Free Online Developer Tools
Handy utilities for everyday development: format JSON, convert CSV, encode Base64, decode JWTs, test regular expressions and generate hashes.
Free online developer tools that run in your browser: JSON formatter and validator, JSON to CSV and CSV to JSON converters, Base64 and URL encoders, UUID and hash generators, JWT decoder, regex tester and Markdown previewer.
JSON Formatter & Validator
Free JSON formatter and validator. Beautify, minify and validate JSON with clear error messages showing the line and column. Private, runs in your browser.
JSON to CSV Converter
Free JSON to CSV converter. Convert a JSON array of objects into CSV for Excel or Google Sheets, with nested keys flattened. Download in one click.
CSV to JSON Converter
Free CSV to JSON converter. Turn CSV or spreadsheet data into a JSON array with header detection, custom delimiters and number conversion.
Base64 Encoder & Decoder
Free Base64 encoder and decoder. Convert text to Base64 and back with full Unicode support and an optional URL-safe format. Runs in your browser.
URL Encoder & Decoder
Free URL encoder and decoder. Percent-encode or decode text for query strings and links with component and full-URL modes.
UUID Generator
Free UUID generator. Create one or many random version 4 UUIDs (GUIDs) with uppercase and no-hyphen options. Copy all in one click.
Hash Generator (MD5, SHA-256)
Free online hash generator. Create MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes of any text instantly in your browser.
JWT Decoder
Free JWT decoder. Paste a JSON Web Token to read its header and payload, with expiry and issued-at times converted to readable dates.
Regex Tester
Free regex tester. Test JavaScript regular expressions with live match highlighting, capture groups, flags and a replace preview.
Unix Timestamp Converter
Free Unix timestamp converter. Convert epoch seconds or milliseconds to a readable date and convert a date to a timestamp. Shows UTC, local time and ISO.
Markdown Previewer
Free Markdown previewer. Write Markdown on the left and see the formatted result live on the right. Supports tables, lists, links and code blocks.
Developer Tools — frequently asked questions
Is it safe to paste API data or tokens here?
The tools process data locally in your browser and do not upload it. Still, avoid pasting production secrets into any online tool as a general habit.
Do the tools work offline?
Once the page has loaded, most tools keep working without a connection because they run in your browser.
Have an idea? Let’s build it.
Tell us what you need — we’ll reply with a clear, written quote. No pressure, no jargon.