PubChem website screenshot

PubChem

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.

PubChem publishes 3 APIs on the APIs.io network: Compounds API, Structure Search API, and Utilities API. Tagged areas include Chemistry, Chemical Compounds, Drug Discovery, Bioassay, and Life Sciences.

The PubChem catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

PubChem’s developer surface includes status page, support, signup flow, GitHub presence, engineering blog, documentation, FAQ, and 8 more developer resources.

44.6/100 developing ▼ -5.4 Agent 28/100 agent aware Full breakdown ↓
scored 2026-07-28 · rubric v0.6
7 APIs
ChemistryChemical CompoundsDrug DiscoveryBioassayLife SciencesNCBIBioinformatics

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-07-28 · rubric v0.6
Composite quality — 44.6/100 · developing
Contract Quality 15.3 / 25
Developer Ergonomics 3.0 / 20
Commercial Clarity 10.0 / 20
Operational Transparency 4.8 / 13
Governance 7.0 / 12
Discoverability 8.2 / 10
Agent readiness — 28/100 · agent aware
Machine-Readable Contract 18 / 18
Agentic Access Contract 10 / 10
MCP Server 0 / 12
Machine-Readable Auth 0 / 10
Idempotency 0 / 9
Stable Error Semantics 0 / 8
Request/Response Examples 7 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 0 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3
A2A Agent Card 0 / 8
Dry-Run / Simulate Mode 0 / 4
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/pubchem: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 7

Individual APIs this provider publishes, each with its own machine-readable definition.

PubChem PUG View API

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, structure...

PubChem PUG SOAP API

Legacy SOAP/XML web service interface for PubChem providing structure search, identity search, and chemical standardization capabilities. Supports submitting queries and retriev...

PubChem Structure Image Service

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 d...

PubChem Identifier Exchange Service

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 i...

PubChem Compounds API

Operations on compound records

PubChem Structure Search API

Chemical structure search operations

PubChem Utilities API

Utility operations

Scroll for all 7

Pricing Plans 1

Published pricing tiers and plan structures.

Plans

2 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Rate Limits

4 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Finops

FINOPS

Semantic Vocabularies 1

JSON-LD contexts and semantic vocabularies used across these APIs.

Pubchem Context

21 classes · 0 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

PubChem API Rules

5 rules · 4 warnings 1 info

SPECTRAL

JSON Schema 1

Standalone JSON Schema definitions for this provider's data models.

PubChem Compound Properties

1 properties

JSON SCHEMA

Examples 4

Example request and response payloads for these APIs.

Get Compound By Cid

4 fields

EXAMPLE

Get Compound By Name

4 fields

EXAMPLE

Get Compound Synonyms

4 fields

EXAMPLE

Substructure Search

4 fields

EXAMPLE

Security Posture 1

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Pubchem Domain Security

TLSv1.3 · HSTS · DNSSEC · DMARC

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Pubchem Agentic Access

12 operations

12 operations · 0 acting

AGENTIC

Resources

Get Started 1

Portal, sign-up, and the first successful call

Documentation 1

Reference material describing how the API behaves

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

Build 1

SDKs, sample code, and the tooling you integrate with

Access & Security 1

Authentication, authorization, and security posture

Operate 5

Status, limits, changes, and where to get help

Commercial 4

Pricing, plans, and the legal terms of use

Company 1

The organization behind the API

Source (apis.yml)

apis.yml Raw ↑
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.
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - plans
  generated: '2026-07-22'
  method: derived
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 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
- aid: pubchem:pubchem-compounds-api
  name: PubChem Compounds API
  description: Operations on compound records
  humanURL: https://pubchem.ncbi.nlm.nih.gov/docs/pug-rest
  baseURL: https://pubchem.ncbi.nlm.nih.gov/rest/pug
  tags:
  - Compounds
  properties:
  - type: OpenAPI
    url: openapi/pubchem-compounds-api-openapi.yml
  - type: Documentation
    url: https://pubchem.ncbi.nlm.nih.gov/docs/pug-rest
- aid: pubchem:pubchem-structure-search-api
  name: PubChem Structure Search API
  description: Chemical structure search operations
  humanURL: https://pubchem.ncbi.nlm.nih.gov/docs/pug-rest
  baseURL: https://pubchem.ncbi.nlm.nih.gov/rest/pug
  tags:
  - Structure Search
  properties:
  - type: OpenAPI
    url: openapi/pubchem-structure-search-api-openapi.yml
  - type: Documentation
    url: https://pubchem.ncbi.nlm.nih.gov/docs/pug-rest
- aid: pubchem:pubchem-utilities-api
  name: PubChem Utilities API
  description: Utility operations
  humanURL: https://pubchem.ncbi.nlm.nih.gov/docs/pug-rest
  baseURL: https://pubchem.ncbi.nlm.nih.gov/rest/pug
  tags:
  - Utilities
  properties:
  - type: OpenAPI
    url: openapi/pubchem-utilities-api-openapi.yml
  - type: Documentation
    url: https://pubchem.ncbi.nlm.nih.gov/docs/pug-rest
common:
- type: AgenticAccess
  url: agentic-access/pubchem-agentic-access.yml
- type: DomainSecurity
  url: security/pubchem-domain-security.yml
- type: TermsOfService
  url: https://www.nlm.nih.gov/web_policies.html
- type: PrivacyPolicy
  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: Signup
  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: RateLimits
  url: https://pubchem.ncbi.nlm.nih.gov/docs/programmatic-access#section=Request-Volume-Limitations
- type: Plans
  url: plans/plans.yml
- type: RateLimits
  url: rate-limits/rate-limits.yml
- type: FinOps
  url: finops/finops.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com