✸Learn
Interactive visual explainers of how the tech works. · 7 tools
No tools match.
Share & Store
>_
/p
Paste
from Share & Store
Share code with syntax highlighting. Raw view, burn-after-read.
117x
[ ]
/s
Share
from Share & Store
Drop a file, get a link. Up to 100 MB. Auto-expires.
118x
###
/n
Note
from Share & Store
Write a note in Markdown with live preview, then share a link. No account needed.
77x
¶
/r
Rich Note
from Share & Store
Publish a formatted note with a visual rich-text editor. No account needed.
50x
[*]
/i
Image
from Share & Store
Upload or paste an image. Direct link, embed codes.
165x
->
/u
URL
from Share & Store
Shorten any URL. Custom slugs, click stats, optional TTL.
73x
[*]
/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.
69x
⧉
/clip
Clipboard Sync
from Share & Store
Send text between your devices with a 6-digit code. Relayed live, never stored.
68x
<=
/hook
Webhook Tester
from Share & Store
Get a URL that captures every request sent to it. Inspect method, headers, body live.
60x
|||
/poll
Poll
from Share & Store
Anonymous polls with live results. Single or multiple choice, no IPs stored.
65x
?=
/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.
59x
◉
/call
Video Call
from Share & Store
Quick group video + voice call over a room code. Peer-to-peer, nothing recorded.
63x
✎
/board
Shared Whiteboard
from Share & Store
Sketch together in real time over a room code. Strokes and sticky notes relayed live, never stored.
73x
◎
/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.
46x
Encode & Decode
⚒
/forge
Forge
from Encode & Decode
Chain operations into a recipe — encode, hash, compress, cipher, reshape text — step by step in your browser.
105x
64
/b64
Base64 / 32 / Hex
from Encode & Decode
Encode or decode text as Base64, Base32, hex, Base58, or z85.
42x
%
/urlencode
URL Encode
from Encode & Decode
Percent-encode or decode URL components. Live sync.
64x
&
/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.
88x
{.}
/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.
93x
[z]
/gz
Gzip / Brotli / Zstd
from Encode & Decode
Compress or decompress text with gzip, deflate, brotli, or zstandard. Shows size difference.
71x
[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.
31x
01
/bin
Text ↔ Binary
from Encode & Decode
Convert text to and from 8-bit binary. UTF-8 bytes, space separated.
33x
↻
/rot
ROT13 / Caesar
from Encode & Decode
Apply a ROT13, Caesar, ROT47, or Atbash cipher to text.
70x
d:
/datauri
Data URI
from Encode & Decode
Turn a file or text into a data: URI, or decode one back. Stays in your browser.
32x
U+
/uni
Unicode Inspector
from Encode & Decode
Break text into code points — U+ value, decimal, HTML entity, UTF-8 bytes.
36x
xn--
/punycode
Punycode / IDN
from Encode & Decode
Convert internationalized domain names to punycode and back.
42x
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.
66x
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.
46x
Data & Config
{}
/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.
41x
{+}
/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.
41x
,[]
/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.
32x
$x=
/env
.env Parser
from Data & Config
Paste a .env file and inspect the parsed key-value pairs.
79x
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.
583x
{≠}
/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.
30x
▦
/jtable
JSON → Table
from Data & Config
Turn a JSON array into a sortable, filterable table. Export Markdown or CSV.
64x
▨
/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.
62x
dc
/compose
docker run → Compose
from Data & Config
Paste a docker run command and get an equivalent docker-compose.yml service.
75x
⇄:
/proxygen
Reverse Proxy Config
from Data & Config
Generate Nginx, Caddy, and Traefik reverse-proxy config from one form — HTTPS, WebSockets, HSTS, basic auth.
64x
☎
/phone
Phone Number Parser
from Data & Config
Parse a phone number to E.164 and detect its country and dialling code.
31x
◈
/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.
24x
cc:
/commitlint
Commit Linter
from Data & Config
Check a commit message against Conventional Commits — type, scope, breaking change, and the semver bump it implies.
27x
v1.2
/semver
Semver Calculator
from Data & Config
Compare semantic versions, test range satisfaction (^ ~ x-ranges hyphen ||) and compute the next bump.
62x
{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.
30x
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.
66x
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.
30x
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.
63x
Text
+-
/diff
Diff
from Text
Compare two text blocks line-by-line, or create and apply a unified-diff patch.
59x
.*
/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.
33x
aA_
/case
Case Converter
from Text
Convert identifiers between camelCase, snake_case, PascalCase, kebab-case, and more.
75x
str
/str
String Ops
from Text
Reverse, trim, pad, repeat, number lines, and remove blank/duplicate lines.
65x
A-Z
/sort
Sort / Filter
from Text
Sort lines alphabetically, numerically, or by length. Remove duplicates.
27x
Σ
/text
Text Stats
from Text
Word, character and line counts, reading time, and word frequency.
87x
**
/md
Markdown
from Text
Write Markdown, preview the rendered HTML output.
88x
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.
27x
a-b
/slug
Slugify
from Text
Turn any text into a clean, URL-safe slug. Accents stripped, spaces collapsed.
71x
¶✕
/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.
45x
|-|
/mdtable
Markdown Table
from Text
Turn CSV or TSV data into an aligned Markdown table.
30x
</>
/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.
25x
<>↓
/htmlmd
HTML → Markdown
from Text
Convert HTML into clean Markdown, live in your browser.
25x
<>@
/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.
26x
<jsx
/jsx
HTML → JSX
from Text
Paste HTML, get JSX — className, style objects, camelCased attributes, self-closed tags.
61x
@↓
/emailnorm
Email Normalizer
from Text
Canonicalize emails — lowercase, strip Gmail dots and +tags — then dedupe a list.
65x
Run Code
>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.
46x
jav
/java
Java Sandbox
from Run Code
Run small Java programs with a built-in interpreter. Nothing leaves your browser.
28x
wsm
/wasm
WebAssembly Runner
from Run Code
Load, inspect, instantiate and call .wasm modules right in your browser.
60x
AI & Prompts
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.
71x
[..]
/chatjson
Chat Message Builder
from AI & Prompts
Build a conversation and export the JSON body for the Claude or OpenAI chat APIs.
59x
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.
83x
!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
Agile & Scrum
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
Crypto & Passwords
#
/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.
29x
h()
/hmac
HMAC
from Crypto & Passwords
Generate an HMAC signature with SHA-256, SHA-384, SHA-512, or SHA-1 — entirely in your browser.
58x
***
/pass
Password
from Crypto & Passwords
Generate random passwords, EFF diceware passphrases, PINs and pronounceable passwords, and check password strength.
45x
id
/uuid
UUID / ULID
from Crypto & Passwords
Generate UUID v4, time-ordered v7, name-based v5 or ULID identifiers — and decode any UUID.
41x
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.
28x
AES
/aes
AES Text Encryption
from Crypto & Passwords
Encrypt or decrypt text with a passphrase (AES-256-GCM). Stays in your browser.
31x
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.
45x
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.
22x
h:p
/htpasswd
Basic Auth / htpasswd
from Crypto & Passwords
Build an HTTP Authorization: Basic header and .htpasswd lines, in your browser.
18x
Numbers & Math
0x
/baseconv
Base Convert
from Numbers & Math
Convert integers between decimal, binary, hex, and octal.
48x
1,2k
/num
Number Format
from Numbers & Math
Format numbers with commas, words, hex, binary, and scientific notation.
65x
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.
60x
17
/prime
Primes & Factors
from Numbers & Math
Primality check, prime factorization, and next/previous prime.
27x
x̄σ
/stats
Number Stats
from Numbers & Math
Mean, median, mode, standard deviation, and percentiles of a number list.
52x
∿
/plot
Function Plotter
from Numbers & Math
Plot mathematical functions of x. Pan, zoom, multiple curves.
45x
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.
68x
nCr
/comb
Combinatorics
from Numbers & Math
Factorials, permutations, and combinations — exact big-integer results.
73x
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.
157x
%+
/finance
Finance Calculator
from Numbers & Math
Compound interest & savings growth, plus loan payments and a full amortization schedule.
65x
f(
/eval
Math Evaluator
from Numbers & Math
Type a math expression and get the result — functions, constants, factorial.
58x
&|^
/bit
Bitwise Calculator
from Numbers & Math
AND, OR, XOR, NOT and shifts across decimal, hex, octal and binary.
60x
fl
/float
Float Inspector
from Numbers & Math
See how a number is stored as an IEEE-754 float — sign, exponent, mantissa.
65x
△
/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.
53x
Electronics
ΩVI
/ohm
Ohm's Law
from Electronics
Enter any two of voltage, current, resistance, or power — get the other two, with the formula used.
52x
▮▮▮
/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.
63x
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.
24x
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.
26x
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.
62x
Xc
/react
Reactance & Resonance
from Electronics
Capacitive and inductive reactance at a frequency, and the resonant frequency of an LC circuit.
22x
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.
25x
▷∞
/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.
55x
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.
59x
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.
52x
⊓⊔
/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.
20x
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.
31x
⇆
/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.
65x
Radio & RF
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.
19x
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
IoT & Protocols
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.
50x
◧
/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.
55x
⌹
/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.
64x
(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.
39x
Energy
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.
27x
ΣA
/peakload
Peak Load
from Energy
Add up appliances running at once and check the total current against your main fuse or breaker.
128x
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
Fabrication
⊚
/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.
19x
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.
23x
◳
/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
Outdoors & Sky
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.
25x
Td
/dewpoint
Dew Point
from Outdoors & Sky
Dew point from temperature and humidity (Magnus formula), with a mugginess comfort scale.
58x
~°
/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.
25x
✷
/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.
23x
⚑
/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.
45x
Date & Time
>>
/epoch
Timestamp
from Date & Time
Convert between Unix timestamps and human-readable dates.
83x
TZ
/tz
Timezone Converter
from Date & Time
Convert a datetime between any two IANA timezones.
47x
◷
/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.
35x
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.
62x
(@)
/cron
Cron
from Date & Time
Parse a cron expression. Get a plain-English description and next 5 run times.
58x
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.
23x
*id
/snowflake
ID Timestamp Decoder
from Date & Time
Extract the date from Discord/Twitter snowflakes, ULIDs, UUIDs, ObjectIds, unix stamps.
19x
[#]
/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.
37x
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.
46x
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.
21x
Web & Design
●
/color
Color
from Web & Design
Convert between HEX, RGB, HSL, HSV, OKLCH, OKLab, CIE Lab, and CMYK. Live preview swatch.
52x
◐
/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.
39x
▣
/shadow
Box Shadow
from Web & Design
Layered CSS box-shadow builder with live preview.
63x
rem
/px
px ↔ rem
from Web & Design
Convert px, rem, em, pt, and % with a configurable base size.
68x
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.
60x
⬡
/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.
48x
◑
/cvd
Color-Blindness Simulator
from Web & Design
See how an image or palette looks with protan, deutan, or tritan color vision.
66x
⤳
/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.
33x
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.
50x
∫
/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.
46x
"
/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.
23x
LOL
/meme
Meme Generator
from Web & Design
Drop an image, add captions, images and emojis, then download or share the meme. All client-side.
53x
◳
/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.
67x
▦
/grid
CSS Grid Generator
from Web & Design
Design a CSS grid with a live preview — columns, rows, gaps — and copy the code.
26x
▢
/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.
17x
◎
/illusion
Optical Illusion
from Web & Design
Generate static optical illusions that seem to shimmer or bend — scintillating grid, Hermann grid, café wall. Export PNG.
64x
#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.
20x
⬭
/blob
Blob & Border-Radius
from Web & Design
Sculpt organic shapes — fancy 8-value border-radius CSS or a smooth random SVG blob to download.
22x
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.
58x
Network
~~~
/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.
45x
: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.
23x
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.
26x
MAC
/mac
MAC Address Tools
from Network
Generate random MAC addresses or look up the vendor (OUI) behind one.
54x
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.
66x
?×
/clean
URL Cleaner
from Network
Unwrap redirect-wrapped links (SafeLinks, Google, Proofpoint) and strip tracking parameters.
24x
Generate
::
/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.
45x
f@k
/fake
Fake Data
from Generate
Generate test data — names, personas, companies, KVK/BSN/IBAN; export JSON, SQL or Postgres COPY.
55x
?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.
52x
.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.
18x
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.
53x
Learn
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.
23x
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.
20x
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
Reference
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.
31x
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.
53x
rwx
/chmod
Chmod
from Reference
Toggle Unix permission bits and get the numeric octal value instantly.
77x
:)
/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
Device Tests
[o]
/cam
Webcam Test
from Device Tests
Check your camera — live preview, resolution, frame rate, switch devices, snapshot. Nothing is uploaded.
24x
))
/mic
Microphone Test
from Device Tests
Test your mic — live input level, waveform, peak meter and device picker. Nothing is recorded.
25x
⌨
/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.
59x
[¦]
/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.
21x
▦
/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.
19x
[+:]
/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.
46x
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.
60x
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.
68x
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.
85x
Sensors & Signals
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.
65x
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
Music & Audio
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.
20x
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.
18x
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.
40x
Media
[>]
/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.
25x
[>]
/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.
26x
♪✕
/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.
48x
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.
31x
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.
44x
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.
30x
(●)
/rec
Screen, Webcam & Audio Recorder
from Media
Record your screen, webcam, or microphone-only to a file, right in your browser. Nothing is uploaded.
46x
A→
/ocr
Image OCR
from Media
Extract text from an image, screenshot, scan or photo — locally in your browser with Tesseract. Nothing is uploaded.
36x
◎?
/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.
23x
[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.
11x
Fun
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.
28x
𝓐a
/fancy
Text Styler
from Fun
One input, every style — Unicode fonts, flip/mirror, mocking caps, leet, zalgo, noisy, typoglycemia, numeronym. All client-side.
74x
2d6
/dice
Dice Roller
from Fun
Roll dice with NdM+K notation and see the exact odds of every outcome. Cryptographically random.
29x
#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.
26x
(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.
16x
#/
/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.
27x
♪♫
/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.
63x
✺
/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.
29x
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
Games
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.
23x
≈
/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.
29x
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.
54x
♣
/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
Dutch Tax & Money
€→
/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.
25x
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.
34x
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.
46x
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
Money & Finance
€↗
/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.
59x
÷€
/split
Tip & Bill Splitter
from Money & Finance
Split a bill between people and add a tip — even or rounded up per person.
22x
Health & Body
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.
48x
⇥
/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.
Missing a tool? Let us know what you need.