Developer Tools

Fast, free, no-signup developer utilities — JSON, Base64, JWT, UUID, timestamps and hashing. Everything runs in your browser; your data never leaves your device.

JSON & Data JSON Formatter & Validator Pretty-print, minify and validate JSON instantly. Runs entirely in your browser — your data never leaves your device. JSON & Data JSON Diff & Compare Compare two JSON objects and see what changed — added, removed and modified keys by path. Runs entirely in your browser. JSON & Data JSON to CSV Converter Turn a JSON array of objects into clean CSV — pick the delimiter and download. Runs entirely in your browser. JSON & Data CSV to JSON Converter Turn CSV into a clean JSON array of objects — pick the delimiter and infer types. Runs entirely in your browser. API & SQL cURL to Code Converter Paste a cURL command and get equivalent JavaScript fetch, Python requests or Node code. Runs entirely in your browser. API & SQL JSON to SQL Converter Turn a JSON array of objects into SQL INSERT statements, with optional CREATE TABLE. Runs entirely in your browser. API & SQL SQL Formatter & Beautifier Beautify messy SQL into clean, readable queries — keywords uppercased and clauses on their own lines. Runs entirely in your browser. Encoding Base64 Encode & Decode Convert text and files to and from Base64. Runs entirely in your browser — nothing is uploaded. Encoding URL Encoder & Decoder Percent-encode text for URLs or decode it back. Runs entirely in your browser. Encoding HTML Entity Encoder & Decoder Escape text to HTML entities or decode them back. Runs entirely in your browser. Encoding Number Base Converter Convert a number between binary, octal, decimal, hex and any base (2–36). Runs entirely in your browser. Text Regex Tester Test a regular expression against your text with live highlighting, match counts and capture groups. Runs entirely in your browser. Text Case Converter Convert text between camelCase, snake_case, kebab-case, Title Case and more — all at once. Runs entirely in your browser. Text Text Diff & Compare Compare two texts line by line and see what changed — added and removed lines, colour-coded. Runs entirely in your browser. Text Word & Character Counter Count words, characters, sentences, paragraphs and reading time live as you type. Runs entirely in your browser. Text Markdown to HTML Write Markdown and see a live HTML preview, then copy the HTML. Runs entirely in your browser. Text Sort & Dedupe Text Lines Sort, deduplicate, reverse, shuffle and clean a list of lines. Runs entirely in your browser. CSS & Design Color Converter & Picker Pick a color and convert between HEX, RGB and HSL instantly, with a live swatch. Runs entirely in your browser. CSS & Design CSS Gradient Generator Build linear and radial CSS gradients with a live preview and copy the code. Runs entirely in your browser. CSS & Design CSS Box Shadow Generator Design a box-shadow visually and copy the CSS — offset, blur, spread, color and inset, with a live preview. CSS & Design Color Palette Generator Generate tints, shades and harmonious schemes from a base colour, and copy any hex. Runs entirely in your browser. Security JWT Decoder Paste a JSON Web Token to read its header and claims. Decoded entirely in your browser — your token is never sent anywhere. Security Hash Generator Get MD5, SHA-1, SHA-256 and SHA-512 hashes of your text as you type. Computed in your browser — nothing is uploaded. Security JWT Generator Create and sign a JWT with HS256 and your secret. Signed in your browser with the Web Crypto API — your secret never leaves your device. Security JWT Validator Verify a JWT’s HS256 signature with your secret and check its expiry. Verified in your browser — nothing is uploaded. Generators UUID Generator Generate cryptographically-random version 4 UUIDs in bulk. Created in your browser with the Web Crypto API. Generators Strong Password Generator Generate strong, random passwords with the length and characters you choose. Created in your browser with the Web Crypto API — never sent anywhere. Generators Lorem Ipsum Generator Generate placeholder text by paragraphs, sentences or words and copy it. Runs entirely in your browser. Date & Time Unix Timestamp Converter Convert Unix/epoch time to a human date and back, in any timezone. Runs entirely in your browser. Date & Time Cron Expression Generator & Reader Type a cron expression to see it explained in plain English and its next run times — or start from a preset. Runs entirely in your browser. Testing Playwright Test Generator Add steps — visit, click, fill, assert — and get a ready-to-run Playwright test. Generated entirely in your browser. Testing Cypress Test Generator Add steps — visit, click, type, assert — and get a ready-to-run Cypress test. Generated entirely in your browser. Testing Selenium Script Generator Add steps — open, click, send keys, assert — and get a ready-to-run Selenium (Python) script. Generated entirely in your browser.

Frequently Asked Questions

Are these developer tools free?

Yes — every tool is completely free with no signup, no limits and no watermarks.

Is my data sent to a server?

No. Each tool runs entirely in your browser, so the data you paste — JSON, tokens, text — never leaves your device.

Do they work offline and on mobile?

They are lightweight and work on phones and desktops; once the page has loaded most tools keep working without a connection.

A growing toolbox for developers and QA engineers: format and validate JSON, encode and decode Base64, decode JWTs, generate UUIDs, convert Unix timestamps and hash text with MD5 and SHA. Each tool is client-side, so it is fast and private — nothing you paste is uploaded or stored. More tools are added regularly.