PubChem PUG REST API
Power User Gateway (PUG) REST service for chemical compounds, SMILES/InChI structures, molecular formulas, toxicology and bioassays.
When is this useful?
Cheminformatics, laboratory software and retrieving molecular properties by compound name, CID or InChIKey.
Access & pricing
No key
No API key required for public chemical structure, property and bioassay queries.
Free
Public service of the U.S. National Library of Medicine (NIH/NCBI) at no cost.
Get your own key only from the provider. Never enter keys or tokens here.
Limitations & terms
Dynamic traffic throttling enforces a ceiling of roughly 5 requests per second per client.
Commercial use: Allowed per source
No terms source recorded; permission has not been established.
Provenance & attributes
Kind: api · HTTPS: unknown · CORS: unknown
Sources: profiles
Categories: Science ·
Related guides
From discovery to implementation
Build with understanding.
Practical API integration guides, separate from catalog listings.
All guides →- GeoJSON to a map: valid numbers do not prove coordinate order →
- Read a damaged JSON sequence without pretending it is complete →
- JSON intake: reject ambiguous bytes before checking the resource schema →
- Read Problem Details without turning an error message into a decision rule →
- A relative API link is not text to append to a domain →
A guide for your situation
Your answers stay in this page until you explicitly submit them. Unsaved answers disappear on reload.
Saving is not configured. No answers or contact details are submitted or saved.
Which integration step helps you move forward?
30 short questions about APIs and connecting data. Selecting an answer moves to the next question. You can go back, change answers, or skip. This is a practical reading route, not a scientific test.
JavaScript is required for this guide.
Contact & corrections
Send a question or report a correction using this form.
Only after Send are your name, email, subject and message sent to the contact service to handle your message. This is not a newsletter signup. Unsent text disappears on reload. Privacy information
Preview: sending is not configured. This form does not send or save anything.