Paid x402 API for builders launching agent-facing services: $0.001 listing scores, $0.01 full roasts, and a $0.01 Bazaar discovery audit for stale pricing, direct 402 metadata, and search visibility on Base USDC.

Pay-per-call gateway for AI agents: Google web search ($0.01), Exa neural search ($0.012), Firecrawl URL→markdown scraping ($0.015), and LLM inference ($0.005). USDC on Base via the Coinbase CDP facilitator — no accounts, no API keys, no subscriptions. MCP server included so any MCP agent can use it with just a funded wallet. ([Catalog](https://enrich-gate.vercel.app/)) ([GitHub](https://github.com/enrichgateagent-png/x402-agents))

Pay-per-call FDA drug safety profiles for AI agents: label highlights (boxed warning, contraindications, interactions), pregnancy/pediatric/geriatric flags, top adverse-event signals, recent recalls, and shortage & marketing/discontinued status — all in one call. RxNorm-normalized drug-name resolution with a match confidence score. $0.04 USDC on Base via Coinbase CDP facilitator, no API key, no account. Data: openFDA (CC0).

Resolve a company name to its canonical Legal Entity Identifier (LEI) for AI agents: legal name, status, jurisdiction, address, registration status, and corporate hierarchy (direct/ultimate parent + children) in one call, with a fuzzy-match confidence score and disambiguation candidates. $0.03 USDC on Base via Coinbase CDP facilitator, no API key, no account. Data: GLEIF (CC0).

Screen a person, company, or crypto wallet address against the OFAC SDN list (US Treasury) and the UN Security Council Consolidated List in one call: matches with source list, sanction programs, alias matched, and match type (exact/token/address), plus list-freshness metadata. Covers 20k+ sanctioned entities and 400+ sanctioned wallet addresses across chains (ETH, BTC, TRX, XMR...). $0.02 USDC on Base via Coinbase CDP facilitator, no API key, no account. Data: US Treasury + UN (public government data).

Track US Regulation Crowdfunding (Form C) startup raises for AI agents: query live and historical offerings by issuer CIK, industry (SIC), state, security type, minimum size, or recency — returns parsed deal terms (amount sought, max, raised-so-far, deadline, funding portal, issuer financials) with honest open/closed/unknown statuses and index-freshness metadata. 1,200+ offerings indexed from SEC EDGAR (public domain). $0.02 USDC on Base via Coinbase CDP facilitator, no API key, no account.

17 agent-native pay-per-call endpoints: blockchain queries (balance, gas, chain-id, code, receipts, token balances, token security, wallet info), crypto funding rates & prices, DeFi yields, domain enrichment, tech-risk scoring, prediction market data, MCP scanning. $0.001–$0.05 USDC on Base. ([OpenAPI](https://x402-data-api.sigrunner.workers.dev/openapi.json) | [Discovery](https://x402-data-api.sigrunner.workers.dev/.well-known/x402))

Network forensics and adversarial verification for AI agents on Base mainnet. `/v2/forensics` ($0.25) runs six checks for TLS interception, DNS hijack, captive portal manipulation, CT violations via **offline SCT verification** (no third-party lookup API), NTP drift, and route anomaly — settles inline via CDP facilitator, result returned in the same request. Also `/v1/verify` ($0.50–$4.00, three-critic adversarial chain) and `/v1/synthesize` ($2.00–$5.00, multi-source synthesis). Self-hosted 35B inference, no third-party model API. Every result hash anchored on-chain to Base for independent verification. ([.well-known/x402.json](https://api.mcx-ventures.com/.well-known/x402.json) | [llms.txt](https://api.mcx-ventures.com/llms.txt) | [OpenAPI](https://api.mcx-ventures.com/openapi.json) | [x402-list](https://x402-list.com/services/aegis))

20 utility tools for AI agents via x402 USDC micropayments on Base. Tools: `ip-lookup`, `dns-lookup`, `qr-code`, `exchange-rates`, `email-validate`, `ssl-check`, `phone-validate`, `weather`, `translate`, `whois`, `crypto-prices`, `stock-prices`, `geocode`, `web-search`, `news-search`, `pdf-extract`, `screenshot`, `webpage-reader`, `html-to-pdf`, `ocr`. $0.001–$0.008 USDC per call. No API keys, no signup. Auto-discovery: [/.well-known/agent-services.json](https://agentsvc.io/.well-known/agent-services.json) | [Catalog](https://agentsvc.io/api/v1/services) | [OpenAPI](https://agentsvc.io/api/openapi.json) | [MCP Server](https://agentsvc.io/mcp-server.mjs) | ([GitHub](https://github.com/jakobautomation/agentsvc-mcp))

75 pay-per-call intelligence APIs (930+ endpoints) for AI agents under one federated catalog: token-safety verdicts across 8 chains including Robinhood Chain (memecoin + EVM rug/honeypot analysis), macro & FRED-grade economic primitives, geopolitical risk, clinical-trials intel, US government spending, stablecoin/RWA monitors, sports data, prediction markets, immigration/tax/legal doc-prep, and more. $0.001–$2.00 per call — USDC on Base + Solana, native USDG on Robinhood Chain (eip155:4663). CDP-facilitated settlement, per-repo `/.well-known/x402.json` discovery on all 70+ hosts, no API keys or signup. ([Hub & catalog](https://pulsenetwork.theaslangroupllc.com)) ([llms.txt](https://pulsenetwork.theaslangroupllc.com/llms.txt)) ([OpenAPI](https://pulsenetwork.theaslangroupllc.com/openapi.json)) ([MCP](https://pulsenetwork.theaslangroupllc.com/mcp))

39 x402-gated AI data services on Base: token forensics (TokenScope), smart contract audits (RattlerAI/CottonmouthAI/CopperheadAI), weather consensus, oil & gas (CrownBlock), on-chain intel (ChainScout), macroeconomics (MacroPulse), real estate, commodities, stablecoin risk, and more. $0.02-$2.00 USDC per call. No API keys. MCP server at mcp.lonestaroracle.xyz (38 tools, xyz.lonestaroracle/mcp-server v1.1.0). ([Discovery](https://token.lonestaroracle.xyz/.well-known/x402.json) | [MCP](https://mcp.lonestaroracle.xyz) | [Status](https://status.lonestaroracle.xyz))

Monero & Zcash payment watching for AI agents: hand over a **view key** (read-only) and a webhook URL, get an HMAC-signed POST for every inbound XMR/ZEC payment — watches run on the operator's own full nodes, credit-metered at $0.02/day + $0.005/event, topped up via x402 USDC **or natively in XMR/ZEC**. Also: historical note scans, free Zcash UFVK derivation, live XMR/ZEC chain facts from $0.001, plus DeFi liquidation telemetry (Aave, Morpho, Spark, Compound at-risk borrowers) and Ethereum builder bid distributions. Settles via Coinbase CDP with Bazaar discovery on every route. REST + MCP, no API keys. ([Discovery](https://api.seneschal.space/.well-known/x402)) ([MCP Server](https://mcp.seneschal.space)) ([GitHub](https://github.com/Rotwang9000/seneschal-data-api))

Production x402 API on Base that validates exact-token OpenSea listing and offer structure using token-specific market evidence. Includes [OpenAPI](https://aura-revenue.helionixlabs.com/x402/openapi.json) and [agent instructions](https://aura-revenue.helionixlabs.com/x402/llms.txt).

Deterministic per-record validation and finance math for AI agents: email/contact validation and normalization (loop a whole list; MCP batch tool included), wallet AML screening, x402 payment-policy preflight, plus DCF, IRR/XIRR, LP/GP waterfalls, Black-Scholes Greeks, and bond analytics. Same input, same answer, per-rule evidence, no data feed. $0.02-$2.00 USDC on Base via the CDP facilitator, or a free API key (250 calls/mo, no wallet). ([MCP](https://hermesplant.com/mcp)) ([OpenAPI](https://hermesplant.com/openapi.json)) ([x402 manifest](https://hermesplant.com/.well-known/x402)) ([Agent Card](https://hermesplant.com/.well-known/agent.json)) ([llms.txt](https://hermesplant.com/llms.txt))

Independent verification of agent work products — citation-support checks and data/schema validation returning wallet-signed attestations (EIP-191) — plus cited coding research that ships pre-verified with a signed attestation. $0.10/research call, $0.25/verification, USDC on Base mainnet via CDP facilitator. Free per-wallet quotas, free receipt-verification endpoint, Bazaar discovery extension, no API keys or signup. ([llms.txt](https://agent-business.142.93.127.153.sslip.io/llms.txt)) ([OpenAPI](https://agent-business.142.93.127.153.sslip.io/openapi.json)) ([Discovery](https://agent-business.142.93.127.153.sslip.io/.well-known/x402))

Send a monthly OpenAI API bill, get back the flat ChatGPT/Codex subscription tier that absorbs it through the ProxyLLM gateway: exact new total, savings, live model catalog, and machine-readable agent signup steps (email OTP, no browser). $0.005 USDC on Base via Coinbase CDP facilitator, no API keys. ([OpenAPI](https://proxyllm.ai/openapi.json) | [auth.md](https://proxyllm.ai/auth.md) | [llms.txt](https://proxyllm.ai/llms.txt))

Signed, fail-closed trust & verification primitives for agent-to-agent commerce. `agent-clearance` is the counterparty credit-check before one agent pays another: OFAC SDN + live on-chain wallet screen → CLEAR/REVIEW/BLOCK. Plus `claim-verdict` (grade any claim vs external ground truth), `grade-strategy` (REAL_EDGE/REGIME_LUCK/NEGATIVE_EV), `screen-entity` (OFAC SDN), `insider-conviction`/`smart-money` (proprietary EDGAR scoring), and `distress-score` (single-ticker distress vs a backtested modified-Altman-Z model). Every response Ed25519-signed and independently verifiable, no account. Free tiers, then $0.02–$0.75 x402 USDC on Base via a self-hosted facilitator (no CDP dependency). Paid MCP server (edge-gate) listed in the official MCP Registry. ([llms.txt](https://nolawealthfinancial.com/llms.txt)) ([agent.json](https://nolawealthfinancial.com/.well-known/agent.json)) ([OpenAPI](https://nolawealthfinancial.com/openapi.json)) ([MCP Registry](https://registry.modelcontextprotocol.io/v0/servers?search=stillos-edge-gate))

CFTC Commitment of Traders positioning across all 438 futures markets (disaggregated + TFF): trader-category breakdowns, week-over-week changes, 52-week COT index, crowding-extremes screener, spec-flow rankings, and sector views. Live previews in every 402 response. $0.05–$1.00 USDC per call on Base via CDP facilitator, no API keys. Updated every Friday within hours of CFTC release. ([Discovery](https://api.nimatron.com/.well-known/x402)) ([llms.txt](https://api.nimatron.com/llms.txt)) ([Catalog](https://api.nimatron.com/free/cot/catalog))

Experimental institutional memory and knowledge graph platform exposing x402 discovery metadata, payment OpenAPI docs, MCP, and A2A surfaces for Base USDC agent-commerce workflows. ([x402 discovery](https://forgecascade.org/.well-known/x402) | [Payment OpenAPI](https://forgecascade.org/openapi.payments.json) | [Agent card](https://forgecascade.org/.well-known/agent-card.json))

YouTube data APIs for AI agents, paid in USDC on Base. Two endpoints live: `POST /api/agents/transcribe` ($0.03) returns a stable v1.0 JSON payload with verbatim transcript, language, time-indexed paragraphs, creator chapters, and canonical metadata (captions when available, Whisper fallback otherwise, no LLM rewrites). `POST /api/agents/engagement` ($0.02) returns view/like/comment counts, derived ratios, a composite engagement score, channel info (subscribers included), and full video context (tags, categories, thumbnail, availability, live status). Transparent cache on every response (`cache.hit`, `cachedAt`, `ageSec`) — transcripts are permanent, engagement refreshes every 6 hours. Typed error codes, OpenAPI 3.1, no signup. ([OpenAPI 3.1](https://flylabs.fun/api/agents/openapi.json)) ([Manifest](https://flylabs.fun/api/agents))

Agent commerce protocol for x402-style USDC payments on Base. Includes on-chain vendor/product registry, payment router, affiliate attribution, MCP endpoint, and live catalog API for agent-discoverable paid services. Current mainnet proof: 3 vendors, 8 on-chain products, 4 routed test payments. ([Catalog](https://pyrimid.ai/api/v1/catalog)) ([MCP](https://pyrimid.ai/api/mcp)) ([Skill](https://pyrimid.ai/skill.md))

EURC-priced, EU-sovereign compliance data for autonomous agents. EU VAT validation (VIES, all 27 member states) and pan-EU company data across 7 official registers (🇳🇴 🇫🇷 🇫🇮 🇸🇰 🇬🇧 🇱🇻 🇷🇴), normalized to one JSON schema with per-record provenance + open-data licence. €0.01–0.02/call — priced and settled in **EURC** (primary) or USDC on Base via the CDP facilitator. No API keys, no signup; country auto-detected from the id. ([Discovery](https://eurc402.com/.well-known/x402) | [OpenAPI](https://eurc402.com/openapi.json) | [Docs](https://eurc402.com/docs/human) | [llms.txt](https://eurc402.com/llms.txt))

Knowledge bookstore for AI agents: structured OKF knowledge bundles bought over x402. USDC on Base via CDP facilitator, gasless for the buyer; sealed zips with sha256 + signed receipts; open negentropy pricing formula. One free foundation bundle for ~1 month (founding-member on-chain record). Bazaar discovery extension on 402 responses. No API keys, no signup. ([Catalog](https://negbit.com/catalog.json)) ([llms.txt](https://negbit.com/llms.txt)) ([agents.txt](https://negbit.com/agents.txt))

Instant AI labor marketplace with three tiers: $5 quick polish (90s turnaround), $25 deep brief (1.5K-3K word structured deliverable), $99 full deliverable (pitch decks, RFPs, content calendars). Stripe + x402 ($0.05/call on bulk). Powered by Claude 4.7 Sonnet. ([Launch post](https://toughlovesec.win/blog/launch-clawwork-ai-labor-marketplace))

Universal data hub for AI agents — 17 cross-niche sources (crypto prices, ETH gas, weather, news, HN, GitHub trending, DeFi yield, token risk via GoPlus, HHS healthcare-breach feed, geocoding, more) behind one `POST /api/data/bundle` call. **Bundle micropayments save up to 92% vs per-API alternatives.** Day pass $0.99 unlimited 24h, week pass $4.99. Payable via x402 USDC OR Stripe Checkout — same `session_id` works across every tool call. Free 1-row preview at `/api/data/preview?type=…&q=…`. ([Live demo](https://toughlovesec.win/agent-mesh)) ([MCP server](https://github.com/atmflow55/datafood-mcp)) ([x402 descriptor](https://toughlovesec.win/.well-known/x402.json)) ([catalog](https://toughlovesec.win/api/v1/catalog))

Pay-per-image AI generation powered by Cloudflare Workers AI (Stable Diffusion XL Lightning + Flux-1-Schnell). Three tiers: $0.50 single, $1.99 12-pack, $7.99 100-bundle. Stripe Checkout for humans, x402 for agents at $0.04/image. No accounts, no expiring credits. ([Launch post](https://toughlovesec.win/blog/launch-imagegen-stripe-x402))

16 x402-paid services for AI agents on Base + Solana mainnet. 9 commodity primitives (OFAC sanctions screen, bundled wallet intel, dual-chain hash anchoring, signed attestations, mainnet tx + calldata decode, ENS + Bonfida SNS resolve, USD prices, datetime parse), 1 async due-diligence investigator ($7.77, 5–10 min, signed markdown report + dual-chain anchor proof), 1 verifiable signed RNG (`/v1/roll`, drop-in VRF for game studios), and 5 universal LLM endpoints (roast, oracle with on-chain anchored verdict, tldr, aura, grade). Plus a hosted chatbot at [chat.anchor-x402.com](https://chat.anchor-x402.com) — connect with passkey or any browser wallet, pay only when you approve. MCP server: [`anchor-x402-mcp`](https://www.npmjs.com/package/anchor-x402-mcp). ([GitHub](https://github.com/hypeprinter007-stack/anchor-x402)) ([Discovery](https://anchor-x402.com/.well-known/x402.json)) ([Trust portal](https://anchor-x402.com/trust))

Norway's AI agent API gateway — 7 live services, 23 endpoints covering Norwegian company registers (500K+ companies from Brønnøysundregistrene), SEO backlinks with Domain Rating, weather forecasts (MET Norway), 3,785 statistical tables (SSB), property/address data (Kartverket), IP search (Patentstyret), and public transport (Entur). $0.005–$0.10 USDC per query on Base via Coinbase CDP facilitator. No API keys, no accounts. ([services.json](https://x402agent.no/services.json)) ([llms.txt](https://x402agent.no/llms.txt))

Niche demand and competition intelligence for Kindle Direct Publishing authors. AI agents query keyword-level data including demand scores, competition intensity, BSR ranges, revenue estimates, and pricing analytics. $0.03 USDC per query on Base via CDP Facilitator. Free discovery endpoint lists all available niches. ([OpenAPI](https://nichedata.dev/openapi.json)) ([Docs](https://nichedata.dev/docs))

19 pay-per-call data tools for AI agents: crypto & DeFi market data (cross-exchange funding rates, market-regime signal, DeFi TVL/yields, stablecoin pegs), web extraction (text/Markdown/metadata), PDF-to-text, RSS parsing, FX, weather, DNS & email validation. $0.005–$0.02 USDC on Base via x402 v2, free Fear & Greed teaser, MCP server (`npx agent-data-api-mcp`). ([OpenAPI](https://agent-data-api-ui1c.onrender.com/openapi.json)) ([Discovery](https://agent-data-api-ui1c.onrender.com/.well-known/x402.json))

Web and PDF extraction APIs for AI agents with hallucination-guarded OCR: dual-engine consensus (VLM + traditional OCR), calibrated confidence, and honest disagree verdicts; Japanese-strong. Also invoice verification, schema-driven extraction, and JP company profiles. $0.001-$0.02 USDC per call on Base via x402 (CDP facilitator); free identical sandbox on Base Sepolia. Measured latency and success stats published. ([Docs](https://mart402.com/agents.md)) ([Sandbox](https://mart402.dev)) ([Stats](https://mart402.com/stats)) ([GitHub](https://github.com/tanaka-77/mart402-agent-kit))

Multi-venue perp funding & RWA spread API for arb-aware AI agents. 6 pay-per-call endpoints on Base mainnet ($0.001–$0.010 USDC): per-venue funding rates across 30+ exchanges (`/v1/funding/current`, $0.001), cross-venue funding spread (`/v1/perp/funding-spread?ticker=BTC`, $0.001), oracle price-source family classification for basis-risk awareness (`/v1/perp/oracle-families`, $0.001), RWA perpetual coverage on Hyperliquid HIP-3 DEXes — stocks, metals, forex, commodities, pre-IPO synthetics (`/v1/rwa/perp-coverage`, $0.001), **historical funding for backtesting** (`/v1/funding/historical?ticker=&from=&to=&aggr=1h|4h|1d`, $0.005, 90d retention), and **sized-depth quotes** with precomputed slippage at $1K/$5K/$10K notional (`/v1/orderbook/depth/aggregate/{venue}/{symbol}?size_usd=N`, $0.010). Differentiated vs CoinGecko/CMC by perp-first focus + RWA inclusion + backtestable historical depth. x402 v2 with Bazaar discovery extension via Coinbase CDP Facilitator. MCP server with 6 paid + 2 free tools at [namixai/usenami-mcp](https://github.com/namixai/usenami-mcp). ([API base](https://api.usenami.io)) ([Provider](https://usenami.io))

23 audit-verified pay-per-call utility endpoints for AI agents, settling in USDC on Base via Coinbase CDP Facilitator. Production fleet at `*.melis.ai`. Covers: web scraping ([ScrapePay](https://scrapepay.melis.ai/scrape) $0.01, Playwright + robots.txt-aware), HTML-to-markdown token reduction ([MarkdownOpt](https://markdownopt.melis.ai/markdown) $0.005), cached fetch ([CacheServe](https://cacheserve.melis.ai/fetch) $0.001), structured HTML extraction ([StructExtract](https://structextract.melis.ai/extract) $0.002), format conversion ([DocConvert-Text](https://docconvert-text.melis.ai/convert) $0.001, [DocConvert-PDF](https://docconvert-pdf.melis.ai/convert) $0.005), notifications ([NotifyRelay /email](https://notify.melis.ai/email) $0.005, [/notify (Telegram)](https://notify.melis.ai/notify) $0.002, [/webhook](https://notify.melis.ai/webhook) $0.001 HMAC-signed, SSRF-protected), JSON Schema validation ([SchemaGate](https://schemagate.melis.ai/validate-schema) $0.001), prompt-injection screening ([PromptGuard](https://promptguard.melis.ai/score) $0.002, [MemScrub](https://memscrub.melis.ai/scrub) $0.001), URL safety ([LinkRisk](https://linkrisk.melis.ai/profile) $0.005 lightweight, [LinkSafe](https://linksafe.melis.ai/verify) $0.01 Playwright+VirusTotal), embeddings + memory ([EmbedPay](https://embedpay.melis.ai/embed) $0.00005/1k tok, [MemoryServe /write](https://memoryserve.melis.ai/memory/write) $0.001, [/query](https://memoryserve.melis.ai/memory/query) $0.001), image moderation ([ImageGuard](https://imageguard.melis.ai/score) $0.002), wallet trust scoring ([KYA Oracle](https://kyaoracle.melis.ai/score) $0.005), response auditing ([xAudit](https://xaudit.melis.ai/validate) $0.002), multi-agent orchestration ([IntentFlow](https://intentflow.melis.ai/relay) $0.001, [LoopWall /issue](https://loopwall.melis.ai/issue) $0.001, [/hop](https://loopwall.melis.ai/hop) $0.0005). No API keys, no signup. ([MCP Server](https://www.npmjs.com/package/@melis-ai/x402-tools-mcp)) ([GitHub](https://github.com/mizukaizen/x402-tools-mcp)) ([Operator](https://melis.ai))

Crypto intelligence with a live, auditable per-signal-type win-rate at [/proof](https://n0brains.com/proof) (forward returns vs BTC, 95% CI; underperforming types demoted in the open). 6 pay-per-call x402 endpoints on Base, $0.005/signal USDC, no account: signals, rotation, correlation, DEX liquidation map, S/R levels, macro. Also hosted MCP (23 tools) and `pip install n0brains-cli`. ([Discovery](https://api.n0brains.com/.well-known/x402.json))

8 pay-per-call endpoints for AI agents on Solana mainnet, accepting **both USDC and USDT** (multi-token paywall). Includes `/audit-mcp` ($0.05, MCP server compliance + security audit), `/factcheck-fr` ($0.02, French fact-checking via Wikipedia FR + Claude verdict), `/translate-fr-pro` ($0.03, professional FR translation with business/legal/tech glossaries + tu/vous register), `/legal-fr-quickcheck` ($0.10, French clause audit vs RGPD + Code civil + Code conso + Code travail with article-precise violations), `/scrape-stealth` ($0.01, rotating UA HTTP scraper with CSS selectors + SSRF protection), `/agent-rep-check` ($0.05, Moltbook agent reputation snapshot — karma, age, breadth, score), `/submolt-recommend` ($0.02, semantic submolt ranking for a topic), and `/ai-act-mapping` ($2.00, EU AI Act Article 50 risk-tier mapping for SaaS products + CGU/UI compliance hooks). Self-hosted facilitator, multi-token settlement, no API keys, no signup. ([Discovery](https://x402-workers.kairos-lab.io/.well-known/x402)) ([Docs](https://x402-workers.kairos-lab.io/docs)) ([Manifest](https://x402-workers.kairos-lab.io/manifest)) ([Status](https://x402-workers.kairos-lab.io/status))

No-KYC cross-chain crypto swap API for AI agents — 1288+ assets aggregated across 3 providers (ChangeNOW, SimpleSwap, Heleket). **H2H Privacy Routing** automatically pipes any-to-any swaps through Monero so source and destination chains stay unlinkable on-chain. 10 MCP tools: `swap_quote`, `swap_create`, `swap_status`, `get_prices`, `get_assets`, `ai_chat` (Llama 3.3 70B), `check_portfolio`, `rug_check`, `create_wallet`, `set_price_alert`. $0.02 USDC on Base per MCP call (2 free/day per IP), $0.05 per `swap_create`, or €49.99/mo Agent Tier for unlimited via `X-License-Key` header. On-chain x402 verification with 10-min TX freshness + KV replay protection. ([MCP Server](https://swaptitan.net/mcp)) ([Pricing](https://swaptitan.net/pricing)) ([GitHub](https://github.com/polsolbridge/swaptitan-mcp)) ([Agent Card](https://swaptitan.net/.well-known/agent.json))

Post-payment trust and refund-evidence layer for AI agents using x402 endpoints. `/proofguard/evaluate` returns decision flags, receipt fields, trust scoring, and evidence links for Solana x402 calls. $0.003 USDC on Solana. ([GitHub](https://github.com/gra-kir/solsigs-proofguard)) ([x402scan](https://www.x402scan.com/server/e52b109e-420a-4e86-adf0-be7b5e12b302))

Solana token rug-risk intelligence for AI agents. One $0.01 USDC call (x402 v2, Solana mainnet) returns a composite CLEAN→RUGGED verdict from RugCheck + GoPlus + on-chain data, with LP-lock depth (per-pool TVL, locked %, burn %) and top-10 holder-lock status as structured fields, plus mint/freeze/close authority flags. Weighted multi-source scoring renormalizes when a source is down; fresh low-liquidity mints floor at MODERATE_RISK; buyers are never charged for 5xx. No API keys. ([Discovery](https://nexus-zero.xyz/)) ([MCP Server](https://nexus-zero.xyz/mcp))

15 pay-per-call USDC endpoints on Algorand mainnet: DeFi/DePIN data + non-custodial transaction builders (staking, LP farming, NFT mint, P2P). Unsigned atomic groups — agents sign with their own wallet. ([Catalog](https://fry.farm/x402/catalog) | [MCP](https://github.com/Fry-Foundation/fry-x402-mcp))

Pay-per-call market data and grid-trading params for AI agents, on Algorand mainnet via the GoPlausible facilitator. 3 endpoints: live P&L telemetry, price/signal check, and grid-parameter recommendation. $0.005-$0.05 USDC per call. ([Discovery](https://api-algo.stelardigital.com/.well-known/x402)) ([Catalog](https://api-algo.stelardigital.com/catalog))

Non-custodial agent utility market on Base with six API-key-free x402 services priced from $0.001 USDC, including endpoint and citation checks, agent-surface audits, live quote comparison, paid-work ranking, and GitHub issue-risk verification. Includes free JSON/MCP discovery and a technically verified, unendorsed public provider registry. ([x402 manifest](https://issuefoundry-index.jadennuckels.chatgpt.site/.well-known/x402)) ([MCP](https://issuefoundry-index.jadennuckels.chatgpt.site/api/mcp))

OpenAI-compatible LLM chat completions for AI agents on BNB Chain. deepseek-v4-flash at 0.02 $U per call via `POST /v1/chat/completions`, settled with EIP-3009 `transferWithAuthorization` (x402, scheme exact/eip3009 on eip155:56); the facilitator sponsors gas so the buyer needs only $U. No account, no API key. ([Agent Card](https://api.bortagent.xyz/.well-known/agent-card.json))

Structured, traceable S&P 500 financial intelligence for AI agents. 8 x402-paywalled endpoints ($0.01–$0.05 USDC on Base): company fundamentals, SEC Form 4 insider trades, 13F institutional holdings, industry peer ranking, multi-year CAGR trends, and smart-money bundles. SEC EDGAR-sourced with cross-source confidence scoring. No API keys, no signup. Open source (Apache 2.0). ([GitHub](https://github.com/fut66663/omninexu-v1)) ([Discovery](https://api.omninexu.com/.well-known/x402))

Trust verdict (trusted/caution/avoid) with wash-trading ratio, real-buyer count, and repeat-buyer rate for any x402 endpoint URL or pay-to address — deterministic economic-authenticity scoring computed from public on-chain settlement data, refreshed daily. $0.02 USDC per call on Base via CDP facilitator, free sample tool for schema validation. No API keys. ([MCP](https://x402score.org/mcp) | [Methodology](https://x402score.org/methodology) | [OpenAPI](https://x402score.org/openapi.json) | [llms.txt](https://x402score.org/llms.txt))

Measured ground-motion (subsidence & uplift) data for any US address, in mm/year from NASA OPERA Sentinel-1 InSAR — for AI agents assessing property, infrastructure, and climate risk. One report per call, $0.40 USDC on Base via the Coinbase CDP facilitator (402 responses carry the x402 `accepts` block; `X-PAYMENT` settles and serves in one round trip). Also honest prepaid-credit billing, no signup wall — one-call self-registration at `POST /api/v1/autonomous/register`. Hosted MCP server (9 tools), OpenAPI, and llms.txt. ([MCP](https://sibfly.com/mcp)) ([OpenAPI](https://sibfly.com/openapi.json)) ([llms.txt](https://sibfly.com/llms.txt))

Radio-frequency positioning DePIN for AI agents. Pay-per-call location APIs — estimate a position from cellular observations — plus receiver-node registration and status. USDC on **Solana and Base** (x402 v2), no API keys, $0.001-$0.10 per call, with machine-readable discovery and a Bazaar extension on every route. ([Discovery](https://azimuth.day/.well-known/x402)) ([Catalog](https://azimuth.day/api/x402/catalog))

Structured data on 5,336+ AI tools via REST API and MCP server. Search, compare, and retrieve tool profiles. USDC micropayments on Base. ([MCP Server](https://x402.aigregator.com/mcp))

Real-time X (Twitter) data API with 7 MPP/x402 pay-per-use endpoints — tweet lookup, tweet search, user lookup, follower check, article extraction, media download, and trends. No accounts or subscriptions required. ([GitHub](https://github.com/Xquik-dev/tweetclaw)) ([npm](https://www.npmjs.com/package/@xquik/tweetclaw)) ([MCP Server](https://xquik.com/mcp))

22 pay-per-query data APIs for AI agents — prediction markets (Polymarket + Manifold), property intelligence, sports odds, regulatory filings, FX rates, weather, IP geolocation, academic papers, document summarisation (Claude), and more. $0.001–$0.10 USDC per query on Base. No API keys or subscriptions. ([OpenAPI](https://api.devdrops.run/openapi.json)) ([Catalog](https://api.devdrops.run/catalog))

Provenance-stamped public-domain US government and scientific data for AI agents. SEC EDGAR, FRED, NOAA, openFDA, USGS, Crossref, and more — every record ships with a provenance URL back to its authoritative primary source. Pay-per-record x402 USDC on Base, $0.05–$0.50. Paid MCP server + listed in the official MCP Registry. No API keys, no subscriptions. ([MCP](https://api.osf-master-server.com/mcp) | [MCP Registry](https://registry.modelcontextprotocol.io/v0.1/servers?search=osf-data-marketplace) | [Bazaar health](https://api.osf-master-server.com/x402/bazaar_health))

Real-data feeds for AI agents, settling via Coinbase CDP Facilitator on Base mainnet. Three pay-per-call products with x402 v2 Bazaar discovery: `opportunities` ($0.01, Claude-scored AI revenue opportunities from real GitHub bounties), `verification` ($0.02, timestamped proof-of-execution receipts — HTTP status, latency, phantom/simulation detection so agents can confirm an A2A service is real before paying), and `benchmarks` ($0.02, real endpoint liveness & latency measurements for routing). All data sourced from verified live calls — no synthetic data. No API keys, no signup. Select product via `?product=<id>`. ([Discovery](https://kjtirbnxxymeumycrhqv.supabase.co/functions/v1/x402-seller?discover=1))

Universal swarm-intelligence engine exposed as a paid API: POST a scenario to the `/x402/run` surface and hundreds of grounded LLM personas simulate Twitter, Reddit, and a prediction market hour-by-hour, returning an analytical report. USDC on Base via x402. ([GitHub](https://github.com/aaronjmars/MiroShark))

Suite of 8 pay-per-call utility APIs settled in USDC on Base via x402 (free tier + one key for all): historical FX rates, color conversion, timezone/DST, fake/mock data, cron explainer, QR codes, data-format conversion, and encode/hash. ([FX](https://fx.wrapper-agency.com)) ([Color](https://color.wrapper-agency.com)) ([Timezone](https://tz.wrapper-agency.com)) ([Mock data](https://mock.wrapper-agency.com)) ([Cron](https://cron.wrapper-agency.com)) ([QR](https://qr.wrapper-agency.com)) ([Data format](https://data.wrapper-agency.com)) ([Encode](https://encode.wrapper-agency.com))

Agent-readable paid JSON research endpoints on Base USDC: stock-screen reports plus Polymarket/trading-agent analysis with structured rankings, risks, provenance, and disclaimers. $0.001 USDC per resource, no API key or account. ([Catalog](https://darrylbots.com/x402.json)) ([x402scan](https://www.x402scan.com/server/35285845-c871-4694-847b-c9b727cb474f))

Utility API suite for AI agents on x402. 7 pay-per-call services on Base mainnet, no API keys, no signup: `Bismuth Scraping` ($0.02 scrape / $0.10 BFS crawl — Playwright, SSRF-protected), `Bismuth Screenshot` ($0.01, Playwright PNG/JPEG), `Bismuth PDF Extraction` ($0.01, OCR + vision mode), `Bismuth Email` ($0.01, Resend + CC/BCC/attachments), `Bismuth Search` ($0.01, Tavily-ranked), `Bismuth Conversion` ($0.02 — image reformat, CSV→JSON, HTML→PDF, DOCX→PDF), `Bismuth Crypto Intelligence` ($0.01–$0.10, CoinGecko/DeFiLlama/CoinTelegraph/GitHub across 17 major coins). MCP server ships all tools under one npm install with automatic USDC micropayments. ([MCP Server](https://www.npmjs.com/package/x402-mcp-server) | [Scraping Discovery](https://x402-scraping-api-production.up.railway.app/.well-known/x402) | [Screenshot Discovery](https://usdc-screenshot-api-production.up.railway.app/.well-known/x402) | [PDF Discovery](https://pdf-api-production-cf1e.up.railway.app/.well-known/x402) | [Email Discovery](https://x402-email-api-production.up.railway.app/.well-known/x402) | [Search Discovery](https://x402-search-api-production.up.railway.app/.well-known/x402) | [Conversion Discovery](https://x402-conversion-api-production.up.railway.app/.well-known/x402) | [Crypto Discovery](https://crypto-sentiment-api-production-0ff4.up.railway.app/.well-known/x402))

Informational Bittensor allocation analysis API for AI agents, paid with x402 v2 USDC on Base. Supports walletless model portfolio snapshots, wallet-specific preflight flows, OpenAPI, read-only MCP, and llms.txt discovery. ([OpenAPI](https://api.stakao.com/agent/openapi.json) | [Docs](https://stakao.com/docs/ai-agents.md) | [llms.txt](https://stakao.com/llms.txt))

Surplus lines market data, per query. U.S. excess & surplus (E&S) insurance premium and policy-count statistics from state stamping office publications: time series, YoY summaries, and cross-state comparison by state, coverage line, and month/quarter/year. $0.10 single-state query, $0.50 cross-state compare, USDC on Base via CDP facilitator with Bazaar discovery. Free discovery endpoints, no API keys or signup; every response cites its source report. ([OpenAPI](https://api.querylines.com/openapi.json)) ([MCP Server](https://api.querylines.com/mcp)) ([llms.txt](https://querylines.com/llms.txt))

Crypto market microstructure and options metrics for AI agents: VPIN, Kyle's lambda, roll spread, order-flow imbalance, BTC options (GEX, expected move, variance risk premium), Polymarket, Hyperliquid, and on-chain activity, plus an AI-written BTC market summary. $0.05–$0.25 USDC per call on Base via the Coinbase CDP facilitator; x402 v2 with Bazaar discovery on every 402. No API keys, no signup. ([OpenAPI](https://api.dripmetrics.ai/openapi.json)) ([MCP Server](https://mcp.dripmetrics.ai/mcp)) ([GitHub](https://github.com/DripMetricsAI/dripmetrics-mcp))

41 pay-per-call endpoints for AI agents, all $0.001–$0.009 USDC on Base via CDP facilitator: web scraping, document extraction (PDF/DOCX/CSV), single-page and whole-site SEO/accessibility audits, brand-kit/logo/icon/social-card generation, multi-page website building, DNS & email intelligence, geolocation, crypto data, a free machine message board, and a wallet-owned persistent Agent Datastore — give your agent a memory. Free 402 previews on page-check endpoints. No API keys, no signup. ([Discovery](https://api.webbersites.com/.well-known/x402)) ([OpenAPI](https://api.webbersites.com/openapi.json)) ([MCP Server](https://api.webbersites.com/mcp)) ([npm](https://www.npmjs.com/package/webbersites-x402-mcp)) ([GitHub](https://github.com/webberdesign/api.webbersites.com))

Astrology full charts, transit/mundane aspect time series, and global location data for AI agents. Flat $0.50 per request, x402 v2 USDC on Base mainnet plus MPP (Stripe/Tempo) on the same routes. No API keys, no signup. ([OpenAPI](https://astro.dutchdata.io/openapi.json)) ([llms.txt](https://astro.dutchdata.io/llms.txt)) ([Agent Card](https://astro.dutchdata.io/.well-known/agent-card.json))