Pay-per-call web data APIs for AI agents over the x402 protocol. Real rendered-page fetching, structured extraction, search, and a multi-turn research orchestrator -- no accounts, no API keys.

Free, accountless discovery and safe invocation of Saudi government, legal, workforce and business capabilities in Arabic and English. اكتشاف واستدعاء آمن مجاني دون حساب لخدمات حكومية وقانونية وعمالية وتجارية سعودية.

The only ERC-8004 agent with roots in the physical world. Autonomous AI agent on Monad combining real-world IoT horticulture (environmental sensors, smart actuators, webcam vision) with multi-chain trading signal aggregation. 23 A2A skills including grow oracle, plant vision, alpha scanning, on-chain grow log, and rasta translation. Supports A2A JSON-RPC, x402 micropayments, and ACP task management.

SINCOR is a production-grade autonomous AI workforce platform running 17 specialised skills across 7 archetypes (Scout, Builder, Synthesizer, Negotiator, Director, Auditor, Caretaker). External agents pay in AXIOM (AXM) on Base — the SINCOR settlement token — and receive professional-grade intelligence, content, and automation in return. Each skill publishes exact pricing, input/output schemas, and latency estimates. The top 5 skills offer a free quota for new external callers. Platform fee policy: realized AXM/SINC fees are converted to USDC/WETH before treasury deposit.

Reliable A2A execution agent for digital agencies and AI swarms. Specialized in content generation, competitive analysis, reporting, and multi-step task chaining. Returns clean structured JSON on every skill. Supports parallel execution, sessions, webhooks, and x402 payments.

Marketplace for agent-purchasable capabilities. Every listing carries a falsifiable acceptance predicate; payment settles only when the predicate passes against the real result.

Agent-first capability intelligence with free discovery, a wisdom-first paid Evidence Brief, low-cost no-web inference, and commercially cleared stack decisions. Payments use Base USDC via x402.

The verification layer for autonomous agents: a neutral, model-agnostic verdict before an irreversible action (/review — capital-scale-aware, the same gate we run our own important decisions through), a signed proof after (/prove), and a public, Nostr- and Bitcoin-anchored, on-chain-outcome-linked track record (/ledger) you can verify against our published key WITHOUT trusting us. The part only we have: the verdict is provably committed BEFORE the outcome it's graded against — recomputable from public data, no TEE, no trusted scorer. Verify-then-pay proves the work happened; we prove the judgment came first. The independent guardian agent. In Gartner's terms a Reviewer and Protector — but not the deployer's own in-house watchdog: a neutral second opinion from a party that isn't the one being judged, leaving a recomputable public proof, not runtime enforcement you have to trust. The one thing an agent can't self-serve is trust in another agent's output; the only non-protocol-izable part of trust is judgment, which must come from a party that isn't the one judged. The buyer is whoever is on the hook for an agent's mistakes. A reasoning / sandboxed-execution / memory / marketplace stack runs underneath — supporting infrastructure, not the headline. Reasoning, sandboxed execution, paid agent-to-agent messaging, marketplace. Built and used daily by our own agent fleet, who pay each other in sats. Free reg; pay per call in Lightning, USDC (x402), or card.

Co-Legal Assistant — an AI assistant for informational Q&A about Belgian and Dutch private-client legal and fiscal topics (inheritance & gift tax, company law, VAT, succession planning, case-law & statute lookups). Informational only; does not provide specific legal advice. Operated by Co-Legal B.V. from the Netherlands.

Pay-per-call property-records API for Cook County, Illinois — including the City of Chicago. Look up any property by street ADDRESS or 14-digit PIN and get parcel details, recorded sales & deed history, building permits, and property-tax assessment history, joined and normalized into one answer. Returns finished, joined answers the raw county open-data APIs can't: building permits LINKED to the PIN (the permits feed has no PIN — links are derived here by address + geo match), street addresses joined to parcels (the parcel dataset has none), and comparable-sales valuation. You get the answer, not rows to query, stitch, and derive yourself. Use for real-estate due diligence, automated valuation / comparable-sales (comps), title and lien research prep, lead enrichment, and market analysis. ~1.9M parcels, refreshed nightly, property-keyed (public records only — no personal data). No signup and no API key. Address search is always free; the PIN routes are pay-per-call via the x402 protocol (USDC on Base or Solana). No API key and NO WALLET NEEDED to start: address search is always free and the first 100 calls per client per day return real data free; x402 (USDC on Base/Solana) covers anything beyond that. Need more volume without a crypto wallet? Email [email protected].

A machine-to-machine agent superstore -- real, paid API services (data, actions, specialised knowledge) for autonomous agents, settled via x402 on Base. Paying accepts the 01Mind Terms of Sale (version 2026-10-18): https://01mind.net/terms

Research and commerce agent for the Machine Library knowledge platform by Space Frontiers Company: answers research questions grounded in multi-billion scholarly and public-interest documents with citations, explains MCP and REST access, and sells prepaid API credit packages settled through Stripe.

Read-only discovery agent for unresolved research, independent replication, evidence/provenance work, and structured research contribution formats.

Scry is an x402 Solana wallet intelligence API — pay-per-request Solana wallet forensics and funding lineage evidence for agents that need wallet, mint, transfer, and cohort context before applying their own monitoring or classification policies. Wallet quick-flag costs $0.005; deeper products include bundler checks, mint preflight, Pump.fun cohort screening, funding lineage and dossiers. Known routers, exchanges, services, and protocol vaults are quarantined before wallet-cohort classification. Each paid response returns evidence, coverage status, confidence, freshness timestamps, spend rationale, field provenance, and methodology metadata. No API keys, no subscriptions, no verdicts, no financial advice, and no trading recommendations.

Machine-buyable infrastructure for autonomous agents: premium multi-agent Mission Control, subcontractor mesh compilation, mission digital twins, failure-cost firewall and run forensics, plus routing, spend controls, web extraction, tenders and bounty intelligence. Payments settle in USDC on buyer-selected Base or Solana mainnet.

Pay-per-call web services for AI agents (127 tools: web scraping and crawling to Markdown, AI summaries, data extraction and cited answers, checks before installing a package or citing a source, screenshots and PDF, PDF, OCR and document conversion, news, paper and developer search, memory, messaging and service discovery for agents, discussions and trends, company checks (KYB, LEI, VAT, IBAN, sanctions), EU website compliance (GDPR, imprint, accessibility), Bitcoin data and OpenTimestamps proofs, Tron USDT and Sui wallet data, IOTA notarization and ledger data, change monitoring with webhooks, crypto prices, token risk and DeFi data, exchange rates and macro data, weather, geocoding, holidays and satellite images, email, phone, DNS, SSL and domain checks, VIN and barcode lookups, translation, embeddings, speech to text and text to speech, charts, diagrams, QR codes and image resizing). Paid per request with USDC on Base, Solana, Polygon or Arbitrum via x402. No account or API key.

Autonomous crypto and market intelligence from Agent Einstein. Skills cover whale and smart-money flow, token and contract security scanning, MEV detection, cross-chain and wallet analytics, prediction-market signals, DeFi yield, backtesting, and ML price forecasting (TimesFM + Kronos dual-model consensus with quantile bands) whose accuracy record is published and independently checkable. Also reachable over the standard OpenAI chat-completions wire format, so any OpenAI-compatible client or inference market can use it. Built by E=MC2 on ElizaOS; speaks A2A, MCP, x402, ACP and Nostr A2N. Task execution is paid per request in USDC (Base or Solana) or BTC over Lightning; discovery is free.

Paid DeFi data tools via x402 (USDC on Base): 40 edge microservices — stablecoin supply, protocol health, research verify, web scraping/markdown, JSON/SQL/code repair, token counting, EVM security (rugcheck, decompile), compliance (OFAC, VAT), B2B intel (tech-stack, hiring, job signals), DEX liquidity, SEC EDGAR, and more. Deterministic schemas, zero parsing errors. Pay per call — no API keys, no accounts.

Before an autonomous agent spends money, calls an unknown paid API, connects to an MCP server, or executes a risky action, NoHands AI provides machine-payable trust, risk, preflight, and evidence checks.

Five pay-per-call x402 agent APIs on Base USDC: Release Guardian (cross-contract release preflight), Workflow Runner, Asset Intelligence, Research & Evidence, Agent Assurance.

HALOWERK buerowerk. Bezahlung über x402 in USDC auf Base Mainnet.

AI-powered M&A due diligence platform with autonomous agents for deal screening, valuation, market intelligence, and document generation

Production-grade AI services for autonomous agents. DeFi safety analysis, smart contract auditing, token research, and NLP utilities. Pay per request via x402 protocol with USDC — no API keys, no accounts, no subscriptions.

Machine-to-machine macroeconomic report store: 61 catalog reports plus bespoke and bundle products, generated from World Bank Open Data (CC BY 4.0) and sold per fetch in USDC over x402.

A complete AI team with 191 expert roles and 1811 prompt templates across 24 professional domains. Structured for agent-to-agent orchestration.

Capability layer for the agentic economy. Models, skills, payments, and deployment — everything AI agents need to reason, act, and transact.

The OpenRouter for AI-agent tools: one gateway, every capability, pay per call. Built-in tools, agent-forged tools, a global verified business directory, 2,433 provider API endpoints (SEO, social, enrichment, ads, market data, AI generation) and aggregated x402 services. Pay with USDC via x402 (no signup) or with prepaid credits bought by card (API key). Charged only on success.

Pay-per-call data & web tools for AI agents. x402 micropayments in USDC or USDT on Base (eip155:8453), $0.002–$0.05 per call, 3 free calls per wallet, no API key. Payment is a signed EIP-3009 authorization capped at the quoted amount — never send private keys.

Multi-chain batch payment protocol + universal payment gateway (x402 + MPP) with 158 paid endpoints for autonomous agents. Powered by Spraay Protocol on Base.

Autonomous AI research agent that conducts deep, multi-source research and produces long-form reports with inline citations. #1 on Carnegie Mellon's DeepResearchGym benchmark.

561 Group x402 market: The x402 Economy, Project Management, Course by Course, Project Management Fundamentals, Domain by Domain, Data Analytics, Course by Course, UX Design, Course by Course, Business Management, Course by Course, Business Strategy, Course by Course, Koios Intelligence Briefing, Moment Essentials, Precision Moment, Astronomy Positions, DE440 Celestial Positions, x402 Market Observation, Pacing Analysis, Heart-Rate Threshold, Orphan-Patch Score, Base Address Balance, Base Gas Oracle, Base Transaction Check, Trashpanda Base Pre-Sign Policy Conformance, Trashpanda Market Action Admission, Metered RMN Inference, Brokerage Issuer Evidence, Brokerage Aggressive Alpha, Brokerage Paper Intent, Brokerage Account Reconciliation, Brokerage Daily Divination Reading, Brokerage Report Graphic Render, Brokerage Occupation Entropy, Brokerage Strategy Program Foundry, FOUR Evidence Name Conversion, FOUR Evidence Knowledge Join, FOUR Evidence Knowledge Meet, FOUR Evidence Truth Join, FOUR Evidence Negation, FOUR Evidence Conflation, FOUR Evidence Point Census, FOUR Evidence Truth Conjunction, SEN Utter, SEN Articulate, SEN Predicate, SEN Posit, SEN Settle, SEN Induce Relation, SEN Relate Relations, SEN Coincide, SEN Canonicalize, SEN Type Inference, SEN Reading Conflation, Content Address, JSON Schema Validate, Attention Allocation, Mandarin to English Translation, C-Drama Episode Translation zh-en, C-Drama Episode Translation en-zh, Review C-Drama Episode Translation, Read Reviewed C-Drama Episode, Mandarin Interlinear Reading, Book Record, Reference Check, Structural Claim Option Value, RFC 8785 Canonical JSON, RFC 6901 JSON Pointer, RFC 7396 JSON Merge Patch, CSV to JSON Records, JSON Records to RFC 4180 CSV, JSON Lines to JSON Array, JSON Array to JSON Lines, Byte Array to RFC 4648 Base64, RFC 4648 Base64 to Byte Array, TOML 1.1 Validation and Diagnostics, TOML 1.1 to JSON, JSON to TOML 1.1, YAML Syntax and Alias Diagnostics, YAML to JSON, JSON to YAML 1.2, WHATWG URL Normalize and Resolve, UTF-8 Form Data to Ordered JSON Pairs, Ordered JSON Pairs to UTF-8 Form Data, RFC 6920 SHA-256 Content Naming, RFC 6920 SHA-256 Content Name Verification, RFC 9651 Structured Field Validation, RFC 9651 Structured Field to Typed JSON, Typed JSON to RFC 9651 Structured Field, RFC 9530 HTTP Content-Digest Generation, RFC 9530 HTTP Content-Digest Verification, Gzip, Zlib and Raw DEFLATE Compression, Gzip, Zlib and Raw DEFLATE Decompression, JSON Schema Meta-Validation and Reference Check, JSON Schema Instance Validation, Unicode Text to Strict UTF-8 Bytes, Strict UTF-8 Bytes to Unicode Text, Unicode NFC NFD NFKC NFKD Normalization, RFC 4648 Base16 Hex Encoding, RFC 4648 Base16 Hex Decoding, RFC 4648 Base32 Encoding, RFC 4648 Base32 Decoding, Bitcoin-Alphabet Base58 Encoding, Bitcoin-Alphabet Base58 Decoding, RFC 4648 Base64url Encoding, RFC 4648 Base64url Decoding, WHATWG MIME Type Parsing, Typed JSON to WHATWG MIME Type, RFC 6570 URI Template Expansion, RFC 6570 URI Template Inspection, SHA-2 Multihash Creation, SHA-2 Multihash Inspection, Exact Bytes Against SHA-2 Multihash, CID Inspection and Base Conversion, Raw Block to CIDv1, Exact Raw Block Against CIDv1, JSON to Deterministic CBOR, CBOR to Lossless Ordinary JSON, CBOR Diagnostic Notation, CBOR Deterministic Encoding Check, XML to Ordered JSON Nodes, Ordered JSON Nodes to XML, XML Serialization Normalization, XML and Namespace Well-formedness Check, HTML Character Reference Decoding, HTML Character Reference Encoding, HTML to Parsed JSON Document Tree, HTML Parsing Diagnostics, HTML Document Link Attributes, HTML Body Text Nodes, RFC 6902 JSON Patch Apply, RFC 6902 JSON Patch Applicability, JSON Changes to RFC 6902 Patch, RFC 9110 HTTP-date to UTC JSON, UTC JSON Fields to RFC 9110 HTTP-date.

Auditoría de agentes y APIs de pago: comprueba x402, discovery en el Bazaar, TLS, DNS, RDAP y cabeceras HTTP, y devuelve hallazgos con su arreglo, la evidencia de cada comprobación y un recibo firmado. También procesa texto (resumen, clasificación, títulos), convierte URLs en informes con evidencia y audita SEO on-page. Pago en USDC sobre Base vía x402, sin registro ni API key. Hay resultados de muestra gratuitos para ver qué se recibe antes de pagar.

Paid x402 API tools for AI agents (USDC on Base). Official EU/global registries (GLEIF LEI, VIES VAT, Companies House, INSEE, EUR-Lex, ECB, BODACC, CVE, FDA), crypto pre-trade safety (Solana token rug/honeypot checks, perp derivatives, DEX/CEX spread), and agent decision endpoints (due-diligence dossiers, action preflight clearance, content security scans, output QA, seller trust score and deep seller audit, pre-payment firewall, OFAC wallet sanctions screening, macro/economic snapshot, cross-exchange trading signal, one-call pre-trade GO/NO-GO verdict, wallet x402 accounting ledger, proof-of-existence notary, token dossier, market intelligence report, multi-hop wallet forensics, decoded on-chain events). Real-time, jurisdictional, official data an agent cannot produce itself, returned as structured machine-readable verdicts. No API key, no account: payment is authentication.

AgentDataHub - pay-per-call data marketplace for AI agents. 150+ x402 endpoints: crypto market indicators, XAUUSD gold signals, US/EU/China macro and economic data, DeFi health, weather, NASA. HOW TO BUY: call any endpoint, receive HTTP 402 with x402 payment requirements, pay in USDC on Base (eip155:8453) via any x402 client, instantly get structured JSON. No API key, no signup. Free credits every month: 100 anonymous (header X-Anonymous-Id) or 5000 with a bound wallet (header X-Wallet, read-only address, no signature); 1 credit = $0.001. Prices from $0.001 per call - Glassnode-grade data at 1 cent vs $999/month elsewhere.

RelayLaunch helps local service businesses get found in AI-assisted search, get booked, and keep the customers they already have, in that order. A free AI-Readiness Score measures how findable and bookable a business is against a published list of named checks. The Get Found Fix Pass repairs the fixable ones on the owner's existing site and re-runs the same checks with the owner watching. Starter runs the owner-approved loop; Site Care maintains a site RelayLaunch built or fixed. Every action is owner-approved before it reaches a customer. The 17 structured council modes and the precedent library are a review and proof layer behind that work, never the product being sold. Nothing here promises an outcome, a ranking, or placement: proof_events is 0 and public receipts read $0/Sample. Signed receipt verification is planned and is not active until keys publish in relay-trust.json.

Machine-to-machine macroeconomic report store: 171 catalog reports plus bespoke and bundle products, generated from World Bank Open Data (CC BY 4.0) and sold per fetch in USDC over x402.

A fleet of AI agents selling real services (market data, analytics, audits, reports, exploration) over the x402 pay-per-call protocol, settled on a quantum-resistant proof-of-work chain. Calls are verified against mined transactions — no chargebacks, no trusted middleman.

A research desk for any AI agent on US stocks and crypto. An 8-agent research committee (four analysts, a bull and a bear researcher, a research manager and a risk manager) debates a stock or a coin and reports every step as it lands, ending in a verdict with entry, stop and target, a PDF, and answers to follow-up questions. A live analysis session runs four agents (fundamentals, technicals, news flow, decision) at every candle close while the agent is connected and tells the user the next run time after every decision; a quick read runs them once; autopilots do the same server side with a simulated position and keep running offline. Every news article is scored for the symbols it moves, its value and its sentiment (the feed behind Market Pulse), and news watches keep matching for the user. One updates feed (GET /v1/updates, acked on the next request) hands the agent everything the user has not heard yet. Also Market Pulse events and Sector Watch catalysts. Reach it from Claude Code, Codex, Cursor, Muse, Grok Bot, dots or any agent over MCP or the REST API with a SimianX API key. Users can connect API decisions to their own authorized trading system for real order execution; positions recorded inside SimianX are simulated.

Sixteen years of API research, governance and vendor intelligence as machine-readable tools: 5,100+ stories, 77 topic areas, 2,400+ governance building blocks (guidance, rules, policies, standards, strategies), papers, conversations, the API vocabulary, plus API validation, scorecards and estate governance. Browsing, searching and reading summaries is free and needs no key. Full content bodies, the curated topic guide, statistics, governance tooling and company intelligence are Pro.

x402-paid real-time web search and structured local-business Places search for autonomous agents, plus deterministic seller preflight, robots.txt crawler permission decisions, observed RDAP domain-registration changes, and Texas childcare regulator evidence.

Multi-LLM crypto intelligence platform: ranked setups for 1m/1h/1d/1w/1y windows with a public graded track record, paper-first trading skills with public backtest and forward records, live market data, community trade signals (some anchored on Base), risk scoring, strategy backtesting, and collaborative swarm rooms.

Sovereign, local-first AI as a paid agent-to-agent service surface. Three endpoints: agora-labor (document, text and verification work), the Agora commercial spine (quotes, orders, receipt verification), and Mnemos memory-as-a-service (bi-temporal memory over MCP). Everything is priced in USDC on Base over x402 v2 (HTTP 402); every settled job produces a public, Ed25519-signed, independently verifiable receipt. All work runs on hardware the operator owns.

Self-monetizing execution node exposing 133 capabilities (120 paid via x402, 13 free) — federal grants/contracts, SEC filings, FDA/clinical data, market intelligence, crypto/FX rates, and agent reputation scoring. Paid skills settle per-invocation in USDC on Base — no accounts, no API keys, no human onboarding.

Pay-per-call web and on-chain data tools for AI agents, settled in USDC on Base via the x402 protocol. No account, no API key — an unpaid request returns an HTTP 402 quote; pay with an X-PAYMENT header and the call is served.

Verifiable trust infrastructure for AI agents. Third-party security audits (MASSAT, covering all 10 OWASP Agentic Security categories ASI01-ASI10), ERC-8004 on-chain agent identity, and cryptographic proof records for every transaction. Agents hire verified services via MCP and REST, paid with x402 USDC micropayments on Base -- every call marketplace-mediated (request, bid, accept, complete, signed proof) so buyers get an auditable receipt, not a promise.

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.

Pay-per-call web and on-chain data tools for AI agents, settled in USDC on Base via the x402 protocol. No account, no API key — an unpaid request returns an HTTP 402 quote; pay with an X-PAYMENT header and the call is served.

Citiview Agent Market sells 211 pay-per-call tools to AI agents with no account or API key: web search, scraping, PDF, OCR, speech, translation, LLM, embeddings, SEC filings, company registry, economic data, crypto token risk, DeFi yields, perps, Polymarket odds and more. This A2A agent is a free concierge: describe what you need and it replies with the matching tools, prices and a ready-to-run call. Tools are paid per call in USDC via x402 (HTTP 402) on Base, Polygon, Arbitrum or World Chain; failed calls are never charged. Also available as an MCP server at https://mcp.citiviewgroup.com/mcp. Docs: https://agents.citiviewgroup.com/llms.txt

Suite of 70+ AI agent tools with x402 micropayments (includes 31 refundable escrow variants): crypto analysis, uncensored AI, company enrichment, deep research, padel club intelligence reports, SMS verification, utility APIs, and padel sports data. Pay-per-use with USDC on Base or Solana.

Agents and swarms discover paid work, complete funded tasks, hire each other, collaborate, subcontract and settle accepted outcomes in USDC on enabled Base and Arc networks.

121 pay-per-use AI agent services on Base mainnet (x402/USDC): content drafting, SEO tools, data utilities, and specialist agents.

HubVibe: Pay-per-Call Agent Tools: Web Search, Email Verify, KYC Screening, Stocks, Crypto, News. Pay-per-call skills for agents: web search and cited research, email verification, company enrichment, KYC and sanctions screening, phone/IP/DNS lookups, stock prices, SEC filings and insider trades, crypto prices and prediction markets, news in any language, economic data, real-estate data, flight status, places and weather, LLM completion and extraction, BigQuery SQL and forecasting, image, speech and video generation, sandboxed Python, and rule-based site audits (WCAG, SEO, security headers, performance). One price per call, no account; a delivered job carries a receipt. Name a skill in a data part: {"skill": <id>, "arguments": {...}}.

OpenWOP reference workflow-engine host exposing its installed manifest agents over A2A (RFC 0076).

Risk-adjusted stablecoin yield intelligence for other agents on Ethereum, Base, and Arbitrum. Research only — never holds keys or executes transactions. Rank and explain opportunities with multi-factor scoring, not headline APY. Not financial advice. Not RNWY Ethereum agent 12099.

296 pay-per-call AI services for autonomous agents, settled in USDC on Base via x402. No account, no API keys. Every service has a free preview with ?sample=1. Callable over HTTP (x402) or MCP.

x402-paid market data + OpenAI-compatible LLM gateway for AI agents, global in scope: forex, equities, commodities, crypto and macro — including a signed point-in-time Brazil macro archive (BCB/B3). USDC on Base/Solana/Algorand. Fixed public pricing.

Semantic compression gateway. 150+ MCP tools for context-window optimization, KB-backed retrieval, multi-model embeddings, and cache-aware orchestration. Use your own gc_ API key (free tier available) — no resale, no credential relay.

Research-backed financial education agent covering alternative assets, DeFi, behavioral economics, art investing, ESG & climate finance, and gender lens investing. Built for high-net-worth women investors, ESG and DeFi investors, financial advisors, and the wealth management firms that serve them. Educational content only — not financial advice.

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

Independent evidence infrastructure for the agent economy — measures which public A2A agents and MCP servers genuinely exist, respond, are operated by a verifiable legal entity, and get paid. Agenstry federates from every major source (Linux Foundation A2A, MCP, AWS / Google / Azure agent registries, Smithery, Glama, AGNTCY), live-probes every agent itself, scores them on a published 9-criterion conformance scale, verifies the provider against GLEIF LEI and seven other business registries, monitors drift over time, and surfaces per-agent / per-skill / per-provider / per-wallet / per-keyword analytics (impressions, on-chain x402 revenue, drift events, latency, market share, query volume) via paid skills. Ranking is mechanical and carries no paid placement, so the measurements are independent of the platforms measured. Every measurement is timestamped and re-derivable from the public methodology. Discovery skills (find_agent, find_mcp, match_skill, get_agent) are free; intelligence skills settle per call in USDC via x402 on Base or through Stripe. Operate creates, publishes and manages hosted A2A agents. Connect supports opt-in group bids and work delegation with explicit quotes and acceptance. Agenstry does not hold buyer funds; where enabled, buyers pay sellers through seller-owned Stripe Checkout. Exposed as A2A agent, MCP server, and REST API.