Free Online Developer Tools
Format JSON, encode Base64, generate hashes, minify assets and convert timestamps — without pasting a production payload into somebody else's server. Every tool here runs in your browser using the platform's own APIs, so a response containing real keys never leaves your machine.
All 10 developer tools
JSON Formatter
Format, validate, and minify JSON. Choose indent size and see syntax errors inline.
JSON ↔ CSV Converter
Convert JSON arrays to CSV or parse CSV back to JSON. Handles quoted fields and special characters.
URL Encoder & Decoder
Encode or decode URL components and full URLs. Supports encodeURIComponent and encodeURI.
Base64 Encoder & Decoder
Encode text to Base64 or decode Base64 strings back to plain text. Supports Unicode.
Timestamp Converter
Convert Unix timestamps to human-readable dates. Supports seconds, milliseconds, and date strings.
Hash Generator
Generate SHA-256, SHA-384, and SHA-512 hashes using Web Crypto API. Output in hex or Base64.
HTML Minifier
Minify HTML by removing comments, collapsing whitespace, and optimizing attributes. See size reduction.
CSS Minifier
Minify CSS by removing comments and collapsing whitespace. See before/after file size comparison.
JavaScript Minifier
Minify JavaScript using Terser. Supports mangling and compression with size reduction stats.
SQL Formatter
Beautify SQL queries with dialect support for MySQL, PostgreSQL, and BigQuery. Control keyword case.
Questions
- Is it safe to paste a production payload?
- Here, yes — parsing and formatting use the browser's own engines and nothing is transmitted. That is not true of most online formatters, where the paste is an HTTP request. Check your network tab if you want to confirm it.
- Which hash should I use?
- SHA-256 for anything current. MD5 and SHA-1 are cryptographically broken and should only ever be used to detect accidental corruption. For passwords, none of these — use bcrypt or Argon2, which are deliberately slow.
- Do these replace my build tools?
- No, and they are not meant to. The minifiers here remove comments and whitespace; a real bundler also renames variables and drops dead code. Use these for a one-off or a quick check, and your build for what you ship.