Reactome Content Service REST API

Base URL

https://reactome.org/ContentService

No authentication required. JSON by default.

Key Endpoints

Search (full-text across pathways, reactions, proteins)

GET /search/query?query={term}

Parameters:

• query (required) — search term (e.g. "apoptosis", "TP53", "R-HSA-109581")
• species — filter by species (e.g. "Homo sapiens")
• types — filter by type: Pathway, Reaction, Protein, Complex, SmallMolecule
• cluster — boolean, cluster results (default true)
• rows — page size
• Start row — offset for pagination

Example:

/search/query?query=apoptosis&species=Homo+sapiens&types=Pathway

Response:

{
  "results": [
    {
      "typeName": "Pathway",
      "rows": [
        {
          "dbId": 109581,
          "stId": "R-HSA-109581",
          "name": "Apoptosis",
          "species": ["Homo sapiens"],
          "summation": ["..."]
        }
      ]
    }
  ],
  "found": 42
}

Autocomplete

GET /search/suggest?query={partial_term}

Top-level pathways for a species

GET /data/pathways/top/{species}

Example: /data/pathways/top/Homo+sapiens

Pathway details

GET /data/query/{id}

Where {id} is a stable ID like R-HSA-109581 or a numeric dbId.

Events contained in a pathway

GET /data/pathway/{id}/containedEvents

Participants of a reaction

GET /data/event/{id}/participants

Ancestors of an event

GET /data/event/{id}/ancestors

Map external ID to pathways (e.g. UniProt to Reactome pathways)

GET /data/mapping/{resource}/{id}/pathways

Example — find pathways for TP53 (UniProt P04637):

/data/mapping/UniProt/P04637/pathways

Map external ID to reactions

GET /data/mapping/{resource}/{id}/reactions

Generic entity lookup

GET /data/query/{id}

Reference entities for an event

GET /data/participants/{id}/referenceEntities

All species

GET /data/species/all

Event hierarchy for a species (large response)

GET /data/eventsHierarchy/{species}

Stable ID Format

R-{species_code}-{number}

External Resource Names for Mapping

UniProt, ChEBI, ENSEMBL, miRBase, GeneCards, NCBI

Multiple values for same parameter: repeat the parameter (e.g. types=Pathway&types=Reaction).

Rate Limits

No API key required. No formal rate limit published, but be reasonable — avoid hundreds of concurrent requests. For bulk data, use Reactome's downloadable dumps (MySQL, Neo4j, BioPAX, SBML).