Free developer tools
110 quick tools for code, data, images, PDFs and more. They run in your browser, so your files and text stay on your device.
JSON & Data 8 tools
JSON Formatter
Format, validate, minify and sort JSON with exact error positions.
Open toolYAML ⇄ JSON Converter
Convert YAML to JSON and JSON to YAML, with validation and clear error messages.
Open toolCSV to JSON Converter
Turn CSV into JSON (arrays or objects) and back, with delimiter and header options.
Open toolJSON to CSV Converter
Flatten JSON arrays into CSV, pick the columns you want and download the file.
Open toolJSON Schema Validator
Validate JSON against a JSON Schema (draft-07 or 2020-12) with readable error paths.
Open toolJSON to TypeScript
Generate TypeScript interfaces or types from a JSON sample, including nested objects.
Open toolJSON ⇄ TOON Converter
Convert JSON to TOON (Token-Oriented Object Notation) to cut LLM prompt tokens, and back.
Open toolXML Formatter
Pretty-print, minify and validate XML, with the line of any syntax error.
Open toolText & Writing 10 tools
Case Converter
Convert text to UPPER, lower, Title, Sentence and more in one click.
Open toolText Diff Checker
Compare two texts and highlight added, removed and changed lines or words.
Open toolWord & Character Counter
Count words, characters, sentences and paragraphs, with reading time, readability and keyword density.
Open toolLorem Ipsum Generator
Generate placeholder paragraphs, sentences, words or list items, as text or HTML.
Open toolString Utilities
Trim, reverse, sort, dedupe, slugify, escape and transform text with one click.
Open toolMarkdown to HTML
Convert Markdown (GitHub-flavoured) to clean HTML with a live preview.
Open toolMarkdown Table Generator
Build Markdown tables in a grid editor or from CSV, with column alignment and preview.
Open toolUnicode Character Finder
Search thousands of Unicode characters by name or code point and copy them in any format.
Open toolText to Speech
Read text aloud with your device’s voices, with adjustable speed, pitch and volume.
Open toolTodo List
A simple, private task list that remembers your work between visits.
Open toolEncoding & Hashing 9 tools
Base64 Encoder
Encode and decode Base64 text and files, with full Unicode and URL-safe support.
Open toolBase64 Image Encoder
Convert images to Base64 data URLs (with CSS and HTML snippets) and decode them back.
Open toolHTML Entity Encoder / Decoder
Escape text to HTML entities (named, decimal or hex) and decode entities back to text.
Open toolURL Parser & Encoder
Break a URL into its parts and query parameters, encode or decode it, and flag risky patterns.
Open toolNumber Base Converter
Convert numbers between binary, octal, decimal, hex and any base from 2 to 36 — even huge ones.
Open toolHash Generator
Generate MD5, SHA, PBKDF2 and Bcrypt hashes right in your browser.
Open toolUUID Generator
Generate UUID v1, v3, v4, v5 and v7 in bulk, and validate or inspect existing UUIDs.
Open toolJWT Decoder
Inspect a JSON Web Token’s header, payload and expiry.
Open toolJWT Expiry Checker
Check whether a JWT is expired, not yet valid or about to expire, with a live countdown.
Open toolSecurity 6 tools
Password Generator
Create strong random passwords or passphrases with entropy and crack-time estimates.
Open toolPassword Strength Tester
See how strong a password really is, what makes it weak and how to improve it.
Open toolBcrypt Hash Generator
Hash passwords with bcrypt at any cost factor and verify a password against a hash.
Open toolSSL Certificate Decoder
Decode a PEM certificate to see its subject, issuer, validity, SANs, key and fingerprints.
Open toolEnvironment Variable Validator
Check env vars for leaked secrets, weak values, missing required keys and naming problems.
Open toolJavaScript Obfuscator
Make JavaScript harder to read with mangled names, encoded strings and compacted code.
Open toolCode Tools 12 tools
HTML Editor
Write HTML and preview it live, with formatting, import and export.
Open toolRegex Tester
Test regular expressions with live highlighting and capture groups.
Open toolRegex Pattern Builder
Assemble a regular expression from building blocks and test it against your text as you go.
Open toolRegex Explainer
Break any regular expression into plain-English pieces, token by token.
Open toolPlain-English Regex Generator
Describe what to match in plain English and get a ready-to-use, tested regex.
Open toolCode Linter
Find syntax errors and common problems in JavaScript, JSON, CSS, HTML and Python.
Open toolCode Diff Generator
Create a unified diff (patch) between two versions of code, ready for git apply.
Open toolCode Comment Generator
Generate JSDoc, Python docstring and PHPDoc blocks from your function signatures.
Open toolJavaScript Minifier
Minify JavaScript with Terser (compress + mangle) or beautify it, and see the bytes saved.
Open toolHTML Formatter
Beautify messy HTML with Prettier or minify it for production.
Open toolSQL Formatter
Format SQL for MySQL, PostgreSQL, SQL Server, SQLite and more, with keyword casing options.
Open toolPerformance Score Calculator
Calculate a Lighthouse-style performance score from your metrics and see what to fix first.
Open toolCSS & Color 12 tools
Color Contrast Analyzer
Check WCAG AA/AAA contrast and get the nearest accessible colour suggestions.
Open toolCSS Color Contrast Checker
Paste CSS and check every text/background colour pair against WCAG at once.
Open toolColor Palette Generator
Generate harmonious colour palettes and export them as CSS variables, SCSS or JSON.
Open toolColor Converter
Convert colours between HEX, RGB, HSL, HSV, CMYK and CSS names instantly.
Open toolCSS Grid Generator
Design grid layouts visually — columns, rows, gaps and spans — and copy the CSS.
Open toolCSS Flexbox Generator
Try direction, wrap, justify and align on live items and copy the flexbox CSS.
Open toolCSS Box Shadow Generator
Layer multiple box-shadows with sliders and a live preview, then copy the CSS.
Open toolCSS Gradient Generator
Build linear, radial and conic gradients with multiple colour stops.
Open toolCSS Border Radius Generator
Shape each corner (even elliptical radii) visually and copy the border-radius CSS.
Open toolCSS Loader Generator
Pick a pure-CSS spinner, tweak size, colour and speed, and copy the HTML and CSS.
Open toolCSS Minifier & Beautifier
Minify CSS to save bytes or beautify it for reading, with a size comparison.
Open toolCSS Validator
Find syntax errors, unknown properties, suspicious values and duplicate declarations in CSS.
Open toolImage Tools 11 tools
Image Compressor
Shrink JPG, PNG and WebP images in your browser with a quality slider and before/after sizes.
Open toolImage Resizer
Resize or crop images by pixels or percentage, keep the aspect ratio, export JPG, PNG or WebP.
Open toolPNG to JPG Converter
Convert PNG (and WebP) images to JPG in bulk, with a background colour for transparency.
Open toolHEIC to JPG Converter
Convert iPhone HEIC/HEIF photos to JPG or PNG without uploading them anywhere.
Open toolImage to Text (OCR)
Extract text from screenshots, photos and scans with in-browser OCR in many languages.
Open toolQR Code Generator
Create QR codes for links, text, Wi-Fi, contacts, email and SMS; download PNG or SVG.
Open toolQR Code Reader
Scan QR codes from an image file, a pasted screenshot or your camera.
Open toolFavicon Generator
Make favicons from text, emoji or an image: every size, an .ico file and the HTML tags.
Open toolSVG Optimizer
Optimise SVG with SVGO (or pretty-print it) and compare the result before and after.
Open toolASCII Art Generator
Turn images into ASCII art with adjustable width, character sets and inversion.
Open toolColor Extractor
Pull the dominant colour palette out of any image and copy the HEX codes.
Open toolPDF Tools 5 tools
PDF Merger
Combine several PDFs into one, in the order you choose — all in your browser.
Open toolPDF Splitter
Extract page ranges or split every page of a PDF into separate files.
Open toolPDF Compressor
Reduce PDF size by re-saving efficiently or by rendering pages as compressed images.
Open toolPDF to JPG
Convert PDF pages to JPG or PNG images at the resolution you need.
Open toolJPG to PDF
Combine JPG and PNG images into a single PDF with page size and margin options.
Open toolAPI & HTTP 8 tools
cURL to Code
Convert cURL commands into fetch, Axios, Python requests, PHP, Go and Node.js code.
Open toolHTTP Request Builder
Build a request with params, headers, auth and body, send it, and export it as cURL or fetch.
Open toolAPI Endpoint Tester
Hit an endpoint repeatedly and measure min, average and p95 response times and success rate.
Open toolAPI Response Tester
Send a request and assert on status, headers, JSON fields and response time.
Open toolHTTP Headers Analyzer
Paste response headers to grade security headers, caching and CORS, with fixes.
Open toolHTTP Status Codes
Look up every HTTP status code with its plain-English meaning and when to use it.
Open toolCache-Control Builder
Build a Cache-Control header from presets or directives and see what each one does.
Open toolAPI Docs Generator
Turn an OpenAPI/Swagger spec (JSON or YAML) into readable HTML or Markdown docs.
Open toolNetwork 3 tools
DNS Lookup
Query A, AAAA, MX, TXT, CNAME, NS and other records over DNS-over-HTTPS.
Open toolWHOIS / RDAP Lookup
See a domain’s registrar, creation and expiry dates, status and name servers via RDAP.
Open toolIP Subnet Calculator
Calculate network, broadcast, host range and mask for IPv4 CIDR blocks, and split subnets.
Open toolDevOps & Git 10 tools
Cron Helper
Explain cron schedules in plain English and see the next runs.
Open toolDocker Compose Generator
Build a docker-compose.yml from service presets with ports, volumes, env and dependencies.
Open toolDocker Compose Validator
Validate docker-compose.yml syntax and structure and catch broken references.
Open toolDockerfile Generator
Generate a production-ready, multi-stage Dockerfile for Node, Python, Go, Java, PHP and more.
Open toolEnv File Parser
Parse .env files into JSON, YAML, shell exports or Docker/Kubernetes formats, with error checks.
Open tool.gitignore Generator
Combine .gitignore templates for languages, frameworks, editors and operating systems.
Open toolGit Branch Visualizer
Type git commands (commit, branch, checkout, merge) and watch the branch graph draw itself.
Open toolCommit Message Improver
Turn rough commit messages into clean Conventional Commits, with a lint report.
Open toolGitHub Repo Health Checker
Score a public GitHub repository on activity, docs, community files and README quality.
Open toolpackage.json Analyzer
Audit a package.json for risky versions, missing fields, duplicate deps and script issues.
Open toolSEO & Web 3 tools
Meta Tags Generator & Preview
Write title, description and Open Graph tags and preview them on Google, Facebook, X and LinkedIn.
Open toolrobots.txt Generator
Create a robots.txt with per-bot rules, AI crawler blocking, crawl-delay and sitemaps.
Open toolHTML Table Generator
Create HTML tables from CSV or a grid editor, with header, caption and style options.
Open toolCalculators 10 tools
Unit Converter
Convert length, weight, temperature, volume, area, speed, time and data units.
Open toolFile Size & Transfer Calculator
Convert between bytes, KB/KiB, MB/MiB and more, and estimate download time at any speed.
Open toolTimestamp Converter
Convert Unix timestamps (seconds or ms) to dates and back, across time zones and formats.
Open toolAge Calculator
Find an exact age in years, months and days, plus a next-birthday countdown.
Open toolBMI Calculator
Calculate Body Mass Index in metric or imperial units and see the healthy weight range.
Open toolCompound Interest Calculator
Project investment growth with compounding and monthly contributions, year by year.
Open toolDate Calculator
Count days between dates (including business days) or add and subtract time from a date.
Open toolLoan / EMI Calculator
Work out the monthly payment, total interest and full amortization schedule of a loan.
Open toolPercentage Calculator
Solve every percentage question: X% of Y, percent change, increase, decrease and more.
Open toolTip Calculator
Calculate the tip and split the bill between any number of people.
Open toolGenerators 3 tools
Random Data Generator
Generate mock users, addresses, numbers and more as JSON, CSV or SQL inserts.
Open toolBusiness Name Generator
Get brandable startup and business name ideas from your keywords, in the style you choose.
Open toolPlan Maker
Draft a structured business, project or marketing plan from a few answers, ready to edit.
Open tool