Open source
Credits
Many of the tools here stand on open source projects that people built and shared for free. This page names them: what each one is, what it does on this site, and which tools would not exist without it. Go star them, sponsor them, or just enjoy their work.
@peculiar/x509
An X.509 certificate library built on the Web Crypto API. Parses certificates and key details in the Certificate Decoder.
Ajv
The most widely used JSON Schema validator for JavaScript. Does the actual validating in the JSON Schema Validator.
brotli-wasm
Google's Brotli compression, compiled to WebAssembly. Handles the Brotli side of the compression tools.
bwip-js
A barcode writer that can draw over a hundred barcode types. Renders every barcode the Barcode Generator offers.
CodeMirror
The extensible code editor for the web. Every code and text editing pane on this site is a CodeMirror editor.
Used all over the site.
exifr
A fast and versatile EXIF and photo metadata parser. Reads the metadata out of photos in the EXIF tools.
Faker
A generator for realistic fake data, from names and addresses to bank accounts. Produces all the sample data in the Fake Data Generator.
ffmpeg.wasm
A WebAssembly build of FFmpeg, the audio and video toolkit behind half the media software you know. Converts audio, trims tracks, pulls frames out of videos and stitches frames into clips.
hash-wasm
Hand-tuned WebAssembly implementations of MD5, SHA, BLAKE, bcrypt, Argon2 and many more. Computes the site's hashes, checksums and password digests at near-native speed.
jose
A complete JavaScript implementation of JWT, JWS, JWE and the rest of the JOSE family. Verifies token signatures in the JWT Decoder.
jq
The command-line JSON processor, a whole little language for slicing and transforming JSON. Runs your filters in the jq Playground as the real jq, compiled to WebAssembly.
jsdiff
A JavaScript implementation of the classic Myers diff algorithm. Computes the differences shown in the text and JSON diff tools.
JSONPath Plus
A JSONPath implementation with the extensions people actually use. Evaluates your queries in the JSONPath Playground.
jsQR
A pure JavaScript QR code reader. Finds and decodes the QR codes in images you drop into the scanner.
mediainfo.js
A WebAssembly port of MediaInfo, the classic tool for revealing what is inside a media file. Digs the codec, stream and format details out of video files.
music-metadata
A metadata parser that understands the tags of virtually every audio format. Reads the tags, cover art and technical details of audio files.
node-qrcode
A QR code encoder for JavaScript. Turns your text and links into the QR codes the generator draws.
pdf-lib
A library for creating and modifying PDF documents in pure JavaScript. Builds, merges, splits and rewrites the PDFs the PDF tools produce.
PDF.js
Mozilla's PDF renderer, the same engine that displays PDFs in Firefox. Renders PDF pages into the images and previews the PDF tools show.
piexifjs
A library for reading and writing the EXIF data inside JPEG files. Writes edited metadata back into your photos.
pixelmatch
A small and precise pixel-level image comparison library. Spots the changed pixels in the Image Diff.
Prettier
The opinionated code formatter used across the JavaScript ecosystem. Formats most of the languages in the Code Formatter.
SQL Formatter
A formatter for SQL in all its many dialects. Formats the SQL dialects in the Code Formatter.
SVGO
The standard optimizer for SVG files. Does the actual cleanup in the SVG Optimizer.
Tesseract.js
A WebAssembly port of the Tesseract OCR engine, able to read text in over 100 languages. Reads the text out of images in the Image to Text tool.
UAParser.js
The user agent parser behind countless detection and analytics setups. Breaks user agent strings down in the User Agent Parser.
zstd-wasm
A WebAssembly build of Zstandard, the fast modern compression format. Handles the Zstandard side of the compression tools.
A tool's own page also names the projects it is built on, right at the end of its article.