ES256
What this is
ES256 uses ECDSA on the P-256 curve with SHA-256. Signatures are ~64 bytes. Apple Sign In and many modern issuers prefer it. JWT ECDSA signatures are raw R||S (IEEE P1363), which Web Crypto verifies natively. Mobile, cookies, high-QPS gateways where RSA verify CPU or size hurts.
Open the decoder and paste a ES256 token. Verification stays in the browser.
FAQ
- DER vs raw signatures?
- JOSE is raw concatenated R and S, not ASN.1 DER. A library that emits DER will fail verification here and in most JWT stacks.