MongoDB ObjectId Generator
Generate and decode MongoDB ObjectIds, including their embedded timestamp.
JWT Generator
Build and sign a JWT with HS256, HS384 or HS512 for testing.
Use a throwaway secret for test tokens. A secret typed into any web page should be treated as exposed.
Quick Tool Overview
The JWT Generator builds a token from standard and custom claims and signs it with HS256, HS384 or HS512, with helpers for iat and exp so you are not doing epoch arithmetic by hand.
- What it does
- Builds and signs a JWT
- You give it
- Claims, an algorithm and a secret
- You get back
- A signed, ready-to-use token
- Best for
- Testing APIs, middleware and auth flows
About the JWT Generator
Testing anything that consumes JWTs means having a supply of them, with the claims you need and an expiry that has not passed. This builds one: set the payload, choose an algorithm, provide the secret, and get a signed token.
The registered claims have helpers because they are the fiddly part. iat is filled with the current time, exp is set by picking a duration rather than doing epoch arithmetic, and sub, iss and aud have their own fields alongside whatever custom claims you add. Signing uses HMAC — HS256, HS384 or HS512 — which is what a symmetric secret supports; RS256 needs a private key and is deliberately out of scope for a browser tool.
Key features of the JWT Generator
Expiry without arithmetic
Pick a duration and exp is calculated for you, with iat filled from the current time.
Standard and custom claims
Dedicated fields for sub, iss and aud, plus a JSON box for anything else the token needs to carry.
Verified as it is built
The generated token is decoded back and shown, so you can confirm the claims came out the way you intended.
Real HMAC signing
Signatures come from the browser’s own crypto, so the tokens verify correctly in any library.
Honest about scope
RS256 needs a private key, and the page declines to accept one rather than encouraging the habit.
How to use the JWT Generator
-
1
Set the claims
Fill the standard fields and add any custom claims as JSON.
-
2
Choose an expiry
Pick a duration and exp is calculated for you.
-
3
Enter the secret
The shared signing key. Use a throwaway one for test tokens.
-
4
Copy the token
The signed JWT is ready to paste into an Authorization header.
Frequently asked questions
HS256 unless something requires otherwise. The larger HMAC variants are rarely needed, and the real security comes from the secret being long and random rather than from the digest size.
At least as long as the digest — 32 bytes for HS256. A short or guessable secret makes the signature worthless, because an attacker can simply brute-force it offline against any token they hold.
No. That needs an RSA private key, and pasting one into a web page is a bad habit even when the page is honest about being local. Use your own tooling for asymmetric signing.
The tokens are correctly signed, so they work. But a secret typed into any web tool should be treated as exposed — generate production tokens on your own infrastructure.
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