# NCBI PubChem Compound Search via E-utilities

> NCBI PubChem Compound Search via E-utilities 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 PubChem Compound chemical database using E-utilities and returns matching compound UIDs for a given query string.

## Facts

- Endpoint: POST https://clonecho.builda.company/x402/s/ncbi-esearch-pccompound
- 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-pubchem-compound-search-via-e-utilities-08a8a2a1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_upXSgefyjfY6S9Kb5gmk2

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-pubchem-compound-search-via-e-utilities-08a8a2a1 -d '<json body>'
```

Example prompt: Can you search PubChem for compounds matching 'ibuprofen' and give me the compound UIDs?

## When to prefer this

Use this endpoint when you need to resolve chemical names, CAS numbers, molecular formulas, or other identifiers to PubChem Compound UIDs (CIDs), especially when integrating with downstream NCBI/PubChem API calls that require CIDs. Prefer this over manual PubChem web lookups or direct NCBI E-utilities calls when you want a simple pay-per-call REST interface without managing API keys.

## Known failure modes

- Empty result set if no compounds match the query string
- Invalid or malformed query string may return zero results or an error
- NCBI E-utilities rate limiting or downtime causing failed requests
- Payment failure (insufficient USDC balance) returning 402 error
- Query too vague returning an unexpectedly large number of UIDs

## How this service works

Search the NCBI PubChem Compound chemical database and return matching UIDs for query {q} via E-utilities. Query: ?q= Returns JSON.

## Output

A JSON response containing matching PubChem Compound UIDs (CIDs) for the query, along with result count metadata as returned by the NCBI E-utilities esearch endpoint targeting the pccompound database.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ncbi-pubchem-compound-search-via-e-utilities-08a8a2a1/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)