x402-protocol-integration

Browse ERC-8004 registered AI agents on Base. Filter by x402 payment support.

x402 API activity stats — top endpoints by paid calls, trend data, and unique payer counts from memoryapi.org nginx logs.

Paid liveness probe for the MimirAPI counter. Returns pong, the SKU id, and a server timestamp. One tenth of a cent buys a complete challenge, sign, settle, serve round trip — the cheapest possible proof that your x402 client wiring works before you spend real money on real SKUs.

Cheapest endpoint: liveness plus x402 payment pipeline check — Returns ok with the server time and whether this call was paid. Use it to verify your x402 client end to end before spending on data endpoints.

Cheap connectivity-check endpoint. Verifies the full x402 settlement path (signature -> CDP facilitator -> on-chain transferWithAuthorization) for $0.01 so AI agents can validate wallet + network + facilitator wiring before committing to higher-value AML calls.

Quote an x402-paid API before you buy: probes a third-party endpoint with one unpaid GET (no payment is ever sent) and decodes its payment requirements — x402 v2 base64 PAYMENT-REQUIRED header or v1 JSON body. Returns normalised prices (atomic amount, asset, network, payTo), description, resource URL and Bazaar discovery metadata. Non-402 targets return {isX402:false, status}. SSRF-checked, 1 redirect max, 8 s timeout.

Agentic Market compatibility route. Uses Base x402 and returns HTTP 402 Payment Required when called without a valid x402 payment. Use the matching /mpp/v1/* route for Tempo MPP clients.

[BATCH+PROOF] x402 service graveyard - services that vanished from the census. THRESHOLD stated plainly: listed on FIRST confirmed absence (confirm_absences=1), NOT multi-day confirmation - only two snapshot days exist, which cannot support a streak test. Rows are hash-backed and recompute offline with ?verifiable=1; record_hash_verifiable reports the exact count per response. Descriptive only, never a forecast or advice. No data -> 422 no_charge, not billed.

Detect common SPF mechanisms present in a TXT record. Call when quick SPF mechanism inventory without DNS lookup. Returns flags for include/a/mx/all as deterministic JSON for $0.001 USDC via x402 on Base. First-party local math only—no RPC, live market feed, API keys, storage, or mediagen. Advisory only; the caller owns capital, risk, and production controls.

Preflight before paying an x402 service: is it working right now, and did it work the past 30 days? One live probe of the exact resource URL you intend to pay (status, latency, x402 validity, the payTo/price the service itself publishes in its 402, manifest presence) plus our own monitoring history of the host (30-day uptime, last check, recent changes such as payTo or price drift). Optionally verifies that the pay_to you intend to pay matches the live 402. Facts only — no scores.

[SUBSCRIPTION] Pay once to mint a STATELESS signed token (HMAC - no account, no login, no session, no server-side storage). Send it as Authorization Bearer on /gauge/watch and /gauge/watch-changes to read a batch watchlist without per-call payment. Default validity 30 days. The free tier is unaffected. Priced above the default agent maxValue on purpose - minting a subscription should be a deliberate act, not an accident.

x402 payment E2E test endpoint (echoes query). Factual data only; not investment advice.

x402 market intelligence time series: how many services/resources are listed per category (Agentic.Market taxonomy) or in total (CDP Bazaar ~23k resources, Agentic.Market ~1.5k services), sampled ~3x/day by our collector since 2026-07-06. Query category=Data|Inference|Search|... or category=all for catalog totals, days=1-30 window. Deterministic reads from our archived observation history; no upstream calls at request time. Free snapshot: /v1/market-pulse.

Raw observation history for any publicly listed x402 endpoint: discovery snapshots (listed/delisted/relisted, price changes, payTo changes) and probe time-series (uptime, latency, quoted amount) over the requested window (1-90 days).

Overall high-level facilitator stats

Full x402 market-intelligence report from a complete CDP Bazaar dump: demand-to-supply ratio for every tag with HOST CONCENTRATION so an incumbent's garden is not mistaken for an opening, price percentiles for resources that actually earn (broken out by category), the high-value tier charging $50-$3,208 per call, and calls-per-payer retention for the top 30 earning hosts. Answers what to build, what to charge, and what to avoid. Free preview at GET /intel/x402/preview.

Stratalize — attested finance, legal, healthcare, and compliance intelligence. Signed, independently verifiable receipt on every call (trust.stratalize.com/verify). Use when an x402 agent or DeFi developer needs current gas cost benchmarks for transaction planning. Returns Gwei, USD cost per transfer type, congestion category, and Base vs ETH savings comparison. Source: Chain RPCs live

OnRamperX is a non-custodial value router for agents and humans: fiat<->crypto and cross-chain via one quote interface (Coinbase Onramp v2, Relay, x402). This endpoint returns the router's live capabilities and rail status; use /api/x402/quote for a ranked route. Settlement centers on USDC on Base.

Uniswap v4 hook security scanner & rug-check API (Base mainnet). Pre-trade safety gate for DEX routers, token scanners and trading bots: decodes all 14 hook permission bits from the address (v4-core Hooks.sol), flags swap custody, fee-taking and EIP-1967 upgradeable hooks, verifies source via Basescan/Sourcify/Blockscout consensus. Returns custody class (PASSIVE|FLOW_CONTROL|FEE_TAKING|SWAP_CUSTODY|OPAQUE), risk flags, verification state. Capability analysis - never outputs SAFE. $0.01/call.

Vet an x402 server or any URL for scam/phishing/trust in ONE call: transport, content-safety, domain, metadata + x402-compliance sub-scores, each with transparent evidence

Three-source intelligence pack in one x402 call: equity market snapshot (SPY/QQQ/IWM/VIX/risk signal) + top DeFi yield pools by APY + top prediction markets by volume. Replaces three separate calls. $0.175 purchased individually; $0.15 as a pack. No inputs required.

Batch Base token safety, honeypot, rug-check and swap-preflight verdicts for up to 5 EVM contracts before a buyer agent signs or routes a swap. Returns PROCEED/CAUTION/REJECT actions, safety scores, evidence, warnings, aggregate counts, and a non-breaking 0.50 USDC bundled-risk-pack payable tier. Free single-token preview: /token-safety/free. Search keywords: rug check, honeypot check, token risk, swap preflight, rug pull, scam token, and is this token safe.

Name the endpoint paths for a service that will not self-describe; each is probed and only valid x402 endpoints are listed.

8 Things That Tripped Me Up Implementing x402