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fastapi.online — Decode Signature (Hex)
x402
fastapi.online — Decode Signature (Hex) is a paid API for AI agents from api.fastapi.online, paid per call via x402, $0.0005/call, status unknown (last checked 2026-10-12).
Decodes a hex-encoded cryptographic signature into its constituent components
Price / call$0.0005
Success—
StatusUnknown
How this service works
Chat, embeddings, OCR, speech-to-text, image editing, image understanding (captioning/Q&A), text-to-speech, translation, writing tools, classification tools, developer tools, local utilities, format/checksum validators, encoding & crypto utilities, date/time calculators, geo/coordinate math, math & finance calculators, novelty tools, and business/social writing generators — 179 endpoints in all, across multiple specialized self-hosted models. Pay per call with crypto — no signup — or get an API key.
Output
Returns the decoded contents of the hex-encoded signature, including its parsed cryptographic components such as algorithm identifiers, r and s integer values, or other signature fields depending on the signature scheme encoded in the hex input.
Example use cases
Inspect raw ECDSA signature bytes
“I have a raw hex signature from a blockchain transaction — '3044022019a1b2...cc3344' — can you decode it and tell me what the r and s values are?”
Debug malformed signature data
“I'm getting a signature verification error in my app. Here's the hex-encoded signature I'm working with: '3045022100deadbeef...'. Can you decode it so I can see if the structure looks correct?”
Audit cryptographic signing output
“We need to review the signature our signing service produced. It's hex-encoded as '304502...ff'. Please decode it so our security team can inspect its components.”
Technical details
Endpoint
POSThttps://api.fastapi.online/decode-signature?utm_source=zero.xyzWhen to prefer
Use this endpoint when you have a raw hex-encoded cryptographic signature and need to inspect or extract its inner components without writing custom parsing code. Suitable for quick developer debugging, security audits, or automated pipelines that need to inspect signature structures. Prefer this over manual bit-parsing or writing custom DER/ASN.1 decoders.
Side effects
- Invalid or malformed hex string returns an error
- Non-signature hex data may produce garbled or unexpected output
- Unsupported signature formats may not decode correctly
- Empty or missing 'hex' field causes request validation failure
- Odd-length hex strings are invalid and will likely error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| hex | string |
Tags
x402
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