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Free developer tools: format, convert, encode and generate
29 developer tools that work in your browser. Tokens, API payloads and logs are processed on your device, so nothing gets uploaded.
- No upload
- No tracking
- No sign-up
JSON tools 9 tools
- JSON formatterPopularFormat, validate and explore JSON of any size.
- JSON validatorCheck JSON for syntax errors and duplicate keys.
- JSON tree viewerBrowse nested JSON as a tree, search it, and copy the path of any value.
- JSON compareSee every change with its exact path.
- JSON minifySqueeze JSON onto one line and see the bytes saved.
- JSONPath queryType a JSONPath query and see the matching values as you type.
- JSON to YAMLTurn JSON into readable YAML for config files.
- JSON to CSVTurn a JSON array into a spreadsheet-ready CSV.
- JSON to TypeScriptPaste a sample API response and get TypeScript interfaces.
YAML and CSV to JSON 2 tools
Encode and decode 3 tools
Identifiers and hashes 2 tools
Markup, SQL and patterns 5 tools
- Markdown to HTMLWrite Markdown, see the preview, copy the HTML.
- HTML to MarkdownPaste HTML, get tidy Markdown.
- SQL formatterPaste a messy query, get readable SQL.
- Regex testerPopularType a pattern and see every match and group highlighted.
- Cron expression explainerPaste a 5-field cron expression to read it in plain English and preview the next five runs.
Converters and generators 5 tools
- Password generatorCreate strong passwords and passphrases with your browser’s secure random generator.
- Unix timestamp converterPaste an epoch time or a date.
- Color converterType a colour in any format to get the others, plus WCAG AA and AAA contrast marks.
- Color palette generatorPick a base colour to get shades, tints, colour-wheel schemes and a 50 to 900 scale.
- Number base converterConvert between binary, octal, decimal and hex.
QR codes and barcodes 3 tools
No tool matches that search.
Which Developer tool do I need?
Find the right tool by what you’re trying to do.
| I want to… | Use |
|---|---|
| Pretty-print or check JSON | JSON formatter or JSON validator |
| Turn JSON into a spreadsheet | JSON to CSV |
| Read what is inside a JWT | JWT decoder |
| Make unique IDs | UUID generator |
| Test a regular expression | Regex tester |
| Create a strong password | Password generator |
| Make a QR code | QR code generator |
Developer questions
Privacy, limits and file sizes.
Is it safe to paste tokens and API data?
Yes. Everything runs in your browser. Text is never sent to a server and is not saved in the page address.
Does the JWT decoder verify signatures?
No. It only decodes the token so you can read it. Verify signatures in your own code.
Are the generated passwords and IDs random?
Yes. They use your browser’s secure random number generator.
Does it work with large files?
Text over 1 MB is processed in a background worker so the page stays responsive.