# PubMed Biomedical Literature Search via NCBI E-utilities

> PubMed Biomedical Literature Search via NCBI E-utilities is a paid API for AI agents from x402-deployer.x402-deployer.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Searches PubMed for biomedical articles by free-text query with optional date range and sort order, returning PMIDs, titles, authors, journals, abstracts, MeSH terms, and DOIs

## Facts

- Endpoint: POST https://x402-deployer.x402-deployer.workers.dev/pubmed-search
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-deployer-x402-deployer-workers-dev-4c3d44d5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_s5WUvm8b6OqmT37x1dpdL

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability x402-deployer-x402-deployer-workers-dev-4c3d44d5 -d '<json body>'
```

Example prompt: Search PubMed for the top 10 most relevant papers on CRISPR gene editing for sickle cell disease published between 2020 and 2024, sorted by relevance, and give me the titles, authors, abstracts, and DOIs.

## When to prefer this

Choose this endpoint when you need structured biomedical literature data from PubMed/NCBI including abstracts, MeSH terms, and DOIs — especially when you want date-filtered or relevance-sorted results without managing an NCBI API key. Prefer over raw NCBI calls for its simplified POST interface and x402 micropayment integration.

## Known failure modes

- Query too broad returns very high hit count with low precision results
- Date range yields no results if no papers exist in that window
- Malformed or empty query string returns an error or zero results
- NCBI E-utilities rate limit hit if called at high frequency without delay
- DOI or MeSH terms may be absent for older or preprint-indexed records

## How this service works

PubMed search / biomedical literature search / medical journal lookup / NIH paper search / clinical-research finder / MeSH-term query / NCBI E-utilities wrapper. Searches PubMed for biomedical articles by free-text query, with optional date range and sort (relevance / pub_date / first_author). Returns total hit count plus PMID, title, authors, journal, publication date, abstract, MeSH terms, and DOI per paper. Federal public domain via NCBI E-utilities — no API key required.

## Output

Returns the total number of matching records plus a list of articles each containing: PMID, title, author list, journal name, publication date, full abstract, MeSH terms, and DOI. Results are paginated/limited by the requested count and sorted by the chosen sort field.

## Request schema (JSON Schema)

```json
{
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "type": "object",
 "properties": {
  "input": {
   "type": "object",
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "type": "string",
     "enum": [
      "POST"
     ]
    },
    "bodyType": {
     "type": "string",
     "enum": [
      "json",
      "form-data",
      "text"
     ]
    },
    "body": {
     "properties": {
      "query": {
       "type": "string",
       "description": "PubMed query string. Supports field tags ('cancer[Title]', 'Smith J[Author]'), boolean operators, and MeSH terms."
      },
      "limit": {
       "type": "number",
       "description": "Max papers to return. 1-50. Default 10."
      },
      "date_from": {
       "type": "string",
       "description": "Lower bound on publication date (YYYY/MM/DD or YYYY-MM-DD)."
      },
      "date_to": {
       "type": "string",
       "description": "Upper bound on publication date (YYYY/MM/DD or YYYY-MM-DD)."
      },
      "sort": {
       "type": "string",
       "enum": [
        "relevance",
        "pub_date",
        "first_author"
       ],
       "description": "Result ordering. Default 'relevance'."
      },
      "include_abstract": {
       "type": "boolean",
       "description": "If true (default), include the abstract text per paper. Set false for a smaller, faster response."
      }
     },
     "required": [
      "query"
     ]
    }
   },
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "query": {
       "type": "string"
      },
      "sort": {
       "type": "string"
      },
      "date_from": {
       "type": "null"
      },
      "date_to": {
       "type": "null"
      },
      "total": {
       "type": "integer"
      },
      "returned": {
       "type": "integer"
      },
      "papers": {
       "type": "array",
       "items": {
        "type": "object",
        "properties": {
         "pmid": {
          "type": "string"
         },
         "title": {
          "type": "string"
         },
         "authors": {
          "type": "array",
          "items": {
           "type": "string"
          }
         }
        }
       }
      },
      "source": {
       "type": "string"
      }
     }
    }
   },
  
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-deployer-x402-deployer-workers-dev-4c3d44d5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-deployer.x402-deployer.workers.dev](https://www.zero.xyz/host/x402-deployer.x402-deployer.workers.dev/llms.txt)