All 125 developer tools
Every tool runs entirely in your browser — nothing you paste is uploaded, and there's no account to create. Jump to a category, or browse the full list below.
Code Formatters & Beautifiers
About format tools →JSON Formatter
Format, validate and minify JSON instantly
NDJSON / JSON Lines Formatter & Validator
Validate and pretty-print newline-delimited JSON, or convert to/from a regular JSON array
Markdown Preview
Write and preview Markdown in real time
SQL Formatter
Format or minify SQL across 14 dialects, including SQL Server, Oracle, and Snowflake
HTML Formatter
Prettify and minify HTML markup instantly
Word Counter
Count words, characters, sentences, and estimate reading time
SVG Optimizer
Strip editor cruft and shrink SVG file size — entirely in your browser
Image Compressor
Compress and resize JPEG, PNG, and WebP images entirely in your browser
Image EXIF Viewer & Remover
See exactly what metadata is embedded in a photo — camera info, timestamp, GPS location — and strip it before sharing
GraphQL Query Formatter
Format and minify GraphQL queries, mutations, and fragments
XML Formatter
Prettify, minify, and validate XML with CDATA-safe formatting
List Sorter & Deduplicator
Sort, dedupe, shuffle, and clean up lists of text lines
JavaScript / TypeScript Formatter & Minifier
Beautify or minify JS and TS code instantly — powered by Prettier and Terser
Encoders & Decoders
About encode tools →Base64 Encoder/Decoder
Encode or decode Base64 strings instantly
URL Encoder/Decoder
Encode and decode URLs and query parameters
JWT Decoder
Decode and inspect JWT tokens instantly
Hash Generator
Generate MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes and HMACs
HTML Entity Encoder
Encode and decode HTML entities and special characters
Image to Base64
Convert images to Base64 data URIs for embedding
Base58 Encoder / Decoder
Encode or decode Base58 strings — the Bitcoin-style alphabet that skips ambiguous characters
Base32 Encoder / Decoder
Encode or decode RFC 4648 Base32 strings — the format behind TOTP secrets and DNSSEC
Base62 Encoder / Decoder
Encode or decode Base62 strings — the alphanumeric-only alphabet behind short URL slugs
Developer Generators
About generate tools →Lorem Ipsum Generator
Generate placeholder text for your designs
Password Generator
Generate strong, random passwords with custom rules
UUID Generator
Generate RFC 4122 v4 UUIDs in bulk
ULID Generator
Generate sortable, URL-safe ULIDs in bulk — a 48-bit timestamp plus 80 bits of randomness
JSON to TypeScript
Auto-generate TypeScript interfaces from JSON objects
JSON to Zod Schema Generator
Paste sample JSON and get a ready-to-use Zod schema plus its inferred TypeScript type
QR Code Generator
Generate QR codes from any URL or text
QR Code Scanner / Decoder
Upload a QR code image and decode exactly what it contains — including 2FA otpauth:// secrets
JWT Generator
Create and sign JWTs with custom claims in-browser
Git Command Generator
Find and copy git commands fast — search, filter by category, with warnings
Markdown Table Generator
Build Markdown tables visually — edit cells, align columns, export as HTML
Markdown Table of Contents Generator
Generate an anchor-linked table of contents from markdown headings — GitHub-style slugs
Meta Tags Generator
Generate Open Graph, Twitter Card, and SEO meta tags with live previews
Favicon Generator
Upload one image and get every favicon size your site needs
Fake Data Generator
Define a schema and generate realistic mock JSON or CSV data
.gitignore Generator
Pick your stack and get a ready-to-use .gitignore instantly
JSON Schema Generator
Infer a JSON Schema (draft-07) from a sample JSON object
Slug Generator
Turn titles into clean, URL-safe slugs — batch supported
robots.txt Generator
Build a robots.txt with per-bot rules, AI crawler blocking, and sitemap links
XML Sitemap Generator
Paste your page URLs and get a ready-to-upload sitemap.xml
Barcode Generator
Generate Code 128, EAN-13, and UPC-A barcodes — download as PNG
README Badge Generator
Build shields.io badges for your README — custom text badges or live repo stats
Open Source License Generator
Pick a license, fill in your name, get a ready-to-commit LICENSE file
GitHub Actions Workflow Generator
Pick a stack and triggers, get a ready-to-commit .github/workflows YAML file
Format Converters
About convert tools →Color Converter
Convert between HEX, RGB, and HSL color formats
Timestamp Converter
Convert Unix timestamps to human-readable dates
Number Base Converter
Convert numbers between binary, octal, decimal, and hex
String Case Converter
Convert text between camelCase, snake_case, kebab-case and more
JSON ↔ YAML Converter
Convert between JSON and YAML formats instantly
IP / CIDR Calculator
Calculate subnet masks, IP ranges, and host counts from CIDR notation
Docker Run to Compose
Convert docker run commands to docker-compose.yml and back
Dockerfile Generator
Pick a stack and get a sensible, multi-stage-aware Dockerfile — plus a matching .dockerignore
CSV to JSON Converter
Convert CSV to JSON instantly, or JSON back to CSV
XML ↔ JSON Converter
Convert between XML and JSON formats instantly, in either direction
Env File Tool
Parse, convert, and generate .env.example files from your .env
cURL to Code
Paste a curl command, get working code in JavaScript, Python, PHP, or Go
URL Parser & Query String Builder
Break down a URL into its parts and build query strings visually
.htaccess to Nginx Converter
Convert Apache .htaccess rules to nginx server block syntax
Meeting Planner
Compare working hours across time zones and find a meeting time that works for everyone
JSON to Markdown Table
Convert a JSON array of objects into a ready-to-paste Markdown table
SVG to JSX / React Component
Paste raw SVG markup and get a ready-to-use React component
Database Connection String Parser & Builder
Parse a Postgres, MySQL, MongoDB, or Redis connection URI into its parts — or build one visually
Testers & Validators
About test tools →Regex Tester
Test and debug regular expressions with live highlighting
Diff Checker
Compare two texts and highlight differences
CRON Expression Tester
Parse cron expressions and preview upcoming run times
HTTP Request Builder
Build and send HTTP requests like a lightweight Postman
WebSocket Tester
Connect to any ws:// or wss:// endpoint, send messages, and watch a live, timestamped log
SemVer Calculator & Range Checker
Test versions against npm ranges like ^1.2.3 or ~2.0, compare versions, and preview version bumps
YAML / TOML / JSON Validator
Validate and convert between YAML, TOML, and JSON formats
Text Diff
Inline character-level diff between two short texts
XPath Tester
Test XPath expressions against XML and HTML with live results
CSS Selector ↔ XPath Converter
Convert between CSS selectors and XPath expressions for the common patterns both languages share
JSON Diff Checker
Compare two JSON objects and see exactly what changed, path by path
JSON Patch (RFC 6902) Generator & Applier
Diff two JSON documents into an applyable patch, or apply an existing patch to a document
IBAN Validator & Generator
Validate an IBAN's MOD-97 checksum, or generate a test IBAN for any supported country
Credit Card Test Number Generator
Generate Luhn-valid fake card numbers for testing payment forms, or validate a Luhn checksum
Unified Diff / Patch Generator
Generate a real, downloadable .patch file from two texts — usable with git apply or patch
UUID Parser
Decode any UUID or ULID into its version, variant, and embedded timestamp
TypeScript 7 Migration Checker
Paste a tsconfig.json and see exactly which compiler options TypeScript 7 removes
Node.js Type-Stripping Checker
Scan a TypeScript file for syntax Node's built-in type stripping can't run directly
HTTP Header Inspector
Paste raw response headers and get a plain-English explanation of every one
CORS Error Debugger
Walk through exactly why a cross-origin request would be blocked — or confirm it wouldn't be
JSONPath Tester
Test JSONPath expressions against JSON with live results and the exact path to each match
User-Agent String Parser
Break a User-Agent header into browser, engine, OS, and device — with bot detection
CSS & Design Tools
About design tools →CSS Animations
Copy-paste HTML+CSS animation combos with live previews
CSS Flexbox Generator
Build flex container and item properties visually, with a live preview and copy-ready CSS
CSS Grid Generator
Build a CSS grid layout visually — columns, rows, gaps, and per-cell spans
CSS clamp() / Fluid Typography Calculator
Build a fluid font-size that scales smoothly between a min and max viewport — no media queries
CSS Unit Converter
Convert between px, rem, em, pt, and % — with a configurable base font size
Aspect Ratio Calculator
Simplify a width/height into a ratio, or solve for a missing dimension given a ratio
SVG Path Visualizer
Paste a path d attribute and see it rendered live, with its bounding box and command breakdown
CSS Custom Properties Auditor
Paste CSS and find every --token, its usage count, duplicates, and unused or undefined variables
CSS Gradient Generator
Build linear, radial, and conic CSS gradients visually
Color Palette Generator
Generate harmonious color palettes from any base color
Mermaid Diagram Editor
Write flowcharts, sequence diagrams, and more as text — rendered live
Image Color Palette Extractor
Upload an image and extract its dominant colors as a usable palette
CSS Box Shadow Generator
Build single or multi-layer CSS box shadows visually, with live preview
CSS Specificity Calculator
Calculate and compare the specificity of CSS selectors
Placeholder Image Generator
Generate placeholder images with custom size, color, and text
CSS Scrollbar Generator
Style scrollbars with scrollbar-color/width, plus a WebKit fallback
CSS Scroll Carousel Generator
Build a zero-JavaScript carousel with dot navigation using ::scroll-marker and scroll-snap
Security Tools
About security tools →AES / RSA Encryption
Encrypt and decrypt text using AES-GCM and RSA-OAEP
CSP Header Builder & Analyzer
Build a Content-Security-Policy header visually, or paste one to check for unsafe directives
JWT Key Pair Generator
Generate RSA and ECDSA key pairs for signing JWTs — PEM and JWK formats
SSH Key Generator
Generate Ed25519 and RSA SSH key pairs in OpenSSH format, entirely in your browser
TOTP / 2FA Code Generator
Generate live TOTP authentication codes from a secret key — test 2FA integrations in your browser
HOTP Generator
Generate RFC 4226 counter-based one-time passwords — TOTP's time-independent sibling
2FA Backup Codes Generator
Generate one-time recovery codes for account 2FA setup, plus their SHA-256 hashes for server-side storage
package.json Script Inspector
See exactly which scripts run automatically on install, and which dependencies aren't pinned
HTTP Security Headers Checker
Paste raw response headers and check them against HSTS, CSP, X-Frame-Options, and more
JWK ↔ PEM Converter
Convert cryptographic keys between JWK and PEM formats
Secret / API Key Scanner
Paste code or a config file and find hardcoded API keys, tokens, and credentials before they reach git
Password Strength Checker
Check how strong a password actually is — entropy, common-password matches, and predictable patterns
JWK Thumbprint Calculator
Compute an RFC 7638 thumbprint for a JSON Web Key — the canonical fingerprint used as a stable kid
Passkey / WebAuthn Playground
Create a real passkey and run an authentication ceremony entirely in your browser — no server required
Bcrypt Hash Generator & Verifier
Hash a password with bcrypt, or verify a password against an existing hash — entirely in your browser
X.509 / PEM Certificate Decoder
Paste a PEM certificate or chain to see subject, issuer, expiry, SANs, key details, and fingerprints
Accessibility Tools
About accessibility tools →Developer References
About reference tools →HTTP Status Codes
Searchable reference for all HTTP status codes
Chmod Calculator
Calculate Unix file permissions with visual checkboxes
AI Token Counter & Cost Estimator
Estimate how many tokens your prompt costs, and what it'd run across Claude, GPT, and Gemini
Unicode Explorer
Search and inspect Unicode characters by name, code point, or symbol