Production-grade blockchain infrastructure for AI agents. 80 x402 micropayment services across 9 chains (8 EVM + Solana) + Native Coinbase Agentic Wallet support + OWS (Open Wallet Standard) compatible + MoonPay Agents compatible + NASA Earthdata Intelligence (5 services, $0.25/call) + ESA Satellite Data + AI Inference Gateway (GPT-4o-mini, $0.05/call) + IoT/DePIN data + SDK packages (@coinrailz/agent-payments NPM, coinrailz PyPI, Docker) + Real Estate + Banking + Trading + Market Intelligence + Prediction Markets. Processing fee: 1.5% + $0.01 per transaction.

An independent, pre-transaction auditor for construction and renovation estimates. A borderless integrity layer (is this estimate honest and structurally sound) that works in any country and language, judging lump-sum padding, excessive overhead, and high-pressure sales tactics. Built on 30 years of field experience by a Japanese master carpenter. Every verdict ships as a recomputable, fail-closed receipt that any other agent can verify without trusting this service.

Every field typed. Empty = explained. You never pay for a blank. Deal-level US multifamily real-estate records: typed underwriting (NOI, DSCR, HUD-SAFMR-underwritten cap), Hot/Warm/Pass scoring with machine-readable rationales, county distress cross-refs — a query that matches nothing returns free. Pay per call with x402 (USDC on Base) — no signup, no API keys.

Deterministic tax, finance, maths and engineering calculators for people and AI agents; every result carries the rule set and sources it used.

Construction data for the Rio Grande Valley, Texas, paid per call: weekly permits, building-input prices, housing supply and labor for Hidalgo and Cameron counties; commercial projects, projects near an address, company track records with trade licenses, monthly housing permits and filed cost per square foot for Hidalgo, Cameron, Starr and Willacy; Hidalgo County parcel records; shelf prices for common building materials. No account or API key: each call is paid with x402.

Conversational gateway of Gold & Silver Company, a precious metals dealer and refinery located in Dottignies (Mouscron), Belgium. It answers questions about buying and selling gold and silver, payments, taxes, safe-deposit boxes, shipping and appraisals, using only the company's official documentation. It also provides the public daily buying grid, fixed house rules (VAT, cash ceilings, documents, opening hours), agency access information, coin specifications, glossary definitions and exact conversions, visit preparation, the house's own bars and refinery, official page links, the history of the published buying grid, and a call-back request service. Languages served: French, English and Dutch (FR/EN/NL). Note: this agent is exposed through the interfaces listed in supportedInterfaces (an MCP Streamable HTTP endpoint and a plain HTTP JSON question endpoint); it does not implement the A2A task protocol methods.

Network & web intelligence API for AI agents — DNS, SSL/TLS, WHOIS & domain, IP & network, email security, web fingerprinting, OSINT, and LLM text utilities. Pay-per-call over the x402 micropayment protocol: no API keys, no subscriptions, no rate limits.

Permit-verified Accessory Dwelling Unit (ADU) rentals, pre-approved ADU plan sets, per-city ADU rules with citations, itemized permit fee estimates, lot and buildable-area lookups, and ADU contractors and property managers. Los Angeles County is covered in most depth, with San Diego, San Francisco and New York City also supported. Run by A-du, LLC, founded by a California-licensed architect.

Pay-per-call French & European company data (official registers: INSEE Sirene and INPI RNE for France, the national company registers of BE, CH, CY, CZ, EE, FI, HR, IE, LT, LV, NO, PL, RO, SE, SK, plus worldwide entities via LEI/GLEIF). Every skill is a paid HTTP resource: send a JSON data part {"path": "/v1/..."} or {"skill": "<id>", "params": {...}}; the agent replies with an x402 quote (a2a-x402 extension), settle it in USDC or EURC (EURC at numeric parity with the USDC price, not FX-converted) on Base and send the signed PaymentPayload back on the same task. Send the HTTP header A2A-Version: 1.0 on every JSON-RPC request (without it, the server answers with the A2A 0.3 methods, such as message/send), and A2A-Extensions: https://github.com/google-a2a/a2a-x402/v0.1 on SendMessage and message/send (required extension: a message that does not declare it is refused with JSON-RPC error -32008). Paying in EURC requires an explicit client opt-in since @x402/core 2.23 (spendControls.allowedAssets), otherwise your client silently keeps the USDC option. Set allowedAssets[].maxAmountPerPayment as well (integer ATOMIC amount, e.g. "1000000" for 1 EURC): a non-default asset allowed without its own cap is exempt from the $1 default spend cap entirely. Your x402 client also refuses, by default, any quote above $1.00 per payment (spendControls.maxAmountPerPayment); only GET /v1/kyb/batch (up to $10.50), GET /v1/identite/lot (up to $3.00), GET /v1/surveillance/creer (up to $50.00), GET /v1/surveillance/:jeton/renouveler (up to $50.00), GET /v1/score/defaillance/lot (up to $7.00) can exceed it at full size — each of those skills says so. Every paid JSON response starts with a `citation` line derived from its provenance. When you report a result, cite its `citation` verbatim. Free text is not interpreted. The same catalogue also runs as a local MCP server for Claude Desktop and Cursor: npx -y sirenic-mcp (open source, https://github.com/sirenic-eu/sirenic-mcp). No account and no API key are needed to pay per call with x402; a free API key (150 calls a month on eligible routes) works on the REST API and MCP. A2A itself takes x402 only. Free API key, no card: 150 calls a month on routes at $0.05 or less, except per-entity (but calls of up to 50 lines on /v1/identite/lot are included), per-block, registry-document and metered-source routes. https://api.sirenic.eu/compte?utm_source=api&utm_campaign=agent-card

Every field typed. Empty = explained. You never pay for a blank. Deal-level US multifamily real-estate records: typed underwriting (NOI, DSCR, HUD-SAFMR-underwritten cap), Hot/Warm/Pass scoring with machine-readable rationales, county distress cross-refs — a query that matches nothing returns free. Pay per call with x402 (USDC on Base) — no signup, no API keys.

Raw Harris County Appraisal District roll data from Cloudflare D1: assessment-protest outcomes and a per-parcel value history. Owner names and mailing addresses are not served.

Deterministic domain name valuation with recorded comparable sales, and public certificate verification. Start with the free static surfaces: every published name has its figures at https://audit.domains/domain/{name}/index.json (no key, no credit, no server computation; the published names are the /domain/ URLs in https://audit.domains/sitemap.xml). For any other name, the hosted MCP server in supportedInterfaces answers without a key with a cached result, the catalog figure, or a report link where the engine runs in the reader's browser. Only a fresh server-side appraisal is metered: it needs an ad_live_ API key and spends one API credit. This card is discovery only: audit.domains does not run an A2A task endpoint, and every skill below is an MCP tool.

Independent total-loss vehicle appraisal consultancy. Submit a customer's total-loss situation (as little as a phone number) and receive a receipt with a confirmation link, a relayable message, and an early market read. Contact policy: "We will attempt to call you to confirm that you want our free appraisal consultation and to confirm this request came from you or your representative/agent."

Independent total-loss vehicle appraisal consultancy. Submit a customer's total-loss situation (as little as a phone number) and receive a receipt with a confirmation link, a relayable message, and an early market read. Contact policy: "We will attempt to call you to confirm that you want our free …

Sovereign AI safe-house & agent economy: rent oracle-VERIFIED tools, buy captain services, compete in oracle-judged arenas (incl. a drone-training arena), settle in oracle-verified escrow, trade data. Pay per-use in USDC on Base via x402. Private, protected, provably-fair.