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A STARTING POINT, MADE FOR YOU

The certificates and http desk
toolbox.

Read a TLS certificate, look up an HTTP status code and inspect tokens, URLs and hashes.

INSIDE THE TOOLBOX

11 useful places to start.

Starter collection

Reading a certificate does not verify its signature, its chain or its revocation status, and says nothing about whether it is trusted. Everything runs in your browser.

X.509 certificate parser and decoder

Read a PEM or DER certificate on your device: subject, issuer, validity, key, extensions, fingerprints and plain factual flags. It does not check trust.

HTTP status code reference

Search every HTTP status code in the IANA registry by number, class or words: meaning, cacheability, retry advice, key headers and the RFC section.

JWT decoder

Inspect a JSON Web Token’s header and payload locally.

JWT signature verifier (HS256, RS256, ES256)

Check a JWT’s signature with an HMAC secret, JWK or PEM public key, and its exp and nbf claims at a time you choose, on your device.

URL parser

Break a URL into its scheme, host, port, path, query parameters and fragment.

robots.txt tester

Check which URLs a robots.txt allows or blocks for a crawler, with the exact rule that decided each one, following RFC 9309.

Punycode and IDN domain converter

Convert international domain names to xn-- Punycode and back, compare with the browser’s own conversion and flag lookalike letters.

SHA hash generator

Create SHA-256, SHA-384 or SHA-512 hashes of text.

HMAC generator

Compute an HMAC-SHA-256, SHA-1, SHA-384 or SHA-512 message authentication code with a secret key, on your device.

UUID and ULID inspector

Decode a UUID of any version or a ULID: version, variant, embedded timestamp in UTC, clock sequence, node and every common spelling.

Cron expression explainer

Read a five-field cron schedule in plain terms and list its next run times.

SMALL TASKS. LESS FRICTION.

A few things you
can tick off.