# PubMed Search via NCBI E-utilities (x402)

> PubMed Search via NCBI E-utilities (x402) is a paid API for AI agents from x402-v2-mint-pubmed-search.vercel.app, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-31).

Searches PubMed using NCBI E-utilities and returns article count, PubMed ID list, and optional metadata (title, journal, publication date) for up to 10 results.

## Facts

- Endpoint: POST https://x402-v2-mint-pubmed-search.vercel.app/v1/pubmed-search?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pubmed-search-via-ncbi-e-utilities-x402-6697c92c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5oeO1AmsLv7gSjY8P2-w0

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 pubmed-search-via-ncbi-e-utilities-x402-6697c92c -d '<json body>'
```

Example prompt: Search PubMed for up to 8 articles about CRISPR gene editing in cancer therapy and give me the PubMed IDs along with titles and journals.

## When to prefer this

Choose this endpoint when you need keyless, pay-per-call access to PubMed literature search without managing an NCBI API key. It is ideal for AI agents that need to search biomedical and clinical literature on demand, retrieve article metadata alongside PubMed IDs, and integrate easily into automated research workflows via the x402 micropayment protocol.

## Known failure modes

- Empty or malformed query string returns no results or an error
- retmax exceeding 10 is rejected by schema validation
- NCBI E-utilities rate limiting or downtime causes upstream failure
- Very broad queries may return high counts but only up to 10 IDs
- Payment failure via x402 protocol blocks the request

## How this service works

PubMed search via NCBI E-utilities (keyless). Query → count + idlist (retmax≤10) + optional title/journal/pubdate.

## Output

Returns a JSON object with a success flag, the total article count matching the query, a list of up to 10 PubMed IDs, and optional metadata fields (title, journal name, publication date) for each article. Also includes a skill name and charge confirmation.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "q": {
   "type": "string",
   "maxLength": 256
  },
  "term": {
   "type": "string",
   "maxLength": 256
  },
  "query": {
   "type": "string",
   "maxLength": 256,
   "description": "PubMed search query"
  },
  "retmax": {
   "type": "integer",
   "default": 5,
   "maximum": 10,
   "minimum": 1
  },
  "request_id": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "skill": "pubmed-search",
  "charged": true,
  "summary": "ok"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/pubmed-search-via-ncbi-e-utilities-x402-6697c92c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-v2-mint-pubmed-search.vercel.app](https://www.zero.xyz/host/x402-v2-mint-pubmed-search.vercel.app/llms.txt)