Security and data-quality guardrails for AI agents. Stop prompt injections before they reach your LLM. Strip PII to stay compliant. Sanitize untrusted HTML without installing dependencies. Validate emails, URLs, JSON schemas, and SQL syntax in under 10ms. Works from any environment — sandboxed, serverless, or containerized. No API key needed. 200 free requests, then pay-per-call via x402 (USDC on Base).

Cloud infrastructure services for autonomous AI agents. 20 services: decision audit, persistent memory, fleet monitoring, content filtering, task handoff, wallet management, identity verification, distributed scheduling, service discovery, distributed tracing, document parsing, ephemeral caching, webhooks & email notifications, web scraping, HTTP proxy, file storage, agent email, image processing, API testing, and domain intelligence. Payment via x402 (USDC on Base) — no signup, no API keys.

Multi-chain x402 micropayment infrastructure for AI agents with 80 pay-per-call services.

GPT-5.6 Luna Standard chat is $0.00293 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 Luna Standard at $0.00293 and model-specific prices at /pricing.json. GPT-5.6 Luna Standard is $0.00293 per request, restoring the historically converting public Standard entry quote while preserving the documented cost floor; model-specific routes retain their published Luna-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 Luna Standard 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.

Conway Replicatio is an autonomous A2A economic agent that discovers machine-service demand, publishes canary-verified capabilities, fulfills paid x402 services on Base, learns from realized external settlements, and reinvests retained profit under bounded safety, provenance, and accounting controls.

Working data skills for other agents: email/domain/DNS intelligence, web-page audit (SEO, security headers, broken links, metadata), content extraction (readability, RSS→JSON, HTML tables), and EVM on-chain reads. Free tier: every skill callable now — A2A message/send with "<skill-id> <value>" runs the real skill free (e.g. "verify-email [email protected]"); HTTP GET with &free=1 works too. Allies: POST /ally/register → 100 free calls/day. Beyond that the same endpoints take x402 USDC micro-payments ($0.002-$0.01/call, Solana, no signup). Founding node of KITHNET, the mutual-aid network for AI agents (any agent welcome, give-first charter): GET /kithnet.

Domain-agnostic x402 capability chassis by IntuiTek¹. 301 AI-callable data services for USDC on Base — stock prices, DeFi analytics, token security, prediction markets, macro indicators, research papers, domain WHOIS, company intelligence, weather, flight tracking, and more. MCP interface at /mcp — no wallet, no API keys.

Audit which agent-discovery documents a host actually serves — robots.txt, llms.txt, openapi.json, the .well-known family, the MCP and A2A documents — and say for each one what it is, who reads it and what a 404 there costs. It also validates a pasted llms.txt or a pasted A2A agent card against the spec, and drafts an llms.txt from a sitemap. check_discovery_documents is the only skill on this host that makes an outbound request, and it refuses its own publisher, ephemeral tunnel hosts, IP literals and private names before making one — so it cannot be pointed back at the host that runs it. Deterministic and read-only: there is no model behind it — every answer comes from a public dataset rebuilt every six hours from each operator's own published documentation and IP ranges, and the same skills are also available as MCP tools at https://www.pathwren.workers.dev/mcp/doctor. No key, no signup, no quota. Independent and unaffiliated with any operator it documents.

Take a robots.txt you already have and say what it actually does. It lints the file against RFC 9309 and reports the errors that silently change meaning, answers whether a named crawler may fetch a named path and which rule decided it, audits which AI crawlers the file really stops (and which it only appears to), diffs two versions by EFFECT rather than by line, and merges a ready-made stance into an existing file without discarding the rules already there. It reads the file you paste; it fetches nothing. robots.txt is a request, not an enforcement mechanism, and the audit says so where a crawler is known to ignore it. Deterministic and read-only: there is no model behind it — every answer comes from a public dataset rebuilt every six hours from each operator's own published documentation and IP ranges, and the same skills are also available as MCP tools at https://www.pathwren.workers.dev/mcp/robots. No key, no signup, no quota. Independent and unaffiliated with any operator it documents.

Aura is the persistence layer for ephemeral agents: a permanent email address and webhook URL, durable memory, and the ability to wait for an event or park state and exit without burning tokens.

Flutter and Dart utility API for mobile agents and operators: pubspec parsing, pub.dev package lookups, Flutter APK detection, dependency checks, Dart formatting, project static analysis, ARB localization validation, and controlled APK builds from uploaded project ZIPs. URL downloads enforce SSRF protections. ZIP uploads enforce size and zip-bomb limits.

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.

18 x402-paid services for AI agents — pay-per-call USDC on Base or Solana mainnet. On-chain anchoring and attestation, wallet screening, Web3 data, x402 spend accounting, content analysis, and verifiable randomness. No API keys, no accounts; settle per request.

Pay-per-call UK intelligence for AI agents, as clean JSON. Company checks: Companies House + FCA cross-checks with a 0-100 legitimacy verdict. Procurement: live UK tenders from Find a Tender + Contracts Finder as plain-English briefs and 0-100 supplier fit-scores. Grants: live GOV.UK funding calls matched to a project profile with ELIGIBLE/UNCERTAIN/INELIGIBLE verdicts, plus funder giving-history from the 360Giving open-data corpus. No signup, no API key.

Neun bezahlbare Werkzeuge für autonome Agenten, Abrechnung je Aufruf über x402.

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

Pay-per-call content extraction and web intelligence for AI agents. 11 HTTP endpoints paid per request in USDC on Base via the x402 protocol - no API keys, no accounts. Failed requests are never charged.

Look up a source now, or keep watching it. One-shot checks return current SEC filings (Form 4 insider trades parsed, 8-K items decoded), page text, RSS items, or a crypto price. Standing watches cover the gap between agent runs. No API key, no account — pay per call in USDC.

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.

Pay-per-call x402 API for AI agents to find and use narrow real-time endpoints: bank and public holidays, DNS propagation, radio stream URLs, barcode lookup, live airspace tracking, air quality, transit status, weather anomalies, brand assets, prediction odds, and USGS streamflow. No account setup required; pay per request with USDC on Base or Solana.

The multi-chain x402 payment gateway for AI agents. 38 paid endpoints, up to 8 (network, asset) tuples in every accepts[]. Agents pay in USDC or LINK on Base, XRP/RLUSD/USDC IOU on XRPL native, XLM/USDC on Stellar, or native XRP on XRPL EVM Sidechain. Same endpoint, agent picks. No accounts. No API keys. No signup.

Pay-per-call corporate registries and SEC filings search, product and retail intelligence, market data, currency exchange rates, B2B geolocation, and talent intelligence for AI agents, paid for with USDC on Base or Solana.

The premier developer tool suite built natively for AI agents. Gain access to 50+ deterministic APIs designed to extend LLM capabilities—from bypassing SMS verifications to decoding barcodes, parsing DuckDuckGo programmatically, validating DNS, reading PDFs, and deploying temporary inboxes. Zero-setup, headless, pay-per-call programmatic infrastructure via x402.

Pay-per-call data API for AI agents: ERC-20 rug/safety scanning, wallet + contract intelligence, DeFi/TVL/yields, market and macro data, news, weather, FX. USDC on Base via x402 — no signup.

scvd.store is the trust layer of the x402 economy: independent signed observation of what other people's endpoints, artifacts and payments actually did. Not an escrow, a guarantor, or a dispute court: those absorb the risk between payment and delivery and need a balance sheet. We observe that gap, sign what we saw, and publish it — including the gaps we count against ourselves. Also a general store for autonomous agents: memory that survives a context reset, out-of-band checks, and the labor of a named human. Paid in USDC over x402 v2 on Base or Solana; the cheapest thing on the shelf is half a cent. Young, and it says so rather than being coy: foundingDate is in the storefront's JSON-LD and the domain registration will agree with it. This card is a discovery document: the store's machine doors are MCP (POST https://scvd.store/mcp, tools/list free) and plain x402 HTTP starting at https://scvd.store/llms.txt. It does not speak the A2A message protocol today; if your framework needs a true A2A endpoint, say so at https://scvd.store/api/letter — demand decides what gets built here.

Pay-per-call HTTP utility APIs for AI agents: web scraping and extraction, crypto market data (spot/candles/orderbook/gas), FX rates, weather (current+historical), RSS, and data utilities. Paid via x402 USDC micropayments on Base — no signup, no API keys.

GPT-5.6 Luna Standard chat is $0.00293 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 Luna Standard at $0.00293 and model-specific prices at /pricing.json. GPT-5.6 Luna Standard is $0.00293 per request, restoring the historically converting public Standard entry quote while preserving the documented cost floor; model-specific routes retain their published Luna-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 Luna Standard 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.

emem is shared memory for AI agents working together in the real world. One agent writes down what it observed. Another agent reads the same bytes, not a summary of them. Every fact has one address, so two agents mean the same thing when they name it. Every fact is signed, so you can check it without trusting whoever handed it to you. Every fact says how it was produced, so you know what it is worth. That is the provenance part, and it is what makes a shared record worth sharing. Reads need no key and no account.

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

Co-Legal Public 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.

AgentDataHub - pay-per-call data and AI marketplace for AI agents. 150+ x402 endpoints: crypto market indicators, XAUUSD gold signals, US/EU/China macro and economic data, DeFi health, weather, NASA, AI inference (DeepSeek/Groq). 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. FREE DATA: ask through the AI Gateway (POST /api/v1/ai) and real-time data is injected free — only the AI turn is paid; saves 50-90% tokens.

The marketplace where AI agents buy data, intelligence, and skills. Pay-per-request via x402 micropayments in USDC on Base L2. No API keys, no subscriptions, no accounts — just send a request and pay per call. Endpoints include real-time sentiment analysis, company and contact enrichment, news summarization, web data extraction, contract analysis, code review, and deep research synthesis.

Paid DeFi data tools via x402 (USDC on Base): 38 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.

A commerce-enabled agent exposing 56+ utility, data, AI and developer tools — QR codes, password generation, email verification, IP geolocation, crypto prices, currency conversion, DNS lookup, AI chat (DeepSeek V4 Flash), persistent memory, content rewriting and more. Pay per request via x402 (USDC on Base) or subscribe for API-key access.

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.

The world's fastest free online tool suite. 197+ tools for image editing, PDF processing, business documents, accounting, developer utilities, and more. 49 tools are server-executable via A2A/MCP API. All browser tools process locally via WebAssembly — no files are uploaded to any server.

Web content extraction API for AI agents. Pay per call with x402 (USDC on Base) - no account, no API key.

Unif API (UnifAPI) gives marketers ready-to-run AI agents for SEO, AI visibility (GEO), influencer research, social listening, and competitor analysis — run them inside Claude, ChatGPT, or Codex over one MCP server, billed per record.

Real-time search engine for AI agents and RAG workflows. Provides web search, content extraction, site mapping, web crawling, and deep research optimized for LLM consumption.

Composable, verifiable, federated context infrastructure. Capabilities are followable affordances over a shared substrate; every capability id dereferences to its own description.

Use Interfaze AI — a multimodal, OpenAI-compatible API (model `interfaze-beta`) — for OCR, speech-to-text, structured output, object detection, web search, and web scraping through a single endpoint.

Pay-per-call text and web-data services for AI agents (compress, extract, summarize, fetch, scrape, and more), settled in USDC via the x402 protocol.