Developer Tools
Twenty free developer tools that run entirely in your browser: encoders, decoders, formatters, generators, converters and testers. No sign-up, no uploads, nothing leaves your device. Pick a tool below.
- Base64 Encoder and DecoderEncode text to Base64 or decode it back, with full Unicode support.
- URL Encoder and DecoderPercent-encode URLs or decode them back to readable text.
- JWT DecoderDecode JWT header and payload, with expiry in plain dates.
- Unix Timestamp ConverterConvert Unix timestamps to dates and back, with auto unit detection.
- UUID GeneratorGenerate random version 4 UUIDs, single or bulk.
- Regex TesterTest regex patterns live with highlighting and capture groups.
- Hash GeneratorCompute MD5, SHA-1 and SHA-2 hashes of any text.
- Lorem Ipsum GeneratorGenerate lorem ipsum placeholder text for mockups.
- Markdown PreviewLive markdown editor with instant HTML preview.
- HTML Entity Encoder / DecoderEncode text to HTML entities and decode them back.
- CSS MinifierCompress CSS by removing comments and whitespace.
- JavaScript MinifierCompress JavaScript by stripping comments and whitespace.
- SQL FormatterFormat messy SQL into clean, readable queries.
- XML Formatter & ValidatorPretty-print, minify and validate XML documents.
- JSON to YAML ConverterConvert JSON documents into clean YAML.
- Cron Expression ExplainerTranslate cron expressions into plain-English schedules.
- Diff CheckerCompare two texts line by line with highlighted changes.
- Slug GeneratorTurn headlines into clean, SEO-friendly URL slugs.
- Chmod CalculatorCompute Unix file permissions: octal, symbolic and chmod command.
- Number Base ConverterConvert numbers between binary, octal, decimal and hex.
More developer tools
- JSON Formatter and ValidatorFormat, minify, and validate JSON right in your browser.
- QR Code GeneratorMake QR codes for URLs, text, and contact info. Custom colors, PNG download.
- Password GeneratorCrypto-random passwords with a strength meter.
- Character CounterCharacters, bytes, X remaining and SMS segments live.
- Case ConverterUPPER, lower, Title, Sentence, camel, snake and kebab case.
- Color ToolsPicker, HEX/RGB/HSL converter, palettes and contrast checker.
Frequently asked questions
Are these developer tools free?
Yes. Every tool on this page is free forever, with no account, no limits and no watermarks. They are funded the same way as the rest of Toolantern.
Do I need to install anything?
No. Each tool runs in any modern browser, on desktop or mobile. Once the page loads, most tools keep working even if your connection drops.
Is my code or data sent to a server?
No. All processing happens locally in your browser with JavaScript, so tokens, keys and proprietary code never leave your device. That is also why the JWT decoder warns you never to paste signing secrets: a decoder only needs the token, not the secret.
Which tools do developers use most?
The JSON formatter, Base64 encoder, JWT decoder, regex tester and hash generator are the classics. For scheduling, the cron explainer and Unix timestamp converter save the most head-scratching.