Testing an authenticated endpoint should not require standing up an identity provider.
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Developer tools
JWT Generator
Secret (HS256 — test only)
Expires in (optional)
Payload
Free · API · MCPToolYour platform
Use JWT Generator three ways
The free JWT Generator on this page works in your browser. The same workflow is available via REST API for apps and via MCP for Cursor, Claude, and other agents — one API key, one plan, one quota. This tool is part of the developer-apis module under Developer Tools.
- Free in browserUse JWT Generator here — no account required.
- REST APICall from your server with
X-Api-Key. - MCP for agentsConnect Cursor or Claude to ToolYour MCP with the same key.
- 1. Get an API keySign in and open Dashboard → API Keys (works for REST and MCP).
- 2. Call or connectUse the REST API from your server, or paste the MCP URL into your agent config.
- 3. Same qualityOutput matches the free web tool across all three surfaces.
What is JWT Generator?
Testing an authenticated endpoint should not require standing up an identity provider. This JWT generator signs a JSON payload with HS256 and a secret you supply, optionally applying an expiry as a number of seconds or a duration string such as 1h or 7d, and returns a token you can paste straight into an Authorization header.
Read this part carefully: use disposable test secrets only. A signing secret pasted into any web form should be treated as compromised, and if the secret is real, every token ever issued with it is forgeable. Rotate immediately if that happens. The tool is HS256 only — asymmetric RS256 and ES256 signing needs your own key material and auth library. To inspect a token's claims without verifying it, use JWT Decoder under Security Tools; to check a signature, use JWT Signature Verifier there. For the header side of the same request, API Request Builder assembles the cURL snippet.
Browser use is free and needs no signup. The same job runs over REST at POST https://api.toolyour.com/api/v1/developer-apis/jwt-generator and over MCP at https://api.toolyour.com/mcp — one API key, one shared monthly credit pool, 1 credit per successful call.
What are common questions about JWT Generator?
Which algorithms are supported?
HS256 only. Asymmetric algorithms such as RS256 and ES256 require private key material that should never leave your environment.
How do I set an expiry?
Pass a number of seconds or a duration string like 15m, 1h, or 7d. Omit it and the token carries no exp claim.
Is it safe to paste my signing secret?
Only a disposable test secret. Anything used in a real environment must be treated as compromised and rotated if it is pasted anywhere public.
Where do I decode or verify a token?
JWT Decoder under Security Tools reads claims without verifying, and JWT Signature Verifier there checks the signature against a secret or public key.
What are the key features of JWT Generator?
HS256 signing from JSON
Supply the claims as a JSON object and a secret; get a signed compact token back.
Flexible expiry
Numeric seconds or human duration strings both set the exp claim correctly.
Explicit safety warning
Every response repeats the test-tokens-only guidance so it travels with the output into scripts and agents.
How do you use JWT Generator?
Write the claims
A JSON object with the subject, roles, or tenant your endpoint expects.
Use a disposable secret
Generate a throwaway value rather than reusing anything from a real environment.
Send and verify
Paste the token into your local request, then confirm behaviour on expiry.
Test tokens the right way
A few habits keep local JWT testing from turning into an incident. Separate secrets per environment — a local test secret must never match staging or production, so a leaked test token proves nothing and unlocks nothing. Short expiries — minutes rather than days, which also gives you a cheap way to test the expired-token path deliberately. Realistic claims — include the issuer, audience, and subject your middleware actually reads, because a token that passes signature checking and then fails on a missing audience wastes debugging time.
Also test the negative cases. A tampered payload, an expired token, and a token signed with the wrong secret should each produce a distinct, correct rejection from your API.
The token lifecycle across ToolYour
Three tools cover the full loop and they live in two categories. Mint here with HS256. Inspect claims with JWT Decoder under Security Tools, which is decode-only and never implies the token is trustworthy. Verify the signature with JWT Signature Verifier there, which is the step that actually establishes authenticity.
For the request itself, API Request Builder turns the token into a complete cURL or fetch snippet, and HTTP Headers Checker shows what the endpoint returns when authentication fails.
Which HTTP / auth helper tools sit in this cluster?
Where do you browse more developer tools tools?
- Developer Tools tools
Browse the full Developer Tools category on ToolYour.
- Marketing Tools tools
Build UTM links, check ads copy limits, QA email subjects, and calculate ROAS/CPC/CTR — free in the browser; R
- Security Tools tools
Check HTTP security headers, TLS, cookies, JWTs, passwords, hashes, and SPF/DKIM/DMARC — free in the browser;
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