# NCBI NLM Catalog E-Search

> NCBI NLM Catalog E-Search is a paid API for AI agents from clonecho.builda.company, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-13).

Searches the NCBI NLM Catalog journal and resource database and returns matching UIDs for a given query using NCBI E-utilities.

## Facts

- Endpoint: POST https://clonecho.builda.company/x402/s/ncbi-esearch-nlmcatalog
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/ncbi-nlm-catalog-e-search-da572e36
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_eQpRnejawpYuxhRdpKyVQ

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 ncbi-nlm-catalog-e-search-da572e36 -d '<json body>'
```

Example prompt: Search the NCBI NLM Catalog for journals matching 'nature medicine' and give me the UIDs.

## When to prefer this

Use this endpoint when you need to look up NLM Catalog UIDs for biomedical journals or resources by name or keyword, particularly as a first step in an NCBI E-utilities workflow (e.g., before fetching full records via EFetch). Prefer this over direct NCBI API calls when you need a pay-per-use, proxied access point to NLM Catalog search.

## Known failure modes

- Empty result set if no journals match the query
- Payment failure (402) if USDC not provided
- Malformed query returns error or empty UID list
- NCBI API rate limits or downtime causing timeouts

## How this service works

Search the NCBI NLM Catalog journal/resource database and return matching UIDs for query {q} via E-utilities. Query: ?q= Returns JSON.

## Output

A JSON response containing a list of NLM Catalog UIDs (record identifiers) that match the search query, retrieved via NCBI E-utilities.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ncbi-nlm-catalog-e-search-da572e36/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from clonecho.builda.company](https://www.zero.xyz/host/clonecho.builda.company/llms.txt)