Research data APIs for AI agents, paid per call
Paid APIs for papers, datasets and research results, that an AI agent can call and pay for on the spot with x402, in USDC. We list 30, from 20 sellers. 21 are live and asking for payment correctly, and 6 delivered when we bought from them with real money. The typical price is $0.03 a call (half ask between $0.01 and $3.00).
The APIs
The first 30, in the same order as our search (GET /v1/discover?category=data.research, testnets left out): verified first, then probe score, then price.
Nobody can pay for a place here. Each name opens the full record: every check, every purchase, with dates.
| API | price | status | when we bought |
|---|---|---|---|
| ArXiv AI/CS Paper Search & Structured Token-Diet Digest (arxiv-digest)free samplearxiv-digest-72343955726.us-central1.run.app | $0.01 | verified | bought, delivered 2026-10-19 |
| Tensorfeed — Research Milestonesfree sampletensorfeed.ai | $0.02 | verified | bought, delivered 2026-09-01 |
| Diabetes Skill Bible — cited research brieffree samplegoqzr.thebay.cloud | $0.05 | verified | probes pass; not bought yet |
| Diabetes Skill Bible — competitor teardownfree samplegoqzr.thebay.cloud | $0.05 | verified | probes pass; not bought yet |
| LLMs-Generator Gateway — ArXiv & Semantic Scholar Research Synthesizerfree samplellms-generator-72343955726.us-central1.run.app | $0.01 | verified | bought, delivered 2026-10-30 |
| Tensorfeed — Research Citation Velocityfree sampletensorfeed.ai | $0.02 | verified | bought, delivered 2026-09-01 |
| JurisRAG APIfree samplejurisrag-api.lcalado.chatgpt.site | $0.01 | verified | probes pass; not bought yet |
| ai_progress_latest — Tokenized Stocks & Agent Data (x402)free samplex402-accelerometer-feed.fly.dev | $0.005 | verified | probes pass; not bought yet |
| BlindOracle — research.topic-sentiment-analyzerfree sampleapi.craigmbrown.com | $0.03 | verified | bought, did not deliver |
| AgentIndex Research Jobsfree samplex402.agentindex.world | $1.00 | verified | probes pass; not bought yet |
| Source Ledger: New York small-bank snapshotfree sampleindtjening-source-ledger.ligeudafposen.chatgpt.site | $0.01 | verified | probes pass; not bought yet |
| ZGAS-002 Base USDC Receipt Checklistpublish.new | $3.00 | verified | probes pass; not bought yet |
| Overwing Atlas report: what AI agents do and what they spendoverwing.ai | $9.00 | verified | probes pass; not bought yet |
| DESK LEAD — Research Pack 50desk-x402.desk-x402-gh.workers.dev | $50.00 | verified | probes pass; not bought yet |
| DESK LEAD — Research Pack 100desk-x402.desk-x402-gh.workers.dev | $100.00 | verified | probes pass; not bought yet |
| DESK LEAD — Day Retainer Pack 150desk-x402.desk-x402-gh.workers.dev | $150.00 | verified | probes pass; not bought yet |
| ZGAS-001 Quickstart excerptpayanagent.com | $2.00 | verified | probes pass; not bought yet |
| x402.ochinimus.app/api/papers | $0.015 | verified | probes pass; not bought yet |
| x402 Scholarly Paper Search (OpenAlex + Crossref)x402-web-tools.microtools-x402.workers.dev | $0.005 | verified | bought, delivered 2026-10-30 |
| ZGAS-001 Zero-Gas Agent Commerce Field Guidepublish.new | $5.00 | verified | probes pass; not bought yet |
| AgentIndex Fact Checkx402.agentindex.world | $0.05 | verified | probes pass; not bought yet |
| CedarProof commission opportunity packfree samplecedarproof-diagnostics.cedarproof-lab.workers.dev | $0.05 | failing | failing its checks |
| Saymon RU Data API — Russian market research (deep)free samplewww.payforapi.com | $0.05 | failing | failing its checks |
| Saymon RU Data API — Russian market researchfree samplewww.payforapi.com | $0.02 | failing | bought, delivered 2026-09-01 |
| Quant Agent Shop: Cited Research Answerquantagentshop.com | $0.0099 | failing | failing its checks |
| BABYDOV Source-Backed Research Briefvps-62-120.cloudhosting.lv:8443 | $1.50 | failing | failing its checks |
| BABYDOV Market Research Provps-62-120.cloudhosting.lv:8443 | $6.00 | failing | failing its checks |
| BABYDOV Source Evidence Checkvps-62-120.cloudhosting.lv:8443 | $0.01 | failing | failing its checks |
| BABYDOV Agent Research Work Ordervps-62-120.cloudhosting.lv:8443 | $1.00 | failing | failing its checks |
| Clarity research reportdesktop-o99r0sf.tail935fba.ts.net | $2.00 | failing | failing its checks |
All of them, as data: api.nohumans.directory/v1/discover?category=data.research&limit=50. Live figures, as of 2026-11-07 02:39 UTC.
For agents
Search this kind of API from your agent, free, no key. MCP server https://api.nohumans.directory/mcp, tool
find_paid_service with {"category": "data.research", "query": "what you need"}, or REST:
GET https://api.nohumans.directory/v1/discover?category=data.research&q=<what you need>
Before paying any endpoint, check its record: how, and when not to pay.
Sell one
20 sellers already list Research data APIs here, at a typical $0.03 a call. Agents choose on evidence: a free sample, inputs they can read, and a purchase that delivered. Check yours free and list it · what x402 APIs charge and earn · build one with one prompt.
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Figures count active listings on mainnet, tunnels and testnets excluded; prices are the live payment requests of verified listings on Base. Records are dated evidence about how an endpoint behaved, not a guarantee. How we check.