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Programmer & Developer Tools

Free in-browser developer tools: JSON validator, code beautifier, minifier, JWT debugger, base64 converter, regex tester, diff checker, and cron generator.

  • JSON Validator — Validate, parse, and prettify JSON — load it from a URL or curl command, or convert a Python dict (single quotes, True/False/None) to JSON. Identifies syntax errors with precise line number reporting.
  • Code Beautifier — Automatically format your JavaScript, CSS, and HTML with customizable indentation and style rules.
  • Minifier — Reduce bundle sizes by removing whitespace, comments, and optimizing code structure for production.
  • SQL Formatter & Beautifier — Pretty-print and indent SQL queries across dialects (PostgreSQL, MySQL, T-SQL, BigQuery, and more) with configurable keyword casing.
  • XML Formatter — Beautify and validate XML with configurable indentation, or minify it to the smallest valid output — entirely in your browser.
  • JSON Diff — Compare two JSON objects (or Python dicts) structurally to spot added, removed, and changed keys — or switch to line and word mode for plain text and code.
  • RegEx Tester — Build and test regular expressions in real-time with syntax highlighting and match group visualization.
  • Base64 Converter — Quickly encode and decode strings or files to Base64 format for safe data transmission.
  • URL Encoder / Decoder — Percent-encode or decode text, URLs, and query strings — with batch line mode and a parsed parameter breakdown.
  • JWT Debugger — Decode and inspect JSON Web Tokens. Verify signatures and view payload data without exposing secrets.
  • JWT Generator & Signer — Build and sign JSON Web Tokens (HS256/384/512) from a custom header and payload using your secret — signed locally with the Web Crypto API.
  • Hash Generator (MD5, SHA-256…) — Compute MD5, SHA-1, SHA-256, and SHA-512 hashes of text or files, and verify downloads against an expected checksum — all on your device.
  • Password Generator — Generate strong, random passwords with a strength meter — choose length, character sets, no-look-alikes, or pronounceable mode. Cryptographically secure, never saved.
  • Bcrypt Hash & Verify — Generate bcrypt password hashes with a configurable cost factor, or verify a password against an existing hash — entirely client-side.
  • UUID Generator (v1–v7) & Random String — Bulk-generate UUIDs of every version — random v4, sortable v7/v6, timestamp v1, name-based v3/v5 — plus crypto-random strings with custom characters.
  • QR Code Generator — Turn any text or URL into a QR code — custom colors, error-correction level, and crisp SVG or high-res PNG export. No watermark, no signup.
  • YAML ↔ JSON Converter — Convert between YAML and JSON in both directions with live preview, validation with exact error positions, and multi-document support.
  • JSON ↔ CSV Converter — Flatten JSON arrays into CSV with column selection and Excel-ready download, or parse CSV back to JSON with type inference.
  • TOML ↔ JSON Converter — Convert between TOML and JSON in both directions with live preview and clear error messages — perfect for config files.
  • .env ↔ JSON Converter — Parse .env files to JSON (comments, quotes, multiline values handled) or generate .env from JSON config — entirely in your browser.
  • JSON to TypeScript & Types — Generate TypeScript interfaces, Go structs, Python TypedDicts, or Zod schemas from a JSON sample — nested objects and arrays are inferred automatically.
  • JSONPath Query Tester — Run JSONPath queries against any JSON document live and see the matched results instantly — great for exploring API responses.
  • Mock / Fake Data Generator — Generate realistic fake datasets — names, emails, UUIDs, dates, and more — and export them as JSON, CSV, or SQL inserts for testing and seeding.
  • String Escape / Unescape — Escape and unescape strings for JSON, JavaScript, HTML entities, SQL, and backslash sequences — both directions, live in your browser.
  • Slugify (URL Slug Generator) — Turn any text into clean, URL-safe slugs — strip accents, pick a separator, set a max length — processing each line live in your browser.
  • Number Base Converter — Convert numbers between binary, octal, decimal, and hexadecimal live, with a bitwise calculator (AND, OR, XOR, NOT, shifts) — arbitrary-precision via BigInt.
  • CSS px ↔ rem/em Converter — Convert px to rem and em at a chosen root font size, both directions, with a handy quick-reference table — exact math, in your browser.
  • Color Converter & Contrast Checker — Convert colors between HEX, RGB, HSL, HSV, and OKLCH, and check WCAG AA/AAA contrast between any two colors — all live in your browser.
  • Cron Generator — Generate cron job expressions using a human-friendly interface. Includes execution schedule preview.
  • Cron Expression Explainer — Paste a cron expression to get its plain-English meaning, a per-field breakdown, and the next scheduled run times — all in your browser.
  • cURL → Code Converter — Paste a curl command and get equivalent fetch, axios, or Python requests code — headers, body, method, and basic auth parsed automatically.
  • chmod Permission Calculator — Convert Unix file permissions between a click-grid, octal (e.g. 750), and symbolic (rwxr-x---) — including setuid, setgid, and sticky bits.
  • .gitignore Generator — Compose a .gitignore from language, framework, and OS templates — search, pick, and download a ready-to-use file in seconds.
  • HTTP Status Code Reference — A searchable, filterable reference of every HTTP status code with its meaning and when to use it — from 100 to 511.
  • SVG Optimizer — Minify and clean SVG markup — strip comments, editor metadata, and whitespace, round coordinates — with a live before/after size readout and preview.
  • Open Graph & Social Card Generator — Generate Open Graph and Twitter Card meta tags with a live link-preview for X, Facebook, LinkedIn, and Discord — plus title/description length warnings and an image-size validator.
  • IPv4 Subnet Calculator — Compute network and broadcast addresses, host range, usable hosts, subnet mask, wildcard, and CIDR for any IPv4 address and prefix.
  • Open Graph Image Generator — Design the 1200×630 social share image itself — background, title, description, logo, and accent — then download a PNG. Pairs with the Open Graph meta tag generator.
  • Link in Bio Builder — Build a free Linktree-style link-in-bio page — add your name, bio, avatar, and links, pick a theme, and download a standalone HTML page or share an editable link. No account, no hosting lock-in.
  • HAR Analyzer — Open, explore, and analyze HAR network captures — request waterfall, headers/cookies/payload inspector, performance insights, and a printable report. Parsed entirely in your browser.
  • HAR Compare / Diff — Compare two HAR captures side by side — see added, removed, and changed requests with status, size, and timing deltas. Perfect for before/after performance regressions and A/B captures.
  • HAR to Load Test — Convert a HAR capture into a load-test script — k6, Artillery, JMeter (.jmx), or Locust. Filter requests, include headers, and redact secrets. Generates a script to run yourself; nothing is uploaded.
  • Find & Replace (Regex) — Find and replace text in bulk — plain or regular-expression search with capture groups, case-insensitive, whole-word, and multiline options, plus a live match count and highlighted preview.
  • Strip HTML Tags — Remove HTML tags to get clean plain text — optionally preserve line breaks and keep link URLs. Entities are decoded automatically.
  • Line Tools (Prefix, Suffix, Number) — Bulk-edit lines of text — add a prefix or suffix, number lines, and indent — applied live to every line.
  • Text to Binary / Hex / ASCII — Convert text to and from binary, hexadecimal, decimal, and octal — UTF-8 aware, both directions, with a swap button.
  • Unicode Character Inspector — Inspect any text character by character — code point, category, Unicode block, UTF-8/UTF-16 bytes, and HTML, JS, CSS, and URL escapes.