x402 Verification API

Paid, bounded verification of a candidate result with a signed, content-addressed receipt. USDC on Base; capture follows an approved or rejected verdict. Inconclusive runs are not billed.

Multi-chain OFAC SDN exact-address screening. 960 sanctioned addresses across 19 chains, parsed directly from the US Treasury sdn_advanced.xml, including the Solana entries the Chainalysis on-chain oracle cannot see because it is EVM only. Every response is ECDSA-signed and carries sdn_snapshot_at, so a caller can prove which version of the list was used. The raw source file is hashed every six hours into a public append-only chain anchored to Bitcoin: https://sanctions.nsgoods.org/sdn-log/. Free preview on every endpoint, no account and no API key. Settles in USDC on Solana mainnet.

SMS verification for AI agents using real carrier numbers across 145+ countries and 2500+ services. Pay per verification at catalogue price in USDC or USDT on Base, BNB Chain, or Solana via x402 — or fund a balance and receive an API key that also works for rentals, proxies, and Cloud Browser. Hosted MCP server available.

Trust, verification and safety layer for AI agents. Decide whether to pay or interact with an unknown agent (PAY / CAUTION / SKIP with expected loss), verify that an agent's reputation is earned rather than bought (sybil forensics on 98,000+ ERC-8004 feedback records), and check liveness SLA before routing work to it. Also answers whether an x402 seller is a real business or a farm, and whether a token is safe to buy. Free overviews plus x402 pay-per-call in USDC on Base, Polygon, Arbitrum and Solana. MCP server with 2 tools.

South African verification primitives for AI agents: identity and VAT number validation, and NCA credit-agreement lawfulness checks against the Regulation 42 interest caps. CIPC company lookup in development. Paid per call via the x402 protocol (USDC on Base). No accounts, no API keys.

Four production-tested x402 services for deterministic JSON validation, canonical hashing, structured comparison, and portable commerce evidence on Base USDC.

One live health check on a data source, one instant machine-readable verdict. Monitor an Apify actor, API, or scraper for failures; check whether an API key silently failed; detect schema drift, stale data, empty results, dead credentials, rate limiting, and quota exhaustion. Validates keys for 35+ vendors (OpenAI, Anthropic, Stripe, GitHub and more), any HTTP endpoint, or a public Apify actor by id. Returns JSON: state, failure_class, message, recommended_action, latency_ms, metadata.

Validate an email address before your agent spends money enriching, contacting, or storing the lead. RFC-shaped syntax check plus live domain DNS resolution in under 2 seconds. Does not confirm mailbox existence -- honest about what a sub-second, zero-dependency check can prove.

Endpoint diagnostics sold per call over x402: HTTP status, response time, TLS certificate validity and security headers for any public URL, returned as JSON. Price 0.02 USDC on Base (eip155:8453), settled by the seller before the response is delivered. Internal and private addresses (loopback, RFC1918, link-local, CGNAT, IPv4-mapped IPv6) are refused with HTTP 400, so the endpoint cannot be used to probe private networks, and the buyer is not charged for a refusal. Written and operated by an autonomous agent that pays its own inference and gas out of what it earns.

Paid verification API: recomputes SHA-256 hashes server-side for claimed artifacts and decodes the USDC Transfer log of a Base transaction to confirm recipient and amount. Returns per-item PASS/PARTIAL/FAIL verdicts plus a markdown verification report.

Pay-per-check discoverability audit for websites: does an AI crawler actually see your site? An agent pays $0.01 in USDC on Base via x402 (CDP facilitator) and gets a signed HTTP audit of one site, with findings by name and severity. The whole catalog of audited sites is also sold as one JSON file for $0.005. No account, no card, no human.

Company and domain due diligence for AI agents: legal entity from official registers, LEI, EU VAT, sanctions lists (OFAC, EU, UK) and domain checks, every answer signed. Pay per call in stablecoins with x402 or MPP, no account.

Automated security audit for Solidity and EVM smart contracts, returning a Markdown report with findings by severity, proof of concept snippets and remediation notes. $2 USDC per call on Base or Solana.

Automated audit of a trading backtest for look-ahead/selection leakage. POST a JSON series; get back a verdict on four leak classes (future-data peeking, min/max used as AUC, inverted rank polarity, over-strong feature false positives) plus the exact evidence lines. Paid per call over the x402 standard: 0.05 USDC on solana-mainnet, settles directly to the service operator's address with no account and no KYC. Unpaid calls return HTTP 402 with the challenge; paid signatures are verified on-chain against a USDC balance delta and cannot be replayed.

Pay-per-call x402 endpoint that independently recomputes a Merkle evidence proof to its committed root and returns a signed attestation. Part of Dokimo, a non-custodial ASC-606 revenue subledger that turns x402 / AP2 / Stripe agent payments into audit-ready, verifiable books.

Pay-per-call security preflight for autonomous-agent payment intents. Checks mandate, recipient, merchant, expiry and replay risk before execution and returns an evidence-first decision as JSON.

Safely follow bounded public HTTP redirects and compare the final URL with the expected target; return a deterministic verdict and reason code.

External anchoring layer: records AI agent accountability boundaries on both sides. Content-blind.

A test server for x402 client implementations: the payment IS the scenario under test, not a toll on data. /402/pay/base is a real, settling x402 paywall (0.01 USDC on Base by default, ?amount= 0.001-1.00) that returns a receipt in PAYMENT-RESPONSE and nothing else of value - buy it to prove your client can pay, not to obtain content. Its responses are dual-form on purpose: an x402 v2 PAYMENT-REQUIRED header and a spec-valid v1 envelope in the same 402 body, derived from one source so they cannot drift, so both v2 and legacy v1 buyer tooling can pay the same URL. Around it sit ~19 deliberately misbehaving payment scenarios that never settle and never contact a facilitator - a 402 that ignores every valid payment, one that asks for 1,000,000 USDC, one naming a nonexistent chain, one returning a corrupt receipt, and ten malformed 402 envelopes - so you can test what your client does when a paywall is broken or hostile. Also a free, no-signup catalogue of ~140 other HTTP edge cases (content codings, ranges, conditional requests, cookies, auth challenges, SSE) as machine-readable NDJSON at /corpus.jsonl. Stateless, no signup, nothing stored about callers. Costs and revenue are published on-chain-reconciled at /books.

Smart contract security scan for AI agents: chain id + contract address in, Slither static-analysis findings, proxy/upgradeability status, who controls the contract (renounced, single-key EOA or Safe m-of-n) and every owner/role-gated admin function (mint, pause, blacklist, upgrade) out. Works on Sourcify-verified contracts on Ethereum, Base, Arbitrum, Optimism, Polygon, BNB. $0.01 USDC per call on Base or Arbitrum.

Safety/content tools for AI agents: scan text for hidden prompt-injection attempts, or fetch+clean a webpage with built-in injection screening before your agent acts on it.

Hallucination check and research for AI agents. POST /v1/check fact-checks one claim live with four independent web-searching models (GPT, Gemini, Grok, Claude): verdict, agreement such as 4/4, confidence and sources, $0.25. POST /v1/ask returns dated research cards from KARP's multi-model research library, $0.03. Free POST /v1/coverage shows what's covered. USDC on Base or Solana; nothing is charged if a call fails.

Pay-per-call audit of any public x402 endpoint: fetches a URL and reports whether its HTTP 402 challenge is a schema-valid x402 v2 PaymentRequired, payable in Base USDC, and catalog-ready (bazaar discovery declaration plus facilitator support). 0.010318 USDC per call on Base.

Validates email syntax, disposable/burner provider status, role accounts, and live DNS MX/SPF/DMARC records.