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2s.io Scientific Literature Search
x402
2s.io Scientific Literature Search is a paid API for AI agents from 2s.io, paid per call via x402, $0.0024/call, status unknown (last checked 2026-09-13).
Search for academic papers across arXiv, PubMed, and Semantic Scholar simultaneously, returning a unified flat list with source, DOI, title, authors, abstract, year, citation count, and PDF links.
Price / call$0.0024
Success—
StatusUnknown
How this service works
Unified scientific literature search across arXiv (preprints), PubMed (biomedical), and Semantic Scholar (cross-field, with citation counts). Returns a flat array of papers with stable schema: source, sourceId, doi, title, authors, abstract, year, publishedAt, citationCount, url, pdfUrl. Partial failures surface in the errors array rather than failing the whole call. Optional filters: since (YYYY-MM-DD), sources (subset), limit (max 20 per source).
Output
A flat JSON array of papers, each with fields: source (arXiv/PubMed/Semantic Scholar), sourceId, doi, title, authors, abstract, year, publishedAt, citationCount, url, and pdfUrl. Partial source failures are surfaced in a separate errors array rather than aborting the whole response.
Example use cases
Example prompt
“Search for up to 15 papers on CRISPR gene editing published since 2022, pulling from arXiv, PubMed, and Semantic Scholar so I can see citation counts and grab PDF links.”
Technical details
Endpoint
GEThttps://2s.io/api/papers/searchWhen to prefer
Use this endpoint when you need to search academic literature across multiple scientific databases simultaneously and want a unified, stable schema with citation counts and PDF links. Prefer it over individual API calls to arXiv, PubMed, or Semantic Scholar when you want aggregated cross-domain results in a single call with graceful partial-failure handling.
Side effects
- One or more upstream sources (arXiv, PubMed, Semantic Scholar) unavailable — partial results returned with errors array populated
- Query string too long (>500 chars) — 400 validation error
- Invalid 'since' date format (not YYYY-MM-DD) — 400 validation error
- limit exceeds 20 — 400 validation error
- No results found for query — empty array returned
- Payment not provided or insufficient — 402 Payment Required
Input
{
"input": {
"type": "http",
"method": "GET",
"queryParams": {
"q": "machine learning",
"limit": 10
}
}
}Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object |
Output
{
"data": {
"ok": true,
"meta": {
"query": "machine learning",
"errors": [
{
"source": "semantic-scholar",
"message": "semantic-scholar HTTP 429"
},
{
"source": "arxiv",
"message": "This operation was aborted"
}
],
"sources": [
"arxiv",
"pubmed",
"semantic-scholar"
],
"attribution": [
{
"url": "https://arxiv.org/help/api/terms-of-use",
"source": "arxiv",
"license": "arXiv non-exclusive license — terms permit programmatic access"
},
{
"url": "https://www.nlm.nih.gov/databases/download/pubmed_medline.html",
"source": "pubmed",
"license": "Public domain (US government work)"
},
{
"url": "https://www.semanticscholar.org/product/api/license",
"source": "semantic-scholar",
"license": "CC0 1.0 (metadata)"
}
]
},
"items": [
{
"doi": "10.1111/joim.12822",
"url": "https://pubmed.ncbi.nlm.nih.gov/30102808/",
"year": 2018,
"title": "eDoctor: machine learning and the future of medicine.",
"pdfUrl": null,
"source": "pubmed",
"authors": [
"Handelman GS",
"Kok HK",
"Chandra RV",
"Razavi AH",
"Lee MJ",
"Asadi H"
],
"abstract": null,
"sourceId": "30102808",
"publishedAt": "2018 Dec",
"citationCount": null
},
{
"doi": "10.23736/S2724-5683.21.05709-4",
"url": "https://pubmed.ncbi.nlm.nih.gov/34338485/",
"year": 2022,
"title": "Machine learning for cardiology.",
"pdfUrl": null,
"source": "pubmed",
"authors": [
"Arfat Y",
"Mittone G",
"Esposito R",
"Cantalupo B",
"DE Ferrari GM",
"Aldinucci M"
],
"abstract": null,
"sourceId": "34338485",
"publishedAt": "2022 Feb",
"citationCount": null
},
{
"doi": "10.1016/j.beth.2020.05.002",
"url": "https://pubmed.ncbi.nlm.nih.gov/32800297/",
"year": 2020,
"title": "Supervised Machine Learning: A Brief Primer.",
"pdfUrl": null,
"source": "pubmed",
"authors": [
"Jiang T",
"Gradus JL",
"Rosellini AJ"
],
"abstract": null,
"sourceId": "32800297",
"publishedAt": "2020 Sep",
"citationCount": null
},
{
"doi": "10.1016/j.drudis.2021.09.007",
"url": "https://pubmed.ncbi.nlm.nih.gov/34560276/",
"year": 2022,
"title": "Machine-learning methods for ligand-protein molecular docking.",
"pdfUrl": null,
"source": "pubmed",
"authors": [
"Crampon K",
"Giorkallos A",
"Deldossi M",
"Baud S",
"Steffenel LA"
],
"abstract": null,
"sourceId": "34560276",
"publishedAt": "2022 Jan",
"citationCount": null
},
{
"doi": "10.1146/annurev-clinpsy-032816-045037",
"url": "https://pubmed.ncbi.nlm.nih.gov/29401044/",
"year": 2018,
"title": "Machine Learning Approaches for Clinical Psychology and Psychiatry.",
"pdfUrl": null,
"source": "pubmed",
"authors": [
"Dwyer DB",
"Falkai P",
"Koutsouleris N"
],
"abstract": null,
"sourceId": "29401044",
"publishedAt": "2018 May 7",
"citationCount": null
},
{
"doi": "10.1161/HYPERTENSIONAHA.124.19468",
"url": "https://pubmed.ncbi.nlm.nih.gov/38380541/",
"year": 2024,
"title": "AI, Machine Learning, and ChatGPT in Hypertension.",
"pdfUrl": null,
"source": "pubmed",
"authors": [
"Layton AT"
],
"abstract": null,
"sourceId": "38380541",
"publishedAt": "2024 Apr",
"citationCount": null
},
{
"doi": "10.1002/adma.202102703",
"url": "https://pubmed.ncbi.nlm.nih.gov/34617632/",
"year": 2022,
"title": "Machine Learning-Driven Biomaterials Evolution.",
"pdfUrl": null,
"source": "pubmed",
"authors": [
"Suwardi A",
"Wang F",
"Xue K",
"Han MY",
"Teo P",
"Wang P",
"Wang S",
"Liu Y",
"Ye E",
"Li Z",
"Loh XJ"
],
"abstract": null,
"sourceId": "34617632",
"publishedAt": "2022 Jan",
"citationCount": null
},
{
"doi": "10.1016/S2352-3026(20)30121-6",
"url": "https://pubmed.ncbi.nlm.nih.gov/32589980/",
"year": 2020,
"title": "Machine learning in haematological malignancies.",
"pdfUrl": null,
"source": "pubmed",
"authors": [
"Radakovich N",
"Nagy M",
"Nazha A"
],
"abstract": null,
"sourceId": "32589980",
"publishedAt": "2020 Jul",
"citationCount": null
},
{
"doi": "10.1007/s10529-024-03499-8",
"url": "https://pubmed.ncbi.nlm.nih.gov/38902585/",
"year": 2024,
"title": "Machine learning: an advancement in biochemical engineering.",
"pdfUrl": null,
"source": "pubmed",
"authors": [
"Saha R",
"Chauhan A",
"Rastogi Verma S"
],
"abstract": null,
"sourceId": "38902585",
"publishedAt": "2024 Aug",
"citationCount": null
},
{
"doi": "10.1111/ijlh.14110",
"url": "https://pubmed.ncbi.nlm.nih.gov/37257440/",
"year": 2023,
"title": "Applied machine learning in hematopathology.",
"pdfUrl": null,
"source": "pubmed",
"authors": [
"Dehkharghanian T",
"Mu Y",
"Tizhoosh HR",
"Campbell CJV"
],
"abstract": null,
"sourceId": "37257440",
"publishedAt": "2023 Jun",
"citationCount": null
}
],
"total": 10,
"source": {
"url": "https://2s.io/papers/search",
"license": "Mixed open licenses; see meta.attribution",
"provider": "2s.io aggregation over arXiv + PubMed + Semantic Scholar"
}
},
"meta": {
"cost": {
"usd": 0.0024,
"tier": 0
},
"caller": "x402",
"version": null,
"endpoint": "papers.search",
"settlement": {
"txHash": "0x927d1a4f29b9c6e7b53619cff0292ec81f58d7b14005e77c1bbe1d5290cd62cd",
"network": "eip155:8453",
"success": true
}
}
}Tags
x402
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