CapyToolkit

CapyToolkit is a growing collection of free, privacy-first browser tools, and developers are one of its core audiences. Its 50+ tools cover the jobs that interrupt development: decoding a JWT before it expires, reformatting a messy API response, testing one regex against five edge cases, or checking what a cron expression schedules. The browser does all the work.

The developer stack covers JSON formatting and tree browsing, a live regex tester, JWT claims inspection, cron parsing, Base64 text and file conversion, hashing across MD5, SHA-1, SHA-256, and SHA-512, and UUID v1, v4, and v7. A SQL workbench queries local Parquet, CSV, and JSON files, and a log explorer filters files past 500 MB.

Security tools (PII scrubber, EXIF scrubber, X.509 certificate inspector) and personal tools (PDFs, passport photos, receipts) follow the same rules: nothing is uploaded, stored, or gated behind an account. Always free.