PubChem Compound Search & Lookup — Official NIH API

Resolve compound names or PubChem CIDs against the official NIH PubChem PUG REST API and export compact chemical-property rows.

Use it for compound lookup, chemistry data normalization, research datasets, identifier resolution, chemical informatics, and automated PubChem workflows.

Independent tool. Not affiliated with or endorsed by NIH, NCBI, or PubChem. Not medical, toxicology, laboratory, or regulatory advice.

Common use cases

• Resolve common compound names to PubChem CIDs
• Look up known CIDs and retrieve standard chemical properties
• Normalize compound identifiers for research datasets
• Collect molecular formula, mass, SMILES, InChI, and related properties
• Feed structured PubChem records into downstream research workflows

What you get

Successful rows include PubChem CID/title, molecular formula/weight, SMILES, InChI/InChIKey, IUPAC name, XLogP, exact and monoisotopic mass, TPSA, complexity, hydrogen-bond counts, rotatable-bond count, heavy-atom count, and formal charge when returned.

Try it

{
  "queries": ["aspirin", "caffeine", "2244"],
  "queryType": "auto"
}

Source

PubChem PUG REST: https://pubchem.ncbi.nlm.nih.gov/rest/pug

PubChem asks automated clients to stay at or below 5 requests per second and may dynamically throttle traffic. This Actor globally spaces upstream calls to about 4 requests/second and retries transient 429/5xx/503 failures with backoff.

Important limitations

Not-found inputs emit diagnostic rows. If every input is unresolved, the Actor also emits a non-billed zero-result summary.

This Actor reports source chemical data. It does not determine medical suitability, toxicity, laboratory safety, regulatory status, or appropriate handling/use of a compound.

Pricing

Only successfully resolved compound rows are billed. Not-found diagnostic rows, zero-result summaries, and budget-limit summaries are not billed.

Candidate target: $0.25 per 1,000 resolved compound rows, subject to live economics and the strengthened release gate.

About Piven Core

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Learn more: https://pivencore.com