33 tools · runs locally · no sign-up
Developer tools. No fuss.
Format JSON, compare text, test regex, decode JWTs, convert timestamps and more. Paste your input and copy the result. Everything runs in your browser, so your data stays on your device.
Popular tools
- JSON FormatterPretty-print or minify JSON with clear error locations.
- Text Diff CheckerCompare two texts side by side or inline.
- Regex TesterTest JavaScript regular expressions with live highlighting.
- JWT DecoderInspect a JSON Web Token's header, payload and expiry.
- Base64 Encoder / DecoderEncode and decode Base64 with full UTF-8 support.
- Unix Timestamp ConverterConvert epoch seconds or milliseconds to dates and back.
- UUID GeneratorGenerate random v4 (and time-ordered v7) UUIDs.
- SQL FormatterFormat SQL for MySQL, PostgreSQL, SQLite and more.
All tools
33 tools shown
Code & Data
- JSON FormatterPretty-print or minify JSON with clear error locations.
- JSON ValidatorCheck JSON syntax and see exactly where it breaks.
- JSON MinifierStrip whitespace from JSON and see the size saved.
- XML FormatterValidate, pretty-print and minify XML documents.
- HTML FormatterBeautify or minify HTML markup.
- CSS FormatterBeautify or minify CSS stylesheets.
- SQL FormatterFormat SQL for MySQL, PostgreSQL, SQLite and more.
- YAML FormatterValidate YAML and convert between YAML and JSON.
- CSV to JSONConvert CSV rows into a JSON array.
- JSON to CSVTurn a JSON array of objects into a CSV file.
Text Tools
- Text Diff CheckerCompare two texts side by side or inline.
- Word CounterCount words, sentences, paragraphs and reading time.
- Character CounterCount characters, code points and UTF-8 bytes.
- Remove Duplicate LinesDelete repeated lines while keeping the original order.
- Sort LinesSort lines alphabetically, numerically or in reverse.
- Find & ReplaceReplace text with plain matching or regular expressions.
- Case ConverterConvert to camelCase, snake_case, Title Case and more.
- Whitespace CleanerTrim lines, collapse spaces and normalise line endings.
Encoding & Security
- Base64 Encoder / DecoderEncode and decode Base64 with full UTF-8 support.
- URL Encoder / DecoderPercent-encode and decode URLs and query values.
- HTML Entities Encoder / DecoderEscape and unescape HTML special characters.
- JWT DecoderInspect a JSON Web Token's header, payload and expiry.
- UUID GeneratorGenerate random v4 (and time-ordered v7) UUIDs.
- Hash GeneratorSHA-256, SHA-384 and SHA-512 hashes of text or files.
- Random String GeneratorCreate secure random strings from chosen characters.
- Password GeneratorGenerate strong passwords with your browser's secure RNG.
- Regex TesterTest JavaScript regular expressions with live highlighting.
Date & Conversion
- Unix Timestamp ConverterConvert epoch seconds or milliseconds to dates and back.
- Date FormatterShow a date in ISO 8601, RFC 2822, locale and custom formats.
- Time Zone ConverterConvert a date and time between IANA time zones.
- Number Base ConverterConvert integers between bases 2, 8, 10, 16 and any up to 36.
- Binary / Hex / Decimal ConverterTwo's complement, bit widths and signed/unsigned views.
- Byte Size ConverterConvert between bytes, KB, MB, GB, KiB, MiB, GiB and more.
Your data stays in your browser
DevKOM is a static site with no backend. The code that formats your JSON or decodes your token is downloaded once and runs in your tab, so the data you paste is never uploaded, logged or stored.
Nothing uploaded
No server receives your input. A strict security policy blocks connections to other sites.
Results as you type
Nothing waits on a server, so results update as you type, even for multi-megabyte inputs.
No account
There is nothing to sign up for and no usage limit. Favorites are saved in your browser only.
Works everywhere
Works on desktop and phone, in light or dark mode, and from the keyboard. Press Ctrl+K to search.
Frequently asked questions
Is DevKOM really free?
Yes. Every tool is free to use with no sign-up, no subscription, no usage limits and no watermarks.
Is my data uploaded anywhere?
No. DevKOM is a static website: all processing happens in JavaScript in your browser tab. There is no backend that could receive what you paste, and the site's security policy blocks the page from connecting to any other server.
Do the tools work offline?
Once a tool page has loaded, it keeps working without a connection, because nothing is sent to a server. Opening a tool you haven't visited yet needs the network to download it.
What does DevKOM store in my browser?
Only your theme choice, your favorite tools and the list of tools you used recently, saved in localStorage. Nothing you type into a tool, such as JSON, tokens or passwords, is ever saved.
Which browsers are supported?
Current versions of Chrome, Edge, Firefox and Safari on desktop and mobile. A few features use newer APIs: word counting uses Intl.Segmenter and hashing uses the Web Crypto API, which needs an https connection.
Can I use DevKOM for production secrets?
The tools are designed for that, since nothing leaves your device, but treat live tokens and passwords with care anywhere. Prefer test data where you can, and close the tab when you're done.