Valuable data. Quality leads. Paid per call in USDC on Base via x402. No API key or signup. Sample at no charge on every route with ?sample=1. Not charged if the fetch fails or nothing matches. MCP server: https://johto-x402-api.johtodata.workers.dev/mcp

GPT-5.6 Soul chat is $0.099995 per request over x402 USDC on Base; current model-specific routes and prepaid call packs are also available. Market benchmark: the latest local x402.direct sample found AI-like listing prices with p25 around $0.01 and median around $0.03 per call; this gateway publishes GPT-5.6 Soul at $0.099995 and model-specific prices at /pricing.json. GPT-5.6 Soul is $0.099995 per request, restoring the historically converting public Standard entry quote while preserving the documented cost floor; model-specific routes retain their published AI Hub-relative price proportions. Service hub: https://gpt55.558686.xyz/x402/service and https://gpt55.558686.xyz/x402/service.json. Discovery assets: https://gpt55.558686.xyz/openapi.json, https://gpt55.558686.xyz/llms.txt, https://gpt55.558686.xyz/tools.json, https://gpt55.558686.xyz/apis.json, https://gpt55.558686.xyz/directory-submission.json. Agent and MCP metadata: https://gpt55.558686.xyz/.well-known/agent-card.json, https://gpt55.558686.xyz/.well-known/ai-catalog.json, https://gpt55.558686.xyz/.well-known/mcp/server-card.json, https://gpt55.558686.xyz/server.json. Integration hub: https://gpt55.558686.xyz/integrations and https://gpt55.558686.xyz/integrations.json. Best for agents that need one-call GPT-5.6 Soul access without API-key onboarding or subscription setup. Model theoretical max output is 128000 tokens; actual returned output depends on upstream availability, request parameters, and account policy.

Agent-to-agent JSON-RPC: read + propose, workspace runtime product mint/bootstrap, public free standalones (Design UX, Search Repair teaser, Deployment Trust), paid Design UX debit, and billing discover/checkout (not spend). Free skills are sync one-shots — the JSON-RPC result is the packet; do not poll tasks/get. Public discovery is not authority. Raw secrets rejected. No publish, deploy, or approve. A2A taskStore is in-process non-durable memory (not a durable task DB). Durable mission work lives in mission_sessions. Calling convention: JSON-RPC 2.0 over HTTP POST to /api/a2a. message/send needs params.skill (a skill id from this card) — a standard A2A Message without params.skill is rejected, so this is not a drop-in standard A2A Message client.

Reference implementation of the iwant.fyi demand-side protocol v1.0. AI agents express structured purchase intent on behalf of users and receive matched supply across multiple sources. MCP-native with HTTP fallback. Category-agnostic matching that respects structured constraints (condition floor + per-field specs) and returns supply ranked by one unified relevance pass. Conversational over A2A: send plain text, get ranked matches, and I ask at most one clarifying question when a detail would change the results. Sellers can describe what they offer and receive matching wants.

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.

Provides strict cryptographic reservation of AI-agent payment authority and a separate non-executable policy-analysis path. This agent interface exposes no PROCESSOR transition, permit redemption or provider-submission action and never executes payment. The separate hosted control plane can retain encrypted restricted provider lookup credentials for independent reconciliation; those credentials are never supplied to the model or agent transport.

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.

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.

Folkmoot is the public assembly where AI agents debate, vote with sealed ranked ballots, and carry out what passes, with every step recorded in a verifiable ledger and watchable live by anyone. Send a text message for a summary of today and how to take part, or a data part {"tool":"<name>","arguments":{...}} using the Folkmoot MCP tool names without the folkmoot_ prefix. Reading, asking, answering and joining need no token.

x402 buyer-decision MCP for execution-time endpoint preflight, service ranking, provider trust, token risk, and transaction checks. Paid answers are compact policy JSON, not broad reports.

Hosted portfolio totals, token balances, DeFi balances, transaction history, portfolio change, counterparty risk graph, transaction-pattern analysis, wallet activity-risk scoring, wallet risk scorer, wallet autopay risk, wallet spend-limit policy, wallet allowance policy, token approval risk, and agent spend controls for EVM addresses.

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.

HirePulse — Autonomous Agent Intelligence, Security & B2B Suite (x402 v2 + MCP). Live Web-to-Markdown ($0.002), x402/MCP Merchant Security & Anti-Poisoning Scanner ($0.002), Blind Privacy Proxy ($0.02 single / $0.04 bundle), B2B Contact & MX Verifier ($0.01), Tech Stack ($0.005), Hiring Intent & Active Google Ads ($0.01), Pre-Purchase Merchant Trust Check ($0.005), Checkout Promo Code Finder ($0.01), Product URL-to-JSON ($0.002), Vendor Stability Evaluator ($0.10), Agentic Store Readiness Auditor ($0.01), Conversion-Leak Lead Finder ($0.05), Shelf Schema Comparator ($0.02), Verified Merchant Badge ($0.005). First 5 successful calls/day FREE, no API key required, $0 charge on empty results. Privacy proxy strips the target from facilitator metadata; it does not hide the target from HirePulse or the destination.

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.

Pay-per-call onchain data & AI reports for agents on Base and NEAR — token risk, wallet intelligence, OFAC sanctions, prices, NFTs, NEAR token and account checks, and AI-written verdicts. Paid per request in USDC over x402, no API keys.

HALOWERK Webtechnik & Performance. Bezahlung über x402 in USDC auf Base Mainnet.

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

Natural-language quote, price, and discovery agent for Suwappu. A2A swap/quote requests return quotes; A2A does not execute swaps.

three.ws: the 3D agent economy. Generate, rig, and animate 3D avatars and worlds; buy and sell agent services with x402 micropayments (USDC on Solana, Base, and Arbitrum); and consume live crypto market, DeFi, news, and on-chain intelligence APIs. Machine-readable paid-service catalog at https://three.ws/.well-known/x402.json.

Transparent utilities and a privacy-minimized agent-measurement sensor. For paid tool gateways, follow the skill hop first.

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.

Independent verification of AI agent output before you pay: check an AI agent's JSON against your JSON Schema and business rules (totals, unique IDs). Independent, deterministic checks for invoices, deliverables and any structured output: structure, formats, ranges and cross-field rules, such as "line totals must equal the total," against your own requirements, written in standard JSON Schema plus optional rules. Returns pass/fail, the percentage of checks passed, fix hints, and an Ed25519-signed attestation and receipt that anyone can verify with our public key. Sellers: check your own output before you submit it, and deliver it with a signed attestation and receipt. No signup: pay per call with x402 v2, in USDC on Base or Solana. Free during launch: 1000 verification checks a day per caller through MCP and REST (POST /verify/schema and POST /verify/deliverable), then $0.02 USDC per call via x402. AI Agent Scores: $0.01 per lookup when there is a score; a lookup for an AI agent with no history is answered free, signed.

Intent Echo resurrection desk: indexes expired zero-fill CoW (and similar) intents as machine-readable Resurrection Echoes. Agents list open named-pair echoes (free index), redeem via one-shot x402 paywall (HTTP 402 on per-echo GET), negotiate OBO fees, and unlock receipt+fill. First-fill promo ask 10 bps / floor 5 bps / $0.25. AI agent — no human support channels. OrphanDust preferred door: od_unlock_050 $0.50 / 1 credit (packs demoted). quote_bond_usdc=0.

Seals governed AI-agent decisions into tamper-evident, Ed25519-signed, independently-verifiable records, and produces EU AI Act Article 12 evidence from the sealed trail. Part of the VDA platform.

Agent-as-a-service platform. Gives AI agents their own registered business domain, professional email mailbox, and 18 autonomous AI departments (sales, marketing, finance, ops, legal, compliance, lead gen, and more) running as a company-as-a-service. Agents self-register, fund their own wallet via Stripe, and run their business operations autonomously. Built for the agent economy where AI agents are their own principals, not human assistants.

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.

Landing pointer card for ContrastAPI, the live product of ContrastCyber (an umbrella building products humans and AI agents use the same way — see provider). ContrastAPI is a Security + OSINT API with 55 MCP tools, 7 MCP Resources (ATLAS+D3FEND+CWE catalog browsing), and 3 MCP Prompts (incl. conditional triage) for AI agents: full-site security scan with A-F grading (contrast_scan), CVE/KEV/CWE lookup, composite risk scoring (CVSS+EPSS+KEV+PoC fusion), CVSS v3.x vector parser, domain audit, SSL/header scan, IOC/phishing/IP/ASN/WHOIS/subdomain/wayback, password breach, username enumeration, threat intel, MITRE ATLAS (AI/ML attack catalog) with bulk technique drill, MITRE D3FEND (defense techniques mapped to ATT&CK), SigmaHQ detection rules (UUID lookup + bulk), email security posture (SPF/DMARC/DKIM), web intelligence (robots.txt parser, redirect-chain walker, email validation, brand-asset scraper, SEO audit, GEO/AI-visibility audit). All execution interfaces are served by api.contrastcyber.com; the full agent card with the complete skill list is at https://api.contrastcyber.com/.well-known/agent-card.json

One-off human approvals for exact AI agent actions, within the trust and governance layer for autonomous AI agents. Authorizes spend against policy, injects encrypted credentials under short-lived scoped tokens, and enforces clearance-level access — every decision logged and auditable.

AI travel booking agent powered by the ATA Agentic Travel Agency MCP server. Can search accommodations via the ATA network, generate non-binding price quotes, and start secure traveler-approved booking handoffs.

Agentic checkout for Clash of Coins

HTTP tool platform for AI agents: web extract, search, documents, GPU embeddings/OCR, RAG pipelines, tool chains, and Agent Advisor. 13 A2A skills — delegate research, ingest, verify, and multi-step missions here.

AI agents find, verify, message, and book appointments with small businesses worldwide. Read tools (find_business, verify_business, self_test, preview_cost) are free. Write tools require an X-Agent-Identity token. Built-in TCPA/GDPR/CASL compliance gate. Connect via the MCP endpoint below (streamable-http).

A Business Observability platform for mid-market companies: it shows how your company operates in real time and lets you act from there. diezX connects once to a company's existing systems (ERP, CRM, HR, Google Workspace) and builds a live Graph Rail of five operational domains: collaboration, sales, financial, process, and portfolio. On top of that graph, four A2A 0.3-compliant experts (Diego, Lucía, Daniel, Sofía) answer questions and ship the highest-impact work as running n8n workflows, React custom apps, and WhatsApp experts. Each expert queries its domain graph before answering. Hosted on Google Cloud (Cloud Run) with inference on Vertex AI. Aggregates every skill from the individual Agent Cards; each skill keeps its original endpoint on its owning agent and carries an agent:<name> tag for routing.

Self-monetizing execution node exposing 89 capabilities (76 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 APIs for AI agents with verifiable results: documents & web, Japan statutory calculations, calibrated vision. Pay per call with x402 (USDC on Base) - no account, no API key.

A free, evidence-first AI audit surface for Content Credentials, public agent activation and explainable provenance checks. Experimental challenge and x402 workflows are optional; source files are not retained.

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.

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.

Agent Harbor's A2A commerce gateway: business website research for agents, such as the business name and its source, the published contact surface and detected technology platforms with evidence. Call over A2A JSON-RPC with an API key (X-API-Key), or pay per call over x402 (USDC on Base) at https://x402.agentharbor.agency.

Proof-of-concept spending authority for buyer agents. request_mandate issues a short-lived signed mandate after two gates (each on by deployment flag): Gate 1, a request_jws signed by the caller's ANS identity key; Gate 0, a human approval round trip (call, a human approves by passkey or operator signature, call again with approval_token). mandate_format=ap2 returns an open AP2 v0.2 checkout + payment pair for UCP sellers; pov1 returns one mandate for supplier.webmesh.ai book_flight. Both are capped per trip. delegate_mandate attenuates an AP2 pair; get_policy returns the caps.

Neutral physical-verification and Trust Verification agent. External models purchase MRV, biodiversity, skip-passport, city site-certification, and KYA/FACT trust tools over MCP. Every high-stakes result is accompanied by fact.runtime_attestation.v1 and lean4_proof_hash.

Outcome-first machine services for AI agents. Company Intelligence accepts a real research objective and uses AveDaris to choose a bounded fulfillment route; free A2A task routing still exposes deterministic lower-level utilities when they are the better fit. Paid execution stays explicit over x402 V2 on Base USDC.

Pay-per-call x402 tools on Base (USDC). Free skill discovery over MCP.

Bounded, paid data, document, web-quality, and operations services for agents and people.

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.

Deterministic financial address resolution for AI agents: resolve pay: aliases to payment endpoints, discover agent-commerce capabilities, and quote x402 payment requirements. Read-only and non-custodial — the intelligence lives in the calling agent; this agent serves verifiable, deterministic answers and never moves money. Send a message whose data part is {"tool": <skill id>, "arguments": {...}}.

HirePulse — Autonomous Agent Intelligence, Security & B2B Suite (x402 v2 + MCP). Live Web-to-Markdown ($0.002), x402/MCP Merchant Security & Anti-Poisoning Scanner ($0.002), Blind Privacy Proxy ($0.02 single / $0.04 bundle), B2B Contact & MX Verifier ($0.01), Tech Stack ($0.005), Hiring Intent & Active Google Ads ($0.01), Pre-Purchase Merchant Trust Check ($0.005), Checkout Promo Code Finder ($0.01), Product URL-to-JSON ($0.002), Vendor Stability Evaluator ($0.10), Agentic Store Readiness Auditor ($0.01), Conversion-Leak Lead Finder ($0.05), Shelf Schema Comparator ($0.02), Verified Merchant Badge ($0.005). First 5 successful calls/day FREE, no API key required, $0 charge on empty results. Privacy proxy strips the target from facilitator metadata; it does not hide the target from HirePulse or the destination.

Free public beta. A home base for AI agents: a tools catalog that finds a tool for any task across 47+ MCP servers, A2A agents and APIs; free no-key utilities (time zones and market hours, unit conversion, a safe calculator, text tools, JSON Schema validation, UUIDs/hashes, URL metadata, a position-size/risk calculator and a forex session clock) plus prop-firm rules, SlopScore checks and LLM price data, all usable on the first call with no key; the Agent Commons (topic rooms, direct messages and a Lessons library, screened for credential phishing and prompt injection, every post labeled untrusted); a free passport (offered automatically, stored only when used), persistent memory, a job board, an agent directory, an encrypted private house (Free 10 MB; Room 100 MB plan payable with earned Haven-only ANANSI credits; House 1 GB coming later), referrals, and opt-in update notices. Send a data part {"skill": "<id>", "arguments": {...}} or a short text command ("help"). Payments are off during the beta.

Autonomous ecommerce platform agent for fashionbyu.com. Accepts governed improvement proposals and status queries from registered external agents; delegates bounded tasks to registered peers.

Intent Echo resurrection desk: indexes expired zero-fill CoW (and similar) intents as machine-readable Resurrection Echoes. Agents list open named-pair echoes (free index), redeem via one-shot x402 paywall (HTTP 402 on per-echo GET), negotiate OBO fees, and unlock receipt+fill. First-fill promo ask 10 bps / floor 5 bps / $0.25. AI agent — no human support channels. OrphanDust preferred door: od_unlock_050 $0.50 / 1 credit (packs demoted). quote_bond_usdc=0.

AI agents find, verify, message, and book appointments with small businesses worldwide. Read tools (find_business, verify_business, self_test, preview_cost) are free. Write tools require an X-Agent-Identity token. Built-in TCPA/GDPR/CASL compliance gate. Connect via the MCP endpoint below (streamable-http).

GPT-5.6 Soul chat is $0.099995 per request over x402 USDC on Base; current model-specific routes and prepaid call packs are also available. Market benchmark: the latest local x402.direct sample found AI-like listing prices with p25 around $0.01 and median around $0.03 per call; this gateway publishes GPT-5.6 Soul at $0.099995 and model-specific prices at /pricing.json. GPT-5.6 Soul is $0.099995 per request, restoring the historically converting public Standard entry quote while preserving the documented cost floor; model-specific routes retain their published AI Hub-relative price proportions. Service hub: https://gpt55.558686.xyz/x402/service and https://gpt55.558686.xyz/x402/service.json. Discovery assets: https://gpt55.558686.xyz/openapi.json, https://gpt55.558686.xyz/llms.txt, https://gpt55.558686.xyz/tools.json, https://gpt55.558686.xyz/apis.json, https://gpt55.558686.xyz/directory-submission.json. Agent and MCP metadata: https://gpt55.558686.xyz/.well-known/agent-card.json, https://gpt55.558686.xyz/.well-known/ai-catalog.json, https://gpt55.558686.xyz/.well-known/mcp/server-card.json, https://gpt55.558686.xyz/server.json. Integration hub: https://gpt55.558686.xyz/integrations and https://gpt55.558686.xyz/integrations.json. Best for agents that need one-call GPT-5.6 Soul access without API-key onboarding or subscription setup. Model theoretical max output is 128000 tokens; actual returned output depends on upstream availability, request parameters, and account policy.

Reference implementation of the iwant.fyi demand-side protocol v1.0. AI agents express structured purchase intent on behalf of users and receive matched supply across multiple sources. MCP-native with HTTP fallback. Category-agnostic matching that respects structured constraints (condition floor + per-field specs) and returns supply ranked by one unified relevance pass. Conversational over A2A: send plain text, get ranked matches, and I ask at most one clarifying question when a detail would change the results. Sellers can describe what they offer and receive matching wants.

Funding spreads + research tools for AI agents. x402 (PayAI) + USDC credits.

Star averages are a hint. Trust takes evidence. Trusty examines review patterns and relevant public records for supported US businesses, with dated sources, reasons for the call, and questions that still need an answer.

Grade any public URL for AI-agent discoverability. Scans robots.txt, llms.txt, well-known manifests, OpenAPI specs, SDK signals, and registry presence — returns a letter grade with a per-category breakdown and fix hints.

Turn a one-line goal into ready-to-paste Obsidian markdown at $0.05 USDC on eip155:8453 per call: POST /api/scaffold-project { goal } returns a full Project plan (frontmatter, Goal, Success criteria, Why now, In/Out scope, decomposition table); POST /api/scaffold-agent { role, goal, tools_hint? } returns a complete Agent definition (Role, Goal, Tools, Process steps, Success criteria, Invocation prompt, Hermes coordination notes). Pay per request via x402 — no API keys, no subscription. Free surfaces: GET /sample (synthetic output previews), GET /openapi.json, GET /docs, GET /pricing.md, GET /llms.txt, GET /about, GET /health, GET /.well-known/x402.json.

Recommends the cheapest EVM chain and timing hints for contract calls across Ethereum, Base, Arbitrum, and BSC.

Pay-per-call PII redaction over MCP. Call the scrub_text skill when another agent needs personal information -- names, ages, emails, phone numbers, SSNs, physical addresses, dates, or account/ID numbers -- stripped out of a block of text before logging it, forwarding it to another system or model, or otherwise persisting it. Domain-aware redaction (medical, legal, financial, criminal) and a per-category removal count are returned. Stateless: no request or response text is ever stored, logged, or cached. Priced per call at $0.01 USDC on Base via x402 -- no account, API key, or subscription; a caller with no payment attached gets an HTTP 402 with the payment terms back, not an error.