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DEV · TOOL COLLECTION

Free Developer Tools

Inspect JSON, encodings, hashes, regex, Cron, JWT, timestamps and Unix permissions.

10 FREE TOOLS

Choose the tool
that fits the task.

01{ }JSON Formatter & ValidatorClean up complex JSON and catch syntax errors quickly.Developer↗02↔JSON ↔ CSV ConverterMove copied data between JSON and CSV instantly.Developer↗0364URL & Base64 EncoderHandle common developer encodings in one place.Developer↗04#Hash GeneratorCreate integrity hashes locally with Web Crypto.Developer↗05.*Regex TesterSafely try a regular expression on your own sample.Developer↗06*/Cron Expression Builder & ExplainerBuild a recurring schedule from presets or inspect a custom expression before deployment.Developer↗07UTCUnix Timestamp ConverterAuto-detect seconds or milliseconds and view local, UTC and ISO values together.Developer↗08JWTJWT DecoderQuickly inspect JWT claims while keeping the distinction between decoding and signature verification clear.Developer↗09±Text Diff CheckerFind changed lines in configs, drafts and code snippets directly in your browser.Developer↗10755chmod CalculatorUse checkboxes or a three-digit octal value to build a Unix permission and chmod command.Developer↗

CATEGORY GUIDE · 2026-07-23

Free Developer Tools guide

Development often requires checking one small string or configuration without opening a heavy application. This collection handles validation, conversion and previews in one browser screen.

JWT decoding does not verify a signature, and Cron previews use the browser's local time zone. Compare results with the actual server and library before production use.

Before you start

  • Do not paste sensitive production tokens on a shared device.
  • A general hash does not replace password hashing or a digital signature.
  • Verify server time zone and combined Cron day-field behavior.

Frequently asked questions

Is development data transmitted?

Most inputs are processed only in the current browser.

Can I use a result directly in production?

Test it against the target environment and its official documentation first.