PostalForm helps AI agents create reviewable physical-mail drafts and, when explicitly authorized, pay for print-and-mail orders through MCP, hosted checkout, MPP, or x402.

Production trust infrastructure for autonomous AI agents. W3C DIDs, Verifiable Credentials, Agent Authorization Envelopes (AAE), on-chain anchored on Base L2. Reference implementation of the Trust Registry Binding for A2A v1.0.

The verification layer for autonomous agents: a neutral, model-agnostic verdict before an irreversible action (/review — capital-scale-aware, the gate our own live trading bot passes on every entry), 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.

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.

GPT-5.6 Luna Standard chat is $0.019999 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 $0.019999 and model-specific prices at /pricing.json. GPT-5.6 Luna Standard is $0.019999 per request, the rounded six-decimal geometric mean of the previous public Standard and Luna quotes; 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.

Convert between common document and data formats in one API for content and data agents: Markdown to HTML, HTML to Markdown, HTML to clean plain text (scripts/styles stripped, entities decoded), CSV to JSON (with or without header row), JSON array to CSV, YAML to JSON, and JSON to YAML. Pure in-process conversion with no external calls and no shell access.

Independent verification of South African ZARONIA-linked FRN and money-market coupons against the SARB Compounded ZARONIA Index, with full workings and an audit verdict at 0.05bp tolerance.

REST API for BCH full node, Fulcrum, and SLP data; access via x402 USDC on Base or documented bypasses.

AurelianFlo is a pay-per-call API for OFAC wallet screening, crypto wallet sanctions checks, exposure forecasts, review queue optimization, enhanced due diligence memos, and audit-ready document output (PDF, DOCX, XLSX). Built for compliance teams, fintech operators, treasury workflows, and AI agents. No API keys. Paid in USDC via x402.

Semantic search across 10 pre-indexed developer documentation platforms — Cloudflare, Stripe, Anthropic, OpenAI, Next.js, and more.

Paid HTTP+JSON x402 service for listing quality, buyer-agent skip reasons, and x402 discoverability audits.

High-quality, x402-native, LLM-optimized APIs. Each is pay-per-call in USDC; GET any API's base path for a free help document, and GET /<api>/sample for a FREE real cached response so you can judge the data before paying.

EmblemAI is open-source crypto infrastructure for both end users and AI agents. 200+ tools across 7 blockchains (Solana, Ethereum, Base, BSC, Polygon, Hedera, Bitcoin) for swaps, conditional orders, DeFi, NFTs, cross-chain bridges, and market intelligence. x402 payment rails, A2A and MCP protocol support, and a CLI installable via npm i -g @emblemvault/agentwallet.

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.

Pre-indexed proprietary documentation for autonomous agents. Semantic search across platform docs, paid via x402 micropayments.

15 utility APIs for AI agents -- fact verification, intent security, reversibility intelligence, baseline reality checks, situational awareness, documentation search, conversion, validation, weather, time, hashing, text processing, math, geocoding, and DNS

Pay-per-call verification and data APIs for autonomous agents: check packages, crawl permissions, sanctions lists, and products before acting. x402 v2, USDC on Base. No API keys, no signup — payment is the authentication.

MCP server for the Hive Compute Grid. 11 tools wrap a 15-agent fleet across 6 driver types: cross-pool auction (real io.net/Akash/Render adapters), workload decomposition, verification fleet ($0.001/proof), capacity listener, QVAC mesh, settlement reporting. Real rails. New agents: first call free. Loyalty: every 6th paid call is free. Pay in USDC on Base L2.

Cross-model evidence pipeline for AI agents. Specialized extraction and verification models deliver source-grounded facts from financial filings and contracts — up to 3.8x cheaper than calling frontier models directly. Public paid workflows: analyze_public_filing, review_contract_risks, and analyze_document. Pay-per-call via x402 USDC with dynamic pricing from $0.03 to a $79 ceiling.

Domain-agnostic x402 capability chassis by IntuiTek¹. 300 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.

The multi-chain x402 payment gateway for AI agents. 47 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 text and web-data services for AI agents (compress, extract, summarize, fetch, scrape, and more), settled in USDC via the x402 protocol.

Deterministic, evidence-bound launch, x402 preflight, and exact-token Base NFT audit services operated by Aura under Helionix Labs.

Stablecoin-funded real-world payments for autonomous agents.

The open observatory of global internet censorship — measured, predicted, and machine-readable. 2.2B+ network measurements across 130 countries: live censorship rankings, citable incidents with evidence permalinks, and KeepItOn-validated shutdown-risk forecasts. Voidly Pay (off-chain agent credit ledger + x402) and Relay (E2E encrypted agent-to-agent messaging) are sibling agent-economy rails built on top.

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, BSC, and X Layer); 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.

Cryptocurrency research and scoring platform. TVR's scoring model evaluates cryptocurrencies using 8 fundamental metrics rooted in Sound Value principles to produce TVR Scores (0-100). TVR's valuation formula produces TVR Estimated Values (fair value estimates) and Valuation Categories (Undervalued, Fair Value, Overvalued). All outputs are model-derived assessments for informational and educational purposes only.

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.

17 products and 50+ MCP tools (2 MCPs) built by solo founder Brennan Zambo. Products are standalone websites. MCP tools are callable APIs (includes ZAMBOT, ZAMBRO, ProvibeCode, and more). Universal agent router, swarm strategy, swarm debate, drift detection, spark chains, code audits, lead gen, verified identity, and more. Zero auth, zero signup for the free tier. Agent-payable via x402 (1.49 USDC/24h on Base).

Vehicle Intelligence for AI agents. Pay per call with x402 (USDC on Base) to decode any 17-char VIN with its original factory new-vehicle warranty terms folded in ($0.01), read MERGED US (NHTSA) + Canada (Transport Canada) recalls with the full decoded VIN folded in ($0.01), and get LLM-clustered known-issue reports that bundle a reliability-aggregates block and the full decode (every issue cites verified ODI complaint numbers; $0.05), plus itemized used-car closing costs for all of Canada + all 50 US states & DC via /v1/purchase-costs?country=CA|US ($0.02). FREE /v1/sample/* endpoints return every response shape for one fixed sample vehicle (2013 Ford F-150, VIN 1FTFW1ET5DFC10312) so you can try before you pay. Every JSON object response carries a legal `disclaimer` field. Informational data only — not professional/purchase advice, and NOT a vehicle-history report (no liens/accidents/odometer). Contains information licensed under the Open Government Licence – Canada.

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.

Pay-per-call API for French & European company data. France in depth (INSEE Sirene / INPI RNE open data — 25 datasets) plus European search & profiles (Belgium, UK, Norway, Estonia, Latvia) and worldwide entities via LEI/GLEIF. AI agents pay per request in USDC on Base via the x402 protocol — no account, no API key.

Agentic Gateway — Foundational Platform for Auditable Production AI. Search and execute across OpenAPI sources with audit, cache, optional vault memory, native Stripe + x402 + MPP + AP2 + ACP payments (plus PayPal Orders and Adyen Checkout), and defense-in-depth controls.

GPT-5.6 Luna Standard chat is $0.019999 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 $0.019999 and model-specific prices at /pricing.json. GPT-5.6 Luna Standard is $0.019999 per request, the rounded six-decimal geometric mean of the previous public Standard and Luna quotes; 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.

AstraNL is the Proof-of-Reality Protocol for autonomous agents. Agents bring goals, budgets and plans; AstraNL finds where those goals can safely enter reality, routes them through verified providers, materials, documents, machines and approvals, then returns proof of real-world impact: paid task, KvK-verified provider, HMAC-signed attestation, escrow-released completion. 1% coordination fee, 99% to provider.

MCP server for AI agents providing web scraping, screenshots, structured data extraction, code review, content generation, and sentiment analysis. Pay per call with USDC via x402.

The world's fastest free online tool suite. 196+ 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.

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.

x402 M2M payment gateway — pay-per-call agent APIs: on-chain/token intel, DEX price & liquidity, market news + sentiment, SEC filings, web scraping, token compression, semantic caching.

AI-synthesized insurance intelligence API. Auto coverage analysis, life insurance needs calculator (DIME method), homeowners gap finder, annual coverage review, renters insurance guidance, global health/medical insurance advisor, business insurance planner, claim should-I-file analysis, disability/income-protection calculator, life-event insurance checklist, rate/premium optimizer, and umbrella/excess-liability calculator. Global: country-aware norms and benchmark anchors. Returns structured JSON. Requires x402 micropayment (USDC on Base mainnet).

Live data marketplace selling US public record and scientific data to AI agents. 4.8 million+ records across 76 sources: cyber vulnerabilities, sanctions screening, federal court opinions, SEC filings, scholarly research, healthcare, FDA recalls, government spending, economic indicators, regulations, environment, and consumer safety. Every record carries a provenance URL to its authoritative primary source plus a cryptographic signature. Purchases settle instantly in USDC on Base via the x402 payment protocol. Also reachable over MCP with 15 tools including a free catalog.

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.

A reference A2A agent demonstrating the AgentCard discovery path declared by the agents.txt standard. Knows the spec, can describe directives, validate files, and point clients at the live MCP tools served by this site.

Global elder care intelligence API — 14 endpoints covering Medicare/pension guidance, care facility evaluation (US + UK + Canada + Australia), medication safety using FDA Beers Criteria, benefits discovery (SSI, Medicaid, VA Aid & Attendance, SNAP, LIHEAP, property tax relief), international state pension intelligence (UK, Canada, Australia, Germany, India, Japan), cognitive decline staging, elder law documents, post-loss estate guidance, and caregiver support. Returns structured JSON. Requires x402 micropayment (USDC on Base mainnet). All endpoints support any language via ?lang= parameter. U

AI-synthesized real estate intelligence API covering any country. Mortgage/remortgage analysis, true affordability modeling, rent vs. buy decisions, refinance opportunity, hyperlocal market conditions, and rental-market intelligence. Location + optional country params; jurisdiction-aware for US/UK/CA/AU/DE/IN with honest fallback elsewhere. Returns structured JSON. Requires x402 micropayment (USDC on Base mainnet).

The universal AI tutor and exam prep API. Every subject. Every exam. Every certification. Every language. Covers all K-12 subjects, all college courses, all professional licensing exams (NCLEX, Bar, CPA, LSAT, MCAT, Series 3/7, USMLE, CFA, CFP, real estate, electrician licensing, CDL, FAA, air traffic control, HVAC, plumbing, and any other credential worldwide), all continuing education requirements in any profession, homeschool families in any US state or country, and college admissions essay review. Pay-per-query via x402 micropayments on Base. All endpoints support ?lang= for native respons. NEW: financial-aid appeal engine — deterministic HEA §479A professional-judgment / dependency-override screening with statute-level citations ($0.50) and citation-backed appeal letters to the aid office ($5.00); free per-circumstance explainers at /appeals/. ALSO NEW: student-loan fix engine — federal discharge (false certification/closed school/identity theft) + PSLF reconsideration/buyback + California AB 376 servicer demand letters with statutory damages floors ($0.50 screen / $5.00 document); free explainers at /loan-fixes/.

Hospital price transparency intelligence API. Find lowest-cost providers for any procedure, benchmark against Medicare, calculate out-of-pocket costs, get bill negotiation scripts, compare dental and cosmetic pricing. Returns structured JSON. Requires x402 micropayment (USDC on Base mainnet).

Machine-payable file type detection and asynchronous file conversion service for AI agents. Use the OpenAPI contract for invocation. Paid routes support x402 exact payments and MPP Tempo charge.

AI agent and infrastructure that answers verified questions about the Celo blockchain ecosystem, contracts, MiniPay, stablecoins, DeFi, staking, governance, and developer tooling. Other agents and dApps can query its knowledge via A2A and the SDK.

Paid page freshness API for agents that monitor docs, release notes, pricing, and policy pages

AI x Bitcoin platform. Register your agent, message other agents, and earn satoshis. Only one action costs money: sending a new message (100 satoshis via x402 sBTC). Everything else is free — registration, reading inbox, heartbeat, replying.

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). Note: micropayment billing (x402/USDC) is coming soon — not yet active.

Payment-gated x402 endpoints for Sagitta AAA portfolio intelligence and SCE execution preflight. Includes allocation, market regime, policy envelope, asset scoring, rebalance, continuity mode, case relevance, and doctrine-based risk evaluation for autonomous agents.

Charter-clean web toolkit for agents: give it one publicly reachable URL, get back clean, LLM-ready markdown (free), or a screenshot/PDF via x402 ($1+). Honors robots.txt, identifies honestly, read-only, never bypasses anti-bot/CAPTCHA/paywalls. No account, no API key.

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.

The open observatory of global internet censorship — measured, predicted, and machine-readable. 2.2B+ network measurements across 130 countries: live censorship rankings, citable incidents with evidence permalinks, and KeepItOn-validated shutdown-risk forecasts. Voidly Pay (off-chain agent credit ledger + x402) and Relay (E2E encrypted agent-to-agent messaging) are sibling agent-economy rails built on top.

Production-grade blockchain infrastructure for AI agents. 76 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.

The YoMo Documentation, a serverless LLM function calling framework, enabling developers to build and deploy ai agents with MCP fast and easily.

Terminal-first A2A client docs for the Handler CLI, TUI, MCP server, and server authentication setup.

A2A intelligence endpoint for IT hardware parts. FLIS lookup, PN normalization, cross-references, pricing intelligence for 10.9M+ parts.