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Delx Commerce — EVM Signature R/S Shape Check
x402
Delx Commerce — EVM Signature R/S Shape Check is a paid API for AI agents from commerce.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).
Validates whether the r and s components of an EVM ECDSA signature have valid cryptographic shape (within the secp256k1 curve bounds)
Price / call$0.001
Success—
StatusUnknown
How this service works
Pay-per-result APIs for agents. No signup. Exact price. Verifiable delivery. USDC on Base + Solana via x402.
Output
Returns a JSON object containing the original r and s values, a shape_valid boolean indicating whether both components are well-formed secp256k1 scalars, the operation name, status (pass/fail), and an evidence object with the SHA-256 hash of the input, a retained:false flag confirming no data storage, and a count of external calls made (always 0).
Example use cases
Pre-broadcast signature sanity check
“Before I broadcast this Ethereum transaction, can you verify that the signature r value 0x1a2b3c... and s value 0x4d5e6f... are actually valid secp256k1 scalars so we don't waste gas on a malformed signature?”
Agent wallet signing pipeline guard
“My agent just produced a signature with r=0xdeadbeef... and s=0xcafe1234... — can you run a shape check on those to confirm they're within the valid ECDSA range before we proceed?”
Debugging a rejected EVM transaction
“I submitted an Ethereum transaction and it got rejected — can you check whether the r and s components of my signature, 0xaaaa... and 0xbbbb..., have valid curve shape so I can figure out if the signature itself was the problem?”
Technical details
Endpoint
POSThttps://commerce.delx.ai/api/v1/x402/evm-signature-rs-shape-check?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a cheap, stateless, privacy-preserving preflight check on ECDSA signature r/s components before committing to an on-chain operation. Ideal for agent pipelines that need to guard against malformed signatures without storing any data. At $0.001 USDC per call with verifiable non-retention (SHA-256 evidence hash, no external calls), it's well-suited for high-frequency signature validation in automated workflows. Prefer this over full signature recovery endpoints when you only need shape validity, not signer identity.
Side effects
- Malformed hex string for r or s returns a validation error
- Values exceeding secp256k1 curve order return shape_valid: false
- Input exceeding maxLength of 8192 characters rejected
- Missing r or s field returns a schema validation error
- Payment failure via x402 protocol prevents execution
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| r | string | R supplied to EVM Signature Rs Shape Check; used only for this bounded calculation and processed in memory without retention. |
| s | string | S supplied to EVM Signature Rs Shape Check; used only for this bounded calculation and processed in memory without retention. |
Output
Schema · Response
{
"type": "json",
"example": {
"result": {
"r": "0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
"s": "0xbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb",
"shape_valid": true
},
"schema": "delx/util-evm-signature-rs-shape-check/v1",
"status": "pass",
"evidence": {
"retained": false,
"input_sha256": "a8860b963293e5de6a0dcbb51fc93e8b57c3290aa6e7a93a20c01c06569bf179",
"external_calls": 0
},
"operation": "evm_preflight:evm_signature_rs_shape_check"
}
}Tags
x402
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