FREE TOOLS
JWS Signature Verifier
Verify a supported compact JWS signature against supplied public-key material.
Compact JWS, Expected algorithm, Public key format, Public key, Optional public source file (takes precedence)
JSON
Browser only
Runs locally in your browser. Your files, pasted content and generated output are not uploaded. Reset clears this tool’s working data.
This tool needs JavaScript. If it does not load, refresh the page and try again.
How to use this tool
- Enter the displayed example values,or choose the local input files requested by the controls. Optional source files take precedence where labelled.
- Choose Verify signature and inspect the complete result and any reported limitations.
- Use Download result and each companion download link to save complete outputs. Reset clears output and restores example controls.
Examples
Compact JWS: eyAidHlwIjoiSk9TRSIsICJhbGciOiJFZERTQSIsICJraWQiOiJleGFtcGxlIiB9.eyJtZXNzYWdlIjoiRFRIIGxvY2FsIHNpZ25hdHVyZSBleGFtcGxlIiwidW5pY29kZSI6ImNhZsOpIPCfmIAifQ.x-ZRp0fGFmyI7-iNNTHXR16Sah4x57IcP93BgyO2xs0t9qPUCF7B9Hdy3TvgIpzokFHu5ahNo0k87JeghHeZDA
Expected algorithm: EdDSA
Public key format: jwk
Public key: {
"kty": "OKP",
"crv": "Ed25519",
"x": "oReoyKPYiOaV3lPiGqvYuDi_UGvwcHCKoeroLrEZt9Y"
}
Limitations
- Verify one compact JWS against your supplied public JWK or SPKI key and an explicitly selected algorithm:RS256/384/512,PS256/384/512,ES256/384/512 or EdDSA with Ed25519. Verify the original encoded header.payload bytes;show complete decoded payload bytes and the true/false signature result. RSA2048–8192 bits and algorithm-matched curves only. PSS salt equals hash length;ECDSA uses JOSE fixed-width R||S. No HMAC,none,crit/b64 extensions,JWE or detached external payload. An empty middle segment is an attached empty payload. Header key URLs/declarations are ignored;no requests occur. A valid signature does not validate JWT claims,certificate chains,key identity or authorization. Up to100,000 characters per pasted field,128 KiB per optional file,400,000 combined input bytes and4 MiB output. ASN.1 trees are bounded to20,000 nodes/40 levels. All processing stays in your browser.
- Complete outputs only. Unsupported or oversized input is refused. Follow the displayed job-specific bounds and format policies.