The Developer's Browser Toolbox: JSON, JWT, Hashes and Regex

The slowest part of development isn't writing code — it's the little chores: eyeballing a one-line JSON response, checking what a token contains, verifying a downloaded file. Those chores deserve tools that run offline and never exfiltrate data.

Understand the API: JSON Formatting and Validation

Paste a response and get pretty-printed, highlighted structure; a missing comma reports with an exact line number. The minify mode reverses it for compact transport.

Auth and Integrity: JWT Decoding and Hashing

• JWT decode: paste the token to split out Header and Payload with expiry times converted to readable dates — step one of every 'why 401' hunt.
• Hash calculation: compute SHA-1/256/512 locally. Comparing a downloaded installer against the official digest takes seconds.
• Caveat: decoding a JWT opens the envelope but doesn't verify the signature — that requires your backend and the secret key.

Text and Patterns: Base64 and Live Regex

Base64 handles Chinese without corruption. A regex tester highlights matches as you type — rule writing becomes what-you-see-is-what-you-get instead of edit-run-repeat. URL parsing splits a long link into protocol, host, path and params, perfect for debugging callbacks.

FAQ

Is pasting production data safe?

On this site yes — everything runs locally and uploads nothing. Still, the habit matters more: production secrets and user data never belong in any random web tool.

Can a hash be reversed?

No — SHA-256 is a one-way function. 'Cracking' means precomputing hashes of common strings (rainbow tables), which is exactly why passwords must be salted.