

Build an HTTP Authorization: Basic header and .htpasswd lines, in your browser.

18x

0x

/baseconv

Base Convert

from Numbers & Math

Convert integers between decimal, binary, hex, and octal.

47x

1,2k

/num

Number Format

from Numbers & Math

Format numbers with commas, words, hex, binary, and scientific notation.

64x

XIV

/roman

Roman Numerals

from Numbers & Math

Convert between integers and Roman numerals.

22x

km

/unit

Unit Converter

from Numbers & Math

Convert length, mass, temperature, data size, speed, area, and volume.

63x

%

/calc

Percentage Calc

from Numbers & Math

Percentages, change, tips, and VAT — the everyday math, in one place.

59x

17

/prime

Primes & Factors

from Numbers & Math

Primality check, prime factorization, and next/previous prime.

26x

x̄σ

/stats

Number Stats

from Numbers & Math

Mean, median, mode, standard deviation, and percentiles of a number list.

51x

∿

/plot

Function Plotter

from Numbers & Math

Plot mathematical functions of x. Pan, zoom, multiple curves.

44x

¾

/frac

Fractions

from Numbers & Math

Exact fraction arithmetic, simplify, and decimal ↔ fraction conversion.

32x

gcd

/gcd

GCD & LCM

from Numbers & Math

Greatest common divisor and least common multiple, with Euclid steps.

67x

nCr

/comb

Combinatorics

from Numbers & Math

Factorials, permutations, and combinations — exact big-integer results.

72x

x²

/solve

Equation Solver

from Numbers & Math

Solve linear, quadratic, and cubic equations — real and complex roots.

52x

[M]

/matrix

Matrix Calculator

from Numbers & Math

Multiply, add, and invert matrices — plus determinant, rank, and trace.

156x

%+

/finance

Finance Calculator

from Numbers & Math

Compound interest & savings growth, plus loan payments and a full amortization schedule.

64x

f(

/eval

Math Evaluator

from Numbers & Math

Type a math expression and get the result — functions, constants, factorial.

57x

&|^

/bit

Bitwise Calculator

from Numbers & Math

AND, OR, XOR, NOT and shifts across decimal, hex, octal and binary.

59x

fl

/float

Float Inspector

from Numbers & Math

See how a number is stored as an IEEE-754 float — sign, exponent, mantissa.

64x

△

/triangle

Triangle Solver

from Numbers & Math

Solve any triangle from three known sides or angles — SSS, SAS, ASA, AAS, or SSA — with a to-scale drawing.

52x

ΩVI

/ohm

Ohm's Law

from Electronics

Enter any two of voltage, current, resistance, or power — get the other two, with the formula used.

51x

▮▮▮

/rescolor

Resistor Color Code

from Electronics

Decode resistor color bands to a value, or find the bands for a value. 4, 5, and 6-band.

56x

◇R

/ledres

LED Resistor

from Electronics

Size the series resistor for an LED or string — supply voltage, forward voltage, current. Nearest E12 + power.

25x

V÷

/vdiv

Voltage Divider

from Electronics

Compute the output of a two-resistor divider, the current and power, or pick resistors for a target output.

62x

ƒc

/filter

Filter Calculator

from Electronics

Cutoff frequency of an RC or RL filter, and the resonant frequency of an LC tank — solve any unknown.

23x

104

/capcode

Capacitor Code

from Electronics

Decode a 3-digit capacitor code (e.g. 104) to capacitance, with tolerance letter, or convert pF / nF / µF.

25x

555

/ne555

555 Timer

from Electronics

Astable frequency, duty cycle and period, or monostable pulse width — from the resistors and capacitor.

20x

R∥R

/rcomb

Series / Parallel

from Electronics

Combine resistors or capacitors in series and parallel — enter a list of values, get the total.

61x

Xc

/react

Reactance & Resonance

from Electronics

Capacitive and inductive reactance at a frequency, and the resonant frequency of an LC circuit.

21x

mm²

/awg

Wire Gauge (AWG)

from Electronics

Convert AWG to diameter and area, with copper resistance per metre and a rough ampacity guide.

20x

dB

/db

Decibel Calculator

from Electronics

Convert power or voltage ratios to decibels and back, and dBm to watts.

24x

▷∞

/opamp

Op-Amp Gain

from Electronics

Gain and output of an inverting or non-inverting op-amp from its two resistors.

443x

317

/lm317

LM317 Regulator

from Electronics

Set the output voltage of an LM317 regulator — compute Vout from R1/R2, or solve R2 for a target.

20x

+−

/battery

Battery Life

from Electronics

Estimate run time from battery capacity and load current, with a derating factor.

48x

V↓

/vdrop

Voltage Drop

from Electronics

Voltage lost down a cable run from its length, current and cross-section. Shows % drop, load voltage and power wasted.

54x

PCB

/pcb

PCB Trace Width

from Electronics

Minimum copper trace width for a current using IPC-2221 — plus resistance and voltage drop for a given length.

58x

S·P

/battpack

Battery Pack Config

from Electronics

Combine cells in series and parallel — pack voltage, capacity, energy and total cell count, with a chemistry picker.

35x

Vz

/zener

Zener Diode

from Electronics

Size the series resistor for a zener shunt regulator — resistor value, power rating and worst-case zener dissipation.

39x

Q

/bjt

Transistor Biasing

from Electronics

DC operating point of a voltage-divider biased BJT — base/collector/emitter currents and voltages, Vce and the region.

63x

∿V

/ripple

PSU Ripple

from Electronics

Size the smoothing capacitor after a rectifier from load current and target ripple — nearest standard value and actual ripple.

24x

⏛

/fuse

Fuse Selector

from Electronics

Pick a fuse rating from the load current and inrush — 125% headroom, ambient derating, fast vs slow-blow.

51x

⊓⊔

/pwm

PWM Duty Cycle

from Electronics

Convert PWM duty cycle to average voltage and back, with on-time, off-time, period and RMS.

58x

R°

/ntc

Thermistor NTC

from Electronics

Convert NTC thermistor resistance ↔ temperature with the Beta model or Steinhart-Hart, and see the R-T curve.

18x New

{⚡}

/circuit

Circuit Builder

from Electronics

Describe a circuit in a few lines of code and get a schematic, a PCB layout and Circuit JSON back. Runs in your browser.

12x New

⌁▤

/kicad

KiCad Viewer

from Electronics

Open a KiCad schematic or PCB in the browser — pan, zoom, toggle layers and click a part to read its properties. No KiCad install, nothing uploaded.

30x

⇆

/serial

Serial Monitor & Flasher

from Electronics

A browser serial terminal and ESP firmware flasher — talk to any Arduino or USB-serial board, and flash ESP32/ESP8266 chips. Nothing installed.

64x

λf

/wavelength

Frequency ↔ Wavelength

from Radio & RF

Convert between frequency and wavelength either way, with a velocity factor and the radio band shown on the spectrum.

23x

λ/4

/antenna

Antenna Length

from Radio & RF

Physical full/half/quarter/⅝-wave antenna lengths from a frequency, with a velocity factor for real wire.

72x

dB↓

/fspl

Free-Space Path Loss

from Radio & RF

Ideal line-of-sight signal loss from frequency and distance, with a loss-versus-distance curve.

18x

ΣdB

/linkbudget

Link Budget

from Radio & RF

Add up transmit power, antenna gains and losses to get received power and link margin versus receiver sensitivity.

62x

12#

/dtmf

DTMF Tones

from Radio & RF

Play and decode telephone touch-tones — tap a key or play a sequence, and see the two-frequency tone pairs.

42x

MHz

/bandplan

Ham Band Plan

from Radio & RF

Amateur radio band reference — wavelength, frequency range and typical use across the three IARU regions. Filter and sort.

17x

ToA

/lorawan

LoRaWAN Airtime

from IoT & Protocols

Exact LoRa time-on-air from SF/BW/CR with the Semtech formula, plus duty-cycle and TTN fair-use limits and an SF7-12 comparison.

49x

◧

/payload

Protocol Payload Size

from IoT & Protocols

Break a transmission into header + payload + footer for MQTT, Modbus, CoAP, BLE, CAN, TCP/UDP and more — with efficiency and airtime.

54x

⌹

/mqtt

MQTT Topic Tree

from IoT & Protocols

Paste MQTT topics and see them as a collapsible tree — shared branches, depth and wildcards at a glance.

43x

4xx

/modbus

Modbus Register

from IoT & Protocols

Decode a Modbus address to its table, function code and PDU offset, and convert registers to/from int and float across byte orders.

63x

(m)

/mesh

Meshtastic Toolkit

from IoT & Protocols

Six Meshtastic calculators in one page: airtime, node range, hop coverage, channel builder, packet size and region reference.

38x

PV

/solar

Solar Panel Yield

from Energy

Estimate a rooftop solar array's yearly output from size, region, orientation and tilt, with a monthly breakdown.

46x

ROI

/batteryroi

Home Battery ROI

from Energy

Will a home battery pay for itself? Annual saving, payback time and lifetime profit from buy vs feed-in prices.

23x

A|B

/tariff

Tariff Comparator

from Energy

Compare a flat single-rate electricity tariff against a day/night plan for your usage and night-time share.

22x

CO₂

/co2

Device CO₂

from Energy

Yearly energy and CO₂ footprint of your devices from wattage, run-time and your grid's carbon intensity.

47x

EV

/evcharge

EV Charging Time

from Energy

How long to charge an EV between two states of charge, with DC rapid-charge taper above 80% and range added.

26x

ΣA

/peakload

Peak Load

from Energy

Add up appliances running at once and check the total current against your main fuse or breaker.

127x

η

/scop

Heat Pump SCOP

from Energy

Seasonal COP of a heat pump — from EN 14825 part-load test points or heat-out ÷ electricity-in, with ErP energy-label class and running cost.

36x

⊚

/filament

Filament Calculator

from Fabrication

Convert 3D-printing filament between length and weight by material and diameter, and get the spool cost.

46x

rpm

/feeds

CNC Feeds & Speeds

from Fabrication

Spindle RPM and feed rate from cutting speed, tool diameter, flute count and chip load — with material presets.

18x

cut

/lasercut

Laser Cut Time & Kerf

from Fabrication

Estimate a laser job's run time from path length and speed, and compute kerf compensation for accurate parts.

51x

stp

/steps

Steps per mm

from Fabrication

Steps-per-mm for a belt or leadscrew axis, plus the Klipper rotation_distance. For 3D printers and CNC.

22x

◳

/stl

3D Model Viewer

from Fabrication

View an STL, OBJ, 3MF, PLY or GLB/glTF model in your browser — spin it, read mesh stats, snapshot a PNG, or export an offline viewer. Nothing uploaded.

55x New

⬡

/scad

SCAD Modeller

from Fabrication

Write OpenSCAD code and render real 3D geometry in your browser — live preview, customizer sliders, STL export. Nothing uploaded.

78x

▱

/outline

Photo to STL

from Fabrication

Turn a photo into a 3D print in your browser: trace a cutting silhouette (SVG / DXF / extruded STL), emboss a relief plaque, generate a backlit lithophane, or let an on-device AI depth model pop the scene into 3D — with a live 3D preview. Nothing uploaded.

70x

GH

/goldenhour

Golden Hour

from Outdoors & Sky

Blue hour, golden hours and twilight for any place and date — the light photographers plan around.

81x

az°

/sunpos

Sun Position

from Outdoors & Sky

The sun's azimuth and altitude for a place and moment, drawn on a sky chart — for shadows, solar and photography.

26x

↑↓

/sunrise

Sunrise & Sunset

from Outdoors & Sky

Sunrise, sunset and day length for any location and date, with civil twilight and solar noon.

23x

☾

/moon

Moon Phase

from Outdoors & Sky

The moon phase for any date — name, illumination and age, with the lit disc drawn.

24x

Td

/dewpoint

Dew Point

from Outdoors & Sky

Dew point from temperature and humidity (Magnus formula), with a mugginess comfort scale.

57x

~°

/windchill

Wind Chill / Heat Index

from Outdoors & Sky

The "feels-like" temperature — wind chill in the cold, heat index in the heat — from temp, wind and humidity.

59x

XY°

/coords

Coordinates Converter

from Outdoors & Sky

Convert a location between decimal degrees, degrees-minutes-seconds and MGRS, plotted on a world grid.

41x

A↔B

/gpsdist

GPS Distance

from Outdoors & Sky

Great-circle distance and bearing between two latitude/longitude points (Haversine).

41x

kcal

/calories

Calorie Burn

from Outdoors & Sky

Calories burned by an activity from its MET value, your weight and the time spent.

47x

h↑

/hiking

Hiking Time

from Outdoors & Sky

Estimate walk time with Naismith's rule from distance and ascent, with a Langmuir descent correction.

28x

⚖

/packing

Packing List

from Outdoors & Sky

Build a kit list with weights — total, base weight versus consumables, and a target check.

24x

✷

/stars

Star & Planet Finder

from Outdoors & Sky

Point your phone at the sky to identify stars, planets, the Sun and Moon, with an optional camera overlay and constellation lines.

85x

NPF

/astroplan

Astrophoto Planner

from Outdoors & Sky

Plan a night of astrophotography: max exposure before star trails (500 rule and NPF rule), the astronomical darkness window, and moon interference for the night.

34x

N↑

/scope

Telescope Setup

from Outdoors & Sky

Set up a GoTo mount in the field — bubble level, true-north compass with magnetic declination, your site data in SynScan handset format, and the Polaris clock position for polar alignment.

22x

⚑

/hunt

Scavenger Hunt

from Outdoors & Sky

Build a city scavenger hunt on a map — waypoints, photos, hints and photo tasks — then follow every team live. Dutch and English.

43x

>>

/epoch

Timestamp

from Date & Time

Convert between Unix timestamps and human-readable dates.

82x

TZ

/tz

Timezone Converter

from Date & Time

Convert a datetime between any two IANA timezones.

46x

◷

/time

Current Time

from Date & Time

Live local and UTC clock with ISO 8601, Unix epoch, ISO week and day of year. Also served at /utc with UTC first.

34x

cal

/dt

Date & Duration Calculator

from Date & Time

Difference between two dates, add/subtract a duration, see how long ago a date was, and convert seconds to a human duration string.

59x

(@)

/cron

Cron

from Date & Time

Parse a cron expression. Get a plain-English description and next 5 run times.

57x

0:00

/timer

Timer / Stopwatch

from Date & Time

Stopwatch with laps, countdown with alarm, and a fully customizable Pomodoro timer whose settings live in the URL.

22x

*id

/snowflake

ID Timestamp Decoder

from Date & Time

Extract the date from Discord/Twitter snowflakes, ULIDs, UUIDs, ObjectIds, unix stamps.

18x

[#]

/datepoll

Group Date Picker

from Date & Time

Propose dates, share a link, and let the group mark when they can make it. Anonymous, no accounts.

36x

M-F

/workdays

Business Days Calculator

from Date & Time

Count business days between two dates, or add working days to a date, with custom weekends and holidays.

45x

ETA

/eta

ETA Calculator

from Date & Time

I have done X of Y in this much time — see the rate, time remaining and the finish time, live.

20x

●

/color

Color

from Web & Design

Convert between HEX, RGB, HSL, HSV, OKLCH, OKLab, CIE Lab, and CMYK. Live preview swatch.

51x

◐

/palette

Palette / Contrast

from Web & Design

Build a palette from a base color or an image, and check WCAG contrast ratios.

54x

▤

/gradient

CSS Gradient

from Web & Design

Build linear, radial, and conic gradients. Copy the CSS.

38x

▣

/shadow

Box Shadow

from Web & Design

Layered CSS box-shadow builder with live preview.

62x

rem

/px

px ↔ rem

from Web & Design

Convert px, rem, em, pt, and % with a configurable base size.

67x

16:9

/ratio

Aspect Ratio

from Web & Design

Simplify W×H to a ratio, or solve a missing dimension.

22x

og:

/meta

Meta Tags

from Web & Design

Generate title, Open Graph, and Twitter card tags for a page.

59x

⬡

/svg

SVG Tools

from Web & Design

Preview, minify, CSS-encode, and rasterize SVG markup to PNG.

63x

[:]

/favicon

Favicon Maker

from Web & Design

Turn an emoji, letters or your own image into a full favicon set — PNGs plus favicon.ico.

24x

W×H

/placeholder

Placeholder Image

from Web & Design

Generate placeholder images at any size, in your browser.

55x

</>

/codeshot

Code Image

from Web & Design

Turn a code snippet into a styled image with a window frame and syntax highlighting. Export as PNG.

47x

◑

/cvd

Color-Blindness Simulator

from Web & Design

See how an image or palette looks with protan, deutan, or tritan color vision.

65x

⤳

/mermaid

Mermaid Diagram

from Web & Design

Render Mermaid diagrams — flowcharts, sequence, class, gantt — and download the SVG.

45x

⋈

/dot

Graphviz DOT Renderer

from Web & Design

Render Graphviz DOT diagrams — dot, neato, fdp, circo, twopi layouts — and download SVG or PNG.

32x

Aa

/font

Font Inspector

from Web & Design

Inspect a TTF/OTF/WOFF/WOFF2 font: name table, weight/width/slant, glyph count, Unicode ranges, OpenType features, and a live specimen preview.

49x

∫

/bezier

cubic-bezier Editor

from Web & Design

Drag handles to shape a CSS easing curve, then copy the cubic-bezier().

49x

⊳⊲

/clamp

CSS clamp()

from Web & Design

Build a responsive clamp() that scales fluidly between two viewport widths.

64x

{;}

/cssjs

CSS ↔ JS Object

from Web & Design

Convert CSS declarations to a React/JS inline-style object and back.

45x

"

/quoteimg

Quote → Image

from Web & Design

Turn a quote into a shareable image — pick colors and size, download a PNG.

24x

▦

/paint

Pixel Paint

from Web & Design

Draw pixel art on a grid — pencil, fill, eyedropper, undo — then export a PNG. Stays in your browser.

22x

LOL

/meme

Meme Generator

from Web & Design

Drop an image, add captions, images and emojis, then download or share the meme. All client-side.

52x

◳

/avatar

Avatar Generator

from Web & Design

Turn any name or string into a unique, deterministic identicon. Download a PNG.

41x

▨

/pattern

Pattern Generator

from Web & Design

Build a seamless tileable background pattern. Copy the SVG or CSS, or download it.

66x

▦

/grid

CSS Grid Generator

from Web & Design

Design a CSS grid with a live preview — columns, rows, gaps — and copy the code.

25x

▢

/glass

Glassmorphism

from Web & Design

Build a frosted-glass card with backdrop-filter and copy the CSS.

51x

Hw

/handwrite

Handwriting Simulator

from Web & Design

Turn typed text into a hand-drawn look — jittered, tilted letters — and export it as SVG or PNG.

16x

◎

/illusion

Optical Illusion

from Web & Design

Generate static optical illusions that seem to shimmer or bend — scintillating grid, Hermann grid, café wall. Export PNG.

63x

#A

/img2ascii

Image to ASCII Art

from Web & Design

Turn an image into text-based ASCII art. Adjust width and character set, then copy or download. In your browser.

58x

░

/blurhash

BlurHash Generator

from Web & Design

Turn an image into a short BlurHash placeholder string, with a live decoded preview. Encoded in your browser.

62x

◌

/loader

CSS Loader Generator

from Web & Design

Pick a pure-CSS loading spinner, tune color, size and speed, and copy a self-contained snippet.

19x

⬭

/blob

Blob & Border-Radius

from Web & Design

Sculpt organic shapes — fancy 8-value border-radius CSS or a smooth random SVG blob to download.

21x

bot

/robots

Robots.txt Tester

from Web & Design

Paste a robots.txt and test URL paths for any crawler — RFC 9309 rules, entirely in your browser.

57x

~~~

/x/ping

Ping

from Network

ICMP ping a hostname or IP. See round-trip times.

46x

NS:

/x/dns

DNS

from Network

Resolve A, AAAA, MX, TXT, CNAME and reverse (PTR) records.

24x

who

/x/whois

WHOIS

from Network

Look up registration info for a domain or IP.

48x

...

/x/trace

Traceroute

from Network

Trace the network path to a host, hop by hop.

25x

HDR

/x/headers

HTTP Headers

from Network

Fetch and inspect HTTP response headers for any URL.

44x

:80

/x/port

Port Check

from Network

Check if a TCP port is open on a remote host.

45x

MX:

/x/email

Email DNS Check

from Network

Check a domain’s MX, SPF, DMARC and DKIM records.

71x

TLS

/x/ssl

TLS / SSL Check

from Network

Inspect the live TLS certificate on a host — chain, expiry, SANs, protocol.

77x

IP/

/cidr

IP & Subnet Toolkit

from Network

IPv4 subnet calculator, VLSM planner, and range ↔ CIDR converter — all in your browser.

53x

[ip]

/ip

My IP

from Network

See your public IP address, user-agent, and Accept-Language header.

22x

UA

/ua

User-Agent Parser

from Network

Break a User-Agent string into browser, engine, OS and device.

16x

↯

/req

HTTP Request Runner

from Network

Send an HTTP request through the server (no CORS), import a curl command into the builder, inspect the response, and export as curl, fetch, Python, Go, PHP, Ruby or HTTPie. Public hosts only.

25x

MAC

/mac

MAC Address Tools

from Network

Generate random MAC addresses or look up the vendor (OUI) behind one.

53x

A+

/secheaders

Header Security Check

from Network

Paste HTTP response headers and get a security grade — HSTS, CSP, frame and sniffing protection, with fixes.

25x

CSP

/csphash

CSP Hash Generator

from Network

Turn an inline script or style snippet into the sha256/384/512 CSP source token a browser will accept instead of 'unsafe-inline'.

35x

⇄

/socket

WebSocket Tester

from Network

Connect to any ws:// or wss:// endpoint straight from your browser, send frames and inspect what comes back.

65x

?×

/clean

URL Cleaner

from Network

Unwrap redirect-wrapped links (SafeLinks, Google, Proofpoint) and strip tracking parameters.

23x

::

/qr

QR Code

from Generate

Generate a QR code from a URL, plain text, or WiFi network credentials. Download as SVG.

61x

¶

/lorem

Lorem Ipsum

from Generate

Generate placeholder text by word, sentence, or paragraph count.

44x

f@k

/fake

Fake Data

from Generate

Generate test data — names, personas, companies, KVK/BSN/IBAN; export JSON, SQL or Postgres COPY.

54x

?utm

/utm

UTM Builder

from Generate

Build campaign URLs with utm_source, medium, and campaign parameters.

22x

▶ⓘ

/ythumb

YouTube Thumbnail Grabber

from Generate

Get every YouTube video thumbnail URL — default, medium, high, standard and max-res, plus the 3 frame thumbnails. Built from the URL in your browser.

51x

.ig

/gitignore

.gitignore

from Generate

Compose a .gitignore from per-stack templates.

19x

(c)

/license

License Text

from Generate

Generate MIT, Apache-2.0, BSD, ISC, MPL, or Unlicense text, filled in.

51x

[31]

/ics

Calendar Event

from Generate

Create a calendar event and download it as an .ics file.

17x

VCF

/vcard

vCard Generator

from Generate

Build a contact card, download the .vcf, or share it as a QR code.

50x

|||l

/barcode

Barcode Generator

from Generate

Generate a Code 128 barcode from text or numbers. Download SVG or PNG.

52x

LLM

/learn/llm

How an LLM Works

from Learn

An interactive visual explainer — tokens, embeddings, attention, the transformer stack, and how the next token is sampled.

45x

JVM

/learn/jvm

How the JVM Works

from Learn

An interactive visual explainer — class loading, bytecode, the JIT, the heap and garbage collection, and the runtime stack.

22x

TS

/learn/ts

How TypeScript Works

from Learn

An interactive visual explainer — type checking, structural typing, inference, generics, and erasure to plain JavaScript.

58x

TLS

/learn/https

How HTTPS & TLS Work

from Learn

An interactive visual explainer — the TLS handshake, public vs symmetric keys, certificates, and the chain of trust behind the padlock.

22x

GIT

/learn/git

How Git Works

from Learn

An interactive visual explainer — snapshots vs diffs, the staging area, the blob/tree/commit object model, the commit graph, and what a branch really is.

19x

DNS

/learn/dns

How DNS Works

from Learn

An interactive visual explainer — the lookup walk from root to TLD to authoritative, record types, and how TTL caching keeps it fast.

21x

RTC

/learn/webrtc

How WebRTC Works

from Learn

An interactive visual explainer — peer-to-peer connections, signaling, ICE/STUN/TURN NAT traversal, and data channels (how /drop works).

24x

A65

/ascii

ASCII Table

from Reference

All 128 ASCII codes with decimal, hex, octal, binary, and names.

85x

4xx

/http

HTTP Codes

from Reference

HTTP status code reference — 1xx through 5xx.

30x

typ

/mime

MIME Types

from Reference

Look up MIME types by file extension or content-type string.

55x

:443

/ports

Port Numbers

from Reference

Reference of well-known TCP and UDP ports, with live filter.

21x

§¶

/symbols

Symbol Picker

from Reference

Click-to-copy arrows, dashes, math signs, currency, and more.

19x

[⌨]

/keycode

Key Event Inspector

from Reference

Press any key to see its JavaScript key, code, and keyCode.

52x

rwx

/chmod

Chmod

from Reference

Toggle Unix permission bits and get the numeric octal value instantly.

76x

:)

/emoji

Emoji Picker

from Reference

Search emoji by name and click to copy. Skin-tone variants included.

53x

git

/gitref

Git Cheatsheet

from Reference

The git commands you reach for — and the rescue ones you forget.

18x

[o]

/cam

Webcam Test

from Device Tests

Check your camera — live preview, resolution, frame rate, switch devices, snapshot. Nothing is uploaded.

23x

))

/mic

Microphone Test

from Device Tests

Test your mic — live input level, waveform, peak meter and device picker. Nothing is recorded.

24x

⌨

/keytest

Keyboard Test

from Device Tests

Press every key to check it registers. Keys light up and stay marked, so you can spot a dead or stuck key.

58x

[¦]

/mousetest

Mouse Test

from Device Tests

Test mouse buttons, scroll wheel, double-click and movement coordinates. Spot a failing button or jittery scroll.

54x

◢◣

/speaker

Speaker Test

from Device Tests

Test speakers and headphones — left/right channel tones, frequency sweep, and balance. Synthesized live.

20x

▦

/screentest

Dead Pixel Test

from Device Tests

Fill the screen with solid colors and patterns to find dead or stuck pixels and backlight bleed. Fullscreen.

47x

✛

/touchtest

Touchscreen Test

from Device Tests

Test a touchscreen or trackpad — multi-touch points, drag trails, and pressure. Multi-finger support.

18x

[+:]

/gamepad

Gamepad Test

from Device Tests

Test a game controller — buttons, triggers, analog sticks, and vibration. Xbox, PlayStation, generic.

26x

⟳

/sensors

Motion Sensors

from Device Tests

Read device motion sensors — orientation, accelerometer, and gyroscope. Best on a phone or tablet.

149x

ⓘ

/deviceinfo

Device Info

from Device Tests

Everything your browser reveals — screen, GPU, CPU, memory, network, battery, and supported features.

45x

FP

/fingerprint

Browser Fingerprint Self-Test

from Device Tests

See what a tracker could learn about you without cookies — canvas, WebGL, audio, fonts, hardware and a WebRTC local-IP check — with a plain-language entropy estimate. Nothing ever leaves your browser.

21x

CPU

/benchmark

Device Benchmark

from Device Tests

Benchmark your CPU, GPU and memory in the browser — single/multi-core throughput, WebGL render score with live FPS, and memory bandwidth. Tabs, deep-linkable. Nothing uploaded.

59x

GPS

/gps

GPS Dashboard

from Device Tests

Live speed and altitude from your device GPS — top speed, average, distance, elevation high/low, relative change and total climb.

31x

lux

/lightmeter

Light Meter

from Device Tests

Ambient light level in lux from the device sensor (where supported), with a reference scale.

67x

NFC

/nfc

NFC Scanner & Writer

from Device Tests

Read NFC tags and write text or a URL to them with the Web NFC API. Chrome for Android only. Waveshare e-paper writing works only in the 1234.nu Android app. Nothing uploaded.

84x

Hz~

/signal

Signal Generator

from Sensors & Signals

Generate pure tones, noise, and a frequency sweep with Web Audio — plus a step-by-step hearing test. Per-channel L/R.

27x

⌁

/lightning

Lightning Distance

from Sensors & Signals

Time the gap between a lightning flash and the thunder to find how far the storm is. Tap, or auto-detect with camera + mic.

56x

⌖

/trigstop

Trigger Stopwatch

from Sensors & Signals

A stopwatch you start and stop with a key, a loud sound, or motion in the camera. Time sprints, reactions, anything.

43x

◉))

/monitor

Remote Monitor

from Sensors & Signals

Two devices, one room code: one watches with its camera or listens on its mic, the other gets the live feed and sounds the alarm. Peer-to-peer, nothing recorded.

64x

SPL

/soundmeter

Sound Level Meter

from Sensors & Signals

A live loudness meter from your microphone — level, peak hold and a scrolling graph (relative, uncalibrated).

62x

((•))

/echoloc

Sound Triangulation

from Sensors & Signals

Turn several phones into a microphone network — mark each phone on a floorplan, calibrate with beeps, then locate claps and knocks together. Experimental.

46x

A4

/tuner

Instrument Tuner

from Music & Audio

Tune any instrument by ear with your microphone — live pitch, the nearest note and a cents needle. Adjustable A4. Nothing is recorded.

17x

MM

/metronome

Metronome

from Music & Audio

A drift-free metronome with time signature and subdivisions, plus a full tap-tempo pad — tap via mouse, touch or any key to get the BPM and beat interval in milliseconds.

28x

♪f

/notefreq

Note & Frequency

from Music & Audio

Convert between a note name, its MIDI number and its frequency in hertz — either way — with cents off the nearest note and an adjustable A4. Click to hear it.

19x

ms

/delay

Delay & Reverb Time

from Music & Audio

Turn a BPM into delay and reverb times in milliseconds for every note division — straight, dotted and triplet — plus the matching LFO frequency in hertz.

23x

♯♭

/capo

Transpose & Capo

from Music & Audio

Transpose a chord progression up or down any number of semitones, or find the capo fret that lets you play a song with easier open-chord shapes.

17x

scl

/scales

Scales & Chords

from Music & Audio

Look up the notes, intervals and degrees of any scale or chord from a root — major, minor, modes, pentatonic, blues, sevenths and more — shown on a keyboard and played back.

19x

MID

/midi

MIDI File Inspector

from Music & Audio

Drop a .mid file and inspect it — format, tracks, tempo and BPM, time and key signatures, instruments and note counts. Nothing is uploaded.

39x

[>]

/img/convert

Image Convert

from Media

Convert images between JPEG, PNG, WebP, AVIF, GIF, and TIFF. In your browser.

25x

[ ]

/img/resize

Image Resize

from Media

Resize or crop an image. Preserve ratio, cover, contain, or fill. In your browser.

23x

[v]

/img/compress

Image Compress

from Media

Shrink an image by re-encoding at a target quality. See the size saved. In your browser.

72x

H→

/heic

HEIC / HEIF Converter

from Media

Convert iPhone/Android .heic and .heif photos to JPEG or PNG, right in your browser. Nothing is uploaded.

84x

~^~

/aud/waveform

Audio Waveform

from Media

Visualize the waveform of an audio file. Runs entirely in the browser.

82x

>])

/aud/convert

Audio Convert

from Media

Convert audio between MP3, WAV, OGG, FLAC, AAC, and M4A. In your browser by default — nothing uploaded.

25x

|--|

/aud/split

Audio Trim

from Media

Extract a segment from an audio file by start and end time. In your browser by default — nothing uploaded.

24x

[>]

/vid/convert

Video Convert

from Media

Convert video to another format, extract audio, or make an animated GIF/WebP. Converts in your browser by default — nothing uploaded — with an optional server mode.

52x

[v]

/vid/compress

Video Compress

from Media

Shrink a video by re-encoding at a chosen quality. In your browser by default — nothing uploaded. See the size saved.

61x

|--|

/vid/trim

Video Trim

from Media

Cut a segment from a video by start and end time. No re-encoding, in your browser by default — instant and private.

27x

▣t

/vid/frames

Extract Frame

from Media

Grab a still frame from a video at any timestamp as a PNG. In your browser by default — nothing uploaded.

25x

♪✕

/vid/mute

Remove Audio

from Media

Strip the audio from a video, keeping the picture untouched. In your browser by default — instant and private.

25x

»

/vid/speed

Change Speed

from Media

Speed a video up or slow it down from 0.5× to 4×, audio kept in sync. In your browser by default — nothing uploaded.

24x

►))

/say

Text to Speech

from Media

Read text aloud with your browser voices. Nothing is uploaded.

47x

f/2

/exif

EXIF Viewer & Stripper

from Media

See a photo’s metadata (camera, GPS) and download a clean copy. Stays in your browser.

26x

PDF

/pdf

PDF Tools

from Media

View, merge, split, rotate, reorder/delete pages, images-to-PDF, PDF-to-images, extract text and stamp page numbers or a watermark — all in your browser. Files never leave your device.

30x

meta

/docmeta

Document Metadata Inspector & Stripper

from Media

See the hidden author names, file paths, template names and edit history baked into a PDF or Office file, then download a cleaned copy. Runs in your browser.

43x

Δ

/imgdiff

Image Diff

from Media

Compare two images pixel by pixel — side by side, an onion-skin blend, or a computed diff heatmap with a changed-pixel count. Runs entirely in your browser.

29x

(●)

/rec

Screen, Webcam & Audio Recorder

from Media

Record your screen, webcam, or microphone-only to a file, right in your browser. Nothing is uploaded.

44x

A→

/ocr

Image OCR

from Media

Extract text from an image, screenshot, scan or photo — locally in your browser with Tesseract. Nothing is uploaded.

35x

◎?

/imglabel

Image Labeling

from Media

Drop or pick a photo and get ranked content labels with confidence bars — classified on-device. Nothing is uploaded.

30x

))A

/stt

Speech to Text

from Media

Dictate with your microphone and get live text using your browser's speech recognition. Chrome and Edge.

62x

srt

/subs

Subtitle Converter

from Media

Convert subtitles between SRT and WebVTT and shift all timings. Everything happens in your browser.

22x

[fx]

/imgedit

Image Editor

from Media

Crop, rotate, flip, adjust colours, add a text watermark, and pixelate or redact regions — all on one canvas in your browser.

27x

▦

/scan

QR & Barcode Scanner

from Media

Decode QR codes and barcodes with your camera or from an image — nothing is uploaded.

41x

A⇄

/translate

Translate

from Media

Translate text between languages entirely on-device — your browser’s built-in translation, or the app’s offline ML Kit models. Nothing is uploaded.

62x

[✷]

/astrostack

Astro Image Stacker

from Media

Align and stack a burst of night-sky photos to cut noise, right in your browser — nothing is uploaded.

12x New

⊙⊙

/scan3d

3D Scan Capture

from Media

Point several phones at one scene and pool their photos on your PC for photogrammetry.

20x New

[✳]

/splat

Splat Viewer

from Media

View a Gaussian Splatting .splat or .ply scene in WebGL2 — orbit, pan, zoom, and record a flythrough video. Nothing is uploaded.

10x

Alfa

/nato

Spelling Alphabet

from Fun

Spell out text with the NATO phonetic alphabet (Alfa, Bravo…) or the Dutch spelling alphabet (Anna, Bernard…).

405x

·-·

/morse

Morse Code

from Fun

Encode or decode Morse code. Play back as audio.

27x

𝓐a

/fancy

Text Styler

from Fun

One input, every style — Unicode fonts, flip/mirror, mocking caps, leet, zalgo, noisy, typoglycemia, numeronym. All client-side.

73x

2d6

/dice

Dice Roller

from Fun

Roll dice with NdM+K notation and see the exact odds of every outcome. Cryptographically random.

28x

#A#

/banner

ASCII Banner

from Fun

Turn short text into a big ASCII-art banner.

21x

?!

/fact

Random Facts

from Fun

A random true fact from ten categories — science, space, history, and more.

25x

(o)

/coin

Coin Flip

from Fun

Flip a coin, get a yes/no, or ask the magic 8-ball — using the crypto RNG.

50x New

Y/N

/yesno

Yes or No

from Fun

Make a single-serving page that answers one question with a giant YES or NO, then share the link.

15x

#/

/asciidraw

ASCII Draw

from Fun

Draw with characters on a monospace grid, then copy or download the text art.

17x

◔

/wheel

Spin the Wheel

from Fun

Enter options and spin for a random winner, or just pick/shuffle a list. Crypto RNG.

26x

♪♫

/piano

Piano

from Fun

Play notes with your mouse, touch, or keyboard — synthesized live with Web Audio.

63x

ms

/reaction

Reaction Time

from Fun

Click when the screen turns green and measure your reaction time, with best and average over attempts.

57x

#7

/nummem

Number Memory

from Fun

Memorise a number that flashes up, then type it back — it grows by a digit each round.

62x

✺

/fan

Spinning Fan

from Fun

A calm desk fan that spins, wobbles, comes loose — and then sends your whole browser window spinning. A silly prank toy.

28x

z²

/fractal

Fractal Explorer

from Fun

Deep-zoom into the Mandelbrot and Julia sets — progressive rendering on all your CPU cores, smooth coloring, shareable views, PNG export.

24x

2k

/play/2048

2048

from Games

Slide and merge numbered tiles to reach 2048. Arrow keys or swipe.

33x

⚑

/play/mines

Minesweeper

from Games

Clear the field without detonating a mine. Three difficulty presets.

72x

W

/play/word

Word Guess

from Games

Six tries to guess the hidden five-letter word. Fully offline.

25x

4x4

/play/groups

Groups

from Games

Find four hidden groups of four among sixteen words in a Connections-style daily puzzle — English or Dutch, plus a random practice mode.

22x

≈

/play/snake

Snake

from Games

Eat, grow, do not bite your tail. Solid or wrap-around walls.

24x

▦

/play/tetris

Tetris

from Games

Stack falling blocks and clear lines. Hold and next-piece preview.

29x

9x9

/play/sudoku

Sudoku

from Games

Fill the grid so every row, column and box has 1-9. Hints and check.

25x

⌰

/play/memory

Memory Match

from Games

Flip cards and find the matching pairs in the fewest moves.

27x

WPM

/play/type

Typing Test

from Games

Measure your typing speed and accuracy against a passage.

51x

●

/play/c4

Connect Four

from Games

Drop discs to get four in a row. Two players or vs the computer.

57x

⧉

/play/life

Game of Life

from Games

Conway’s cellular automaton. Paint cells and watch them evolve.

30x

♞

/play/chess

Chess

from Games

Full chess vs the computer or a friend. Castling, en passant, three difficulties.

53x

♣

/play/solitaire

Solitaire

from Games

Classic Klondike — draw 1 or 3, drag or tap, undo and auto-complete.

24x

⊕

/play/battleship

Battleship

from Games

Sink the enemy fleet. Play the computer or a friend over a room code.

61x

▭

/play/breakout

Breakout

from Games

Smash the brick wall with a bouncing ball. Power-ups and multi-hit bricks.

54x

◴

/play/simon

Simon

from Games

Repeat the growing light-and-sound sequence. Strict mode for purists.

24x

15

/play/fifteen

15 Puzzle

from Games

Slide numbered tiles back into order. Three board sizes, timer and best scores.

21x

⌶

/play/hangman

Hangman

from Games

Guess the hidden word letter by letter before the drawing completes. Play solo for streaks, or online with 2-8 friends over a room code — take turns setting a word and guessing.

24x

⏵

/play/flappy

Flappy

from Games

One-button flyer — tap to flap through the gaps. One touch and it is over.

27x

|·|

/play/pong

Pong

from Games

The original. Mouse or W/S against a beatable CPU. First to 7, three difficulties.

44x

▴

/play/asteroids

Asteroids

from Games

Rotate, thrust, and shoot the drifting rocks. Momentum physics, screen wrap, waves.

26x

◑

/play/reversi

Reversi

from Games

Othello — outflank to flip discs. Play the computer or a friend. Three difficulties.

21x

⛀

/play/checkers

Checkers

from Games

American draughts vs the computer, a friend, or online via a room code.

55x

MJ

/play/mahjong

Mahjong Solitaire

from Games

Clear all 144 tiles by matching open pairs. Classic Turtle layout plus Pyramid and Fortress. Every deal is generated solvable.

14x

⌖

/play/doomed

Doomed

from Games

Retro first-person shooter — demons, keycards, secrets and big guns across three sectors.

74x

∿

/play/viper

Stunt Viper

from Games

Pseudo-3D stunt racer — drift, boost and flip off ramps to outrun the clock across four worlds.

42x

▲▲

/play/voxel

Voxel Strike

from Games

Voxel-terrain gunship flyer — skim procedural canyons, thread the rings and strafe ground targets before the clock runs out.

29x

⚘

/play/eco

Ecosystem

from Games

Predator-prey sandbox — grass grows, rabbits graze and breed, foxes hunt. Tune the sliders and watch the populations boom, crash and settle.

56x

▒

/play/sand

Falling Sand

from Games

Element sandbox — paint sand, water, oil, fire, plants and acid onto the canvas and watch the physics play out, grain by grain.

28x

◎

/play/marble

Marble Roll

from Games

Roll a glossy marble through floating sky courses — momentum physics, moving platforms, gems and the clock across six levels.

35x

☉

/play/gravity

Gravity

from Games

2D Newtonian N-body gravity sandbox — drag to slingshot new bodies into orbit, tune gravity and speed, and load solar-system, binary, three-body, galaxy and cluster presets.

24x

×

/play/tables

Times Tables

from Games

Learn your multiplication tables up to 10 or 20 — adaptive practice that repeats what you miss, a 60-second sprint with streak multipliers and a global leaderboard, and a 12-level quest with hearts and stars.

42x

◉

/play/pinball

Pinball

from Games

A solid-state pinball table you play in your browser — plunge, flip and nudge the ball, lock balls for multiball, light the ramps and climb the ranks. Every sound and pixel is generated in code.

34x

↝

/play/drift

Sideways

from Games

Top-down drift arcade in the Absolute Drift style — kick the tail out with the handbrake, hold the slide, chain drifts through the double-pay zones and bank the combo before the two-minute clock runs out. Persistent tire marks, generated sound, global leaderboard.

30x

⎔

/play/windups

Wind-Ups

from Games

A rescue puzzler with original wind-up robots — dig, block, build and float a marching squad safely to the exit hatch across six handcrafted levels.

36x

≋

/play/fluid

Fluid Ink

from Games

A real Navier-Stokes fluid simulation running on your GPU — drag or touch to pour swirling ink, tune vorticity and fade, go fullscreen and zone out.

38x

⁂

/play/horde

Horde Rush

from Games

The crowd-runner the ads promised, for real — a third-person pseudo-3D lane where you steer a growing squad through math gates, melt the zombie horde, shoot the lava pins and take down giant boss zombies. 30 levels, honest upgrades, endless mode with a leaderboard.

43x

⊸

/play/neat

Neuroevolution Lab

from Games

Cars with distance sensors learn to drive by evolving neural networks — a real NEAT algorithm with speciation, live network view and turbo evolution.

37x

✸

/play/bomber

Bomber Arena

from Games

Bomberman-style arena blaster for 1-4 players — solo against bots or online with friends via a room code, blasting through a shrinking sudden-death arena.

59x New

20?

/play/20q

20 Questions

from Games

Think of an animal, a food, a vehicle, an instrument or an everyday object and the computer names it in twenty yes/no questions. It picks each question by information gain and weighs your answers softly, so one slip does not derail the round. When it loses you can teach it, and what you teach stays in this browser.

30x New

⌂

/play/wander

Wander

from Games

An endless procedurally generated world to explore — biomes, day and night, wildlife, and hidden wonders to log in your journal. Find weapons in chests, storm marauder forts and conquer them for better loot, or just keep wandering: the wilderness itself stays peaceful. Tune chest, wonder and fort density with sliders to shape custom worlds, and share a seed to share your exact world.

38x New

★

/play/starbattle

Star Battle

from Games

The Two Not Touch logic puzzle — place stars so every row, every column and every outlined region holds the same number of them, and no two stars ever touch, not even diagonally. Four sizes, region tints, live conflict flagging, hints and a check button. Every puzzle is generated and proved to have exactly one solution in your browser.

31x

€→

/salaris

Gross ↔ Net Salary

from Dutch Tax & Money

Work out your net salary from gross (or the reverse) with the 2024/2025 income-tax brackets, algemene heffingskorting and arbeidskorting.

52x

BTW

/btw

BTW Calculator

from Dutch Tax & Money

Add or extract Dutch VAT (21%, 9% or 0%) from a price including or excluding btw.

24x

B3

/box3

Box 3 Wealth Tax

from Dutch Tax & Money

Estimate your box 3 wealth tax on savings and investments — forfaitair rendement, heffingsvrij vermogen and the fiscal-partner split.

33x

zzp

/zzp

ZZP Net Income & Hourly Rate

from Dutch Tax & Money

Net income for the self-employed after zelfstandigenaftrek and MKB-winstvrijstelling, or the hourly rate you need to hit a target.

41x

30%

/expat

30% Ruling

from Dutch Tax & Money

See the net benefit of the 30% ruling for incoming employees, with the WNT cap and the tiered step-down.

20x

wg€

/employercost

Employer Cost

from Dutch Tax & Money

Total employer cost on top of a gross salary — Awf, Aof, Whk, Zvw premiums and holiday pay.

31x

⌂€

/hypotheek

Mortgage Calculator

from Dutch Tax & Money

Monthly mortgage payments (annuïteit or lineair) with a full schedule, plus an indicative maximum mortgage from your income.

16x

k.k.

/kostenkoper

Buying Costs & Transfer Tax

from Dutch Tax & Money

Add up the buying costs of a home — overdrachtsbelasting (0/2/10.4%), notaris, taxatie, advies and makelaar.

15x

HRA

/hra

Mortgage Interest Deduction

from Dutch Tax & Money

Estimate your mortgage-interest tax deduction — eigenwoningforfait, the capped aftrektarief and the monthly benefit.

45x

TG

/toeslagen

Toeslagen Calculator

from Dutch Tax & Money

Estimate zorgtoeslag, huurtoeslag and kindgebonden budget with the 2026 Dienst Toeslagen formulas.

49x

TV

/transitievergoeding

Transitievergoeding Calculator

from Dutch Tax & Money

Estimate the Dutch statutory severance payment on dismissal: 1/3 gross monthly salary per year of service, pro-rated by day, capped at the 2026 statutory maximum.

76x

AOW

/aow

AOW Age & Pension

from Dutch Tax & Money

Find your AOW age and date, the monthly AOW amount, and a rough pension-gap estimate.

1.1kx

DUO

/studieschuld

Student Debt (DUO)

from Dutch Tax & Money

Monthly repayment of a DUO student debt over 15 or 35 years, with total interest and payoff date.

23x

%↑

/inflatie

Inflation & Purchasing Power

from Dutch Tax & Money

See what an amount is worth in another year using the CBS inflation series — cumulative and average.

52x

€↗

/invest

Investing & Recurring Contributions

from Money & Finance

Project investment growth with monthly contributions — nominal and inflation-adjusted, year by year.

40x

FI

/fire

FIRE Calculator

from Money & Finance

Your financial-independence number and how many years to reach it, with coast-FIRE.

58x

÷€

/split

Tip & Bill Splitter

from Money & Finance

Split a bill between people and add a tip — even or rounded up per person.

21x

BMI

/bmi

BMI, TDEE & Body Fat

from Health & Body

BMI with WHO categories, Mifflin-St Jeor daily calorie needs (cut/maintain/bulk), and the US Navy tape-measure body-fat method. Adults only, not medical advice.

47x

⇥

/share

Share Receiver

from Share & Store

Receives text and files shared from other apps on your Android device via the 1234.nu app, and turns them into a paste, short link, or upload.

✸

/learn

All explainers

from Learn

Interactive visual explainers — how an LLM, the JVM, TypeScript, HTTPS, Git, DNS, and WebRTC actually work.

API

/api

API & MCP

from Reference

Call these tools programmatically over a plain REST API, or connect them to an MCP client like Claude.

APK

/app

1234.nu Android App

from Reference

A thin companion app that unlocks background screen recording, live location, exact alarms, real lux readings, and Waveshare e-paper NFC writing — the APK downloads straight from this site, no Play Store needed.

▶

/play

All games

from Games

The arcade — all games on one page.