name: PubChem description: PubChem is NCBI's open chemistry database containing information on more than 100 million chemical compounds. It provides REST and view APIs for searching chemical structures, retrieving molecular properties, bioactivity data, safety information, and drug information. PubChem integrates data from hundreds of data sources and is freely accessible without authentication for standard use. image: https://pubchem.ncbi.nlm.nih.gov/favicon.ico tags: - Chemistry - Chemical Compounds - Drug Discovery - Bioassay - Life Sciences - NCBI - Bioinformatics url: https://pubchem.ncbi.nlm.nih.gov/ created: "2026-06-13" modified: "2026-06-13" specificationVersion: "0.19" apis: - name: PubChem PUG REST API description: The Power User Gateway (PUG) REST API provides programmatic access to PubChem compound, substance, and bioassay data. Supports lookup by name, CID, SID, InChI, SMILES, and structure search. Returns molecular properties, identifiers, 2D/3D structures, bioactivity summaries, cross-references, synonyms, and images. humanURL: https://pubchem.ncbi.nlm.nih.gov/docs/pug-rest baseURL: https://pubchem.ncbi.nlm.nih.gov/rest/pug tags: - Compounds - Substances - Bioassays - Structure Search - Chemical Properties properties: - type: Documentation url: https://pubchem.ncbi.nlm.nih.gov/docs/pug-rest - type: OpenAPI url: https://pubchem.ncbi.nlm.nih.gov/rest/pug/openapi.json contact: - FN: PubChem Help Desk email: pubchem-help@ncbi.nlm.nih.gov operations: - summary: Get compound by CID method: GET path: /compound/cid/{cid}/JSON description: Retrieve full compound record by PubChem Compound ID (CID) in JSON format. - summary: Get compound by name method: GET path: /compound/name/{name}/JSON description: Retrieve compound records by chemical name, returning CID and full compound data. - summary: Get compound by SMILES method: GET path: /compound/smiles/{smiles}/JSON description: Retrieve compound records by canonical SMILES string. - summary: Get compound by InChI method: GET path: /compound/inchi/{inchi}/JSON description: Retrieve compound records by IUPAC International Chemical Identifier. - summary: Get compound properties method: GET path: /compound/cid/{cid}/property/{properties}/JSON description: Retrieve selected calculated properties (MolecularFormula, MolecularWeight, CanonicalSMILES, InChI, InChIKey, IUPACName, XLogP, TPSA, etc.) for a compound. - summary: Get compound synonyms method: GET path: /compound/cid/{cid}/synonyms/JSON description: Retrieve all synonyms and alternative names for a compound. - summary: Get compound SIDs method: GET path: /compound/cid/{cid}/sids/JSON description: Retrieve all substance IDs (SIDs) associated with a compound. - summary: Get compound cross-references method: GET path: /compound/cid/{cid}/xrefs/{xreftypes}/JSON description: Retrieve external cross-references (RegistryID, RN, PubMedID, MMDBID, ProteinGI, NucleotideGI, TaxonomyID, MIMID, GeneID, ProbeID, PatentID) for a compound. - summary: Get compound image method: GET path: /compound/cid/{cid}/PNG description: Retrieve a 2D structure image of a compound in PNG format. - summary: Get compound bioassay summary method: GET path: /compound/cid/{cid}/assaysummary/JSON description: Retrieve a summary of bioassay results for a compound, including activity outcomes and assay metadata. - summary: Substructure search method: GET path: /compound/substructure/smiles/{smiles}/JSON description: Search for compounds containing a specified substructure using SMILES, InChI, or SDF input. Returns async listkey for large result sets. - summary: Superstructure search method: GET path: /compound/superstructure/smiles/{smiles}/JSON description: Search for compounds that are superstructures of the specified structure. - summary: Similarity search method: GET path: /compound/fastsimilarity_2d/smiles/{smiles}/JSON description: Fast 2D Tanimoto similarity search for structurally similar compounds. - summary: Get substance by SID method: GET path: /substance/sid/{sid}/JSON description: Retrieve a substance record by PubChem Substance ID (SID), including source information, synonyms, and associated compound. - summary: Get substance synonyms method: GET path: /substance/sid/{sid}/synonyms/JSON description: Retrieve all synonyms for a substance record. - summary: Get assay by AID method: GET path: /assay/aid/{aid}/JSON description: Retrieve a full bioassay record by Assay ID (AID), including protocol, results schema, and experimental data. - summary: Get assay description method: GET path: /assay/aid/{aid}/description/JSON description: Retrieve descriptive metadata for a bioassay, including title, protocol, target information, and measurement parameters. - summary: Get assay results method: GET path: /assay/aid/{aid}/CSV description: Retrieve bioassay experimental results in CSV format with all tested substance outcomes and activity values. - summary: Retrieve async results by listkey method: GET path: /compound/listkey/{listkey}/cids/JSON description: Poll for and retrieve results from an asynchronous structure search query using the listkey returned during the search initiation. - name: PubChem PUG View API description: The PUG View API provides access to the full structured compound and substance pages as seen on the PubChem website, organized as hierarchical sections covering names, structures, physical and chemical properties, safety data, pharmacology, biological activities, toxicology, literature references, and more. humanURL: https://pubchem.ncbi.nlm.nih.gov/docs/pug-view baseURL: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view tags: - Compound Data - Safety Data - Pharmacology - Toxicology - Structured Data properties: - type: Documentation url: https://pubchem.ncbi.nlm.nih.gov/docs/pug-view contact: - FN: PubChem Help Desk email: pubchem-help@ncbi.nlm.nih.gov operations: - summary: Get full compound data page method: GET path: /data/compound/{cid}/JSON description: Retrieve all structured data for a compound as seen on its PubChem compound page, organized in hierarchical sections. - summary: Get compound data section method: GET path: /data/compound/{cid}/JSON description: Retrieve a specific section of a compound data page using the heading parameter (e.g., Safety+and+Hazards, Pharmacology+and+Biochemistry, Chemical+and+Physical+Properties). - summary: Get full substance data page method: GET path: /data/substance/{sid}/JSON description: Retrieve all structured data for a substance record in hierarchical section format. - summary: Get annotations by heading method: GET path: /annotations/heading/{heading}/JSON description: Retrieve annotations across all compounds for a specific data heading (e.g., Boiling+Point, LogP, Melting+Point). - summary: Get data in XML format method: GET path: /data/compound/{cid}/XML description: Retrieve full compound structured data in XML format. - summary: Get data in ASNT format method: GET path: /data/compound/{cid}/ASNT description: Retrieve full compound structured data in ASN.1 text format for programmatic parsing. - name: PubChem PUG SOAP API description: Legacy SOAP/XML web service interface for PubChem providing structure search, identity search, and chemical standardization capabilities. Supports submitting queries and retrieving results in ASN.1, XML, and SDF formats. humanURL: https://pubchem.ncbi.nlm.nih.gov/pug/pugsoap.cgi?wsdl baseURL: https://pubchem.ncbi.nlm.nih.gov/pug/pugsoap.cgi tags: - SOAP - Legacy - Structure Search - Chemical Standardization properties: - type: Documentation url: https://pubchem.ncbi.nlm.nih.gov/docs/pug-soap - type: WSDL url: https://pubchem.ncbi.nlm.nih.gov/pug/pugsoap.cgi?wsdl contact: - FN: PubChem Help Desk email: pubchem-help@ncbi.nlm.nih.gov - name: PubChem Structure Image Service description: Generates 2D and 3D structure images for chemical compounds by CID, SID, SMILES, or InChI. Returns PNG images at configurable sizes, suitable for embedding in applications and documents. humanURL: https://pubchem.ncbi.nlm.nih.gov/docs/pug-rest#section=PNG baseURL: https://pubchem.ncbi.nlm.nih.gov/rest/pug tags: - Structure Images - 2D Structures - Visualization properties: - type: Documentation url: https://pubchem.ncbi.nlm.nih.gov/docs/pug-rest#section=PNG contact: - FN: PubChem Help Desk email: pubchem-help@ncbi.nlm.nih.gov operations: - summary: Get compound 2D structure image by CID method: GET path: /compound/cid/{cid}/PNG description: Returns a PNG image of the 2D chemical structure for the given compound ID. Size can be controlled with the image_size parameter. - summary: Get compound image by name method: GET path: /compound/name/{name}/PNG description: Returns a PNG image of the 2D chemical structure for a compound looked up by name. - summary: Get compound image by SMILES method: GET path: /compound/smiles/{smiles}/PNG description: Returns a PNG image of the 2D chemical structure for the compound specified by SMILES string. - name: PubChem Identifier Exchange Service description: Bulk identifier conversion service for translating between PubChem CIDs, SIDs, and external identifiers such as CAS Registry Numbers, ChEMBL IDs, ChEBI IDs, and other registry identifiers at scale. humanURL: https://pubchem.ncbi.nlm.nih.gov/idexchange/idexchange.cgi baseURL: https://pubchem.ncbi.nlm.nih.gov/idexchange tags: - Identifier Conversion - CAS Numbers - ChEMBL - ChEBI - Registry IDs properties: - type: Documentation url: https://pubchem.ncbi.nlm.nih.gov/docs/identifier-exchange-service contact: - FN: PubChem Help Desk email: pubchem-help@ncbi.nlm.nih.gov common: - type: Terms of Service url: https://www.nlm.nih.gov/web_policies.html - type: Privacy Policy url: https://www.nlm.nih.gov/privacy.html - type: Status url: https://pubchem.ncbi.nlm.nih.gov/ - type: Support url: https://support.nlm.nih.gov/ - type: Sign Up url: https://www.ncbi.nlm.nih.gov/account/ - type: GitHub url: https://github.com/ncbi - type: Blog url: https://pubchemblog.wordpress.com/ - type: Documentation url: https://pubchem.ncbi.nlm.nih.gov/docs/ - type: FAQ url: https://pubchem.ncbi.nlm.nih.gov/docs/faq - type: Rate Limits url: https://pubchem.ncbi.nlm.nih.gov/docs/programmatic-access#section=Request-Volume-Limitations - type: Plans url: plans/plans.yml - type: Rate Limits url: rate-limits/rate-limits.yml - type: FinOps url: finops/finops.yml maintainers: - FN: Kin Lane email: kin@apievangelist.com