SolSigs ProofGuard · x402 · Solana Mainnet USDC

Proof receipts for AI agents that pay APIs.

ProofGuard gives autonomous buyers durable evidence after a paid endpoint call: what was promised, what was delivered, and whether there is enough evidence for a refund/dispute workflow.

Call the APIListed on x402scanGitHub docs
$0.003per evaluation
4evidence objects
3verification modes
USDCSolana mainnet
What it returns

A signed evidence bundle, not vague trust language.

Endpoint trust score

Score, decision, and reason codes for a paid endpoint route.

Payment expectation receipt

Records the route, expected amount, method, network, and payment context before fulfillment.

Fulfillment receipt

Records observed delivery, latency, freshness, status, hashes, and contract match signals.

Refund evidence package

Bundles stale, malformed, missing, misleading, or mismatch evidence into a machine-readable package.

Evidence honesty

ProofGuard labels how strong the evidence is.

No fake certainty. Third-party caller-supplied observations are clearly marked as self-attested. Stronger claims are reserved for SolSigs-instrumented or ProofGuard-probed evidence.

solsigs_instrumentedproofguard_probedself_attested

Endpoint

POST /proofguard/evaluate

curl -X POST https://solsigs.com/proofguard/evaluate \ -H "content-type: application/json" \ -H "payment-signature: <solana-usdc-x402-signature>" \ -d '{"endpoint":"https://solsigs.com","route":"/dex","method":"POST"}'
Example response shape
{ "ok": true, "product": "SolSigs ProofGuard", "verification_mode": "solsigs_instrumented", "claim_boundary": "Evidence reflects SolSigs-instrumented observations.", "trust_score": { "score": 96, "decision": "ALLOW" }, "expectation_receipt": { "route": "/dex", "amount_atomic": "3000" }, "fulfillment_receipt": { "fulfilled": true, "response_hash": "..." }, "refund_evidence_package": { "refund_requested": false, "evidence": [] } }