Curated pathway database website, reactions, diagrams, analysis, APIs

Reactome

Reactome is a curated pathway database website for exploring biological reactions, pathways, diagrams, pathway analysis tools, downloads, and programmatic data access.

Official site

reactome.org is the main public website for Reactome.

Database focus

Reactome focuses on curated pathways, reactions, pathway diagrams, molecular participants, analysis tools, downloads, and APIs.

Interpretation caution

Pathway diagrams and enrichment results are research aids, not complete causal models of a biological system.

The Reactome logo.View logo on Reactome

What Reactome is

Reactome is a curated pathway database website at reactome.org for exploring biological reactions, pathways, pathway diagrams, analysis tools, downloads, and APIs. It focuses on human biology while also supporting species comparison and inferred pathway information for other organisms.

Pathways and reactions

Reactome represents biology as pathways made from reactions and molecular events. A pathway can describe processes such as metabolism, signaling, immune response, DNA repair, gene expression, cell cycle regulation, and many other systems where molecules interact over time.

Pathway Browser

The Pathway Browser is the main visual interface for navigating Reactome. It lets users move through pathway hierarchies, open diagrams, inspect reaction participants, search molecules, view details, and connect a high-level pathway overview to specific molecular events.

Pathway analysis

Reactome analysis tools can map submitted identifiers onto pathways and support enrichment-style interpretation of gene, protein, or other molecular lists. These results are useful for exploring patterns in omics data, but they still need biological judgment, background choices, and follow-up evidence.

Curation and cross-references

Reactome's records are curated and linked to external resources such as UniProt, Gene Ontology, Ensembl, literature references, and other biological databases. Those links help users move from a pathway diagram to protein details, gene identifiers, functional terms, and source evidence.

Downloads and APIs

The website provides downloadable data and a Content Service API for programmatic access. Developers and researchers can use these services to retrieve pathway content, build reproducible pipelines, integrate pathway knowledge into software, or connect Reactome with local analysis systems.

Strengths and limits

Reactome is strong because it makes pathway knowledge searchable, visual, and reusable, but pathway boundaries are human-made abstractions. Biological processes can be context-specific, incomplete, tissue-dependent, species-dependent, or revised as new evidence changes how a pathway is understood.

Why it matters

Reactome matters because pathways connect genes, proteins, small molecules, reactions, disease biology, and experimental datasets. A public pathway website helps researchers and students turn lists of molecules into structured biological questions rather than isolated names.

WHOIS domain data

Data pulled: June 1, 2026View current WHOIS record

Domain: reactome.org
IP address: 100.25.71.177
Registrar: easyDNS Technologies Inc.
WHOIS server: whois.easydns.com
Referral URL: http://www.easydns.com
Created: April 27, 2004
Updated: May 26, 2026
Expires: April 27, 2027
Nameservers: ishaan.ns.cloudflare.com (162.159.44.213); oaklyn.ns.cloudflare.com (108.162.194.90)
Domain status: ok
Registrant organization: Ontario Institute for Cancer Research
Contact privacy: Registrant address, phone, fax, and email are redacted for privacy in the Who.is record.

Key concepts

biological pathway
reaction
pathway browser
curated database
pathway analysis
molecular event
downloadable data
content service API

Common use cases

browsing human biological pathways
viewing pathway diagrams and reaction details
mapping gene or protein lists onto pathways
running pathway enrichment analysis
downloading pathway data for research
using Reactome APIs in software workflows
connecting pathway knowledge with UniProt, GO, Ensembl, and literature records

Common misconceptions

A pathway diagram is a complete model of every cellular event.
Reactome contains every pathway known in biology.
Pathway enrichment results prove causation by themselves.
Programmatic access removes the need to understand pathway curation and data models.

Open questions

How should pathway databases represent uncertain or context-specific biology?
Which visualizations help users read large pathway networks without oversimplifying them?
How can curated pathway records stay connected to fast-moving literature and omics datasets?
What metadata best explains species inference, evidence, reaction participants, and pathway boundaries?