GET /uniref/search

uniprot.org:uniprot-api

Summary: Search UniRef clusters
Operation ID: searchUniRef
Auth: none

Search the UniProt Reference Clusters (UniRef) for protein clusters. UniRef groups similar protein sequences into clusters to speed up searches and reduce redundancy. Three cluster types exist: UniRef100 (identical sequences), UniRef90 (sequences with >=90% identity), and UniRef50 (sequences with >=50% identity). Use this endpoint when you want to work with protein clusters rather than individual entries. Each cluster has a representative member sequence, and cluster entries include the member count and organism diversity. This is useful for reducing redundancy in large-scale analyses or for finding protein families across different species.

Original spec description

Search UniProt Reference Clusters (UniRef) which cluster sequences at 100%, 90%, and 50% identity levels.

Usage Tips

- UniRef cluster IDs look like UniRef100_P01308 or UniRef90_A0A5E4NKF1 - Three cluster types: UniRef100 (100% identical), UniRef90 (90%+ similar), UniRef50 (50%+ similar) - Larger clusters (UniRef50) group more divergent sequences; smaller clusters (UniRef100) are more specific - `memberCount` shows how many sequences are in the cluster - `organismCount` shows how many different species are represented - The representative member provides the cluster name and representative sequence - Use UniRef for protein family analysis and reducing redundancy in datasets

Parameters (3)

format (string, query, optional, default: json)

Constraints: {'enum': ['json', 'xml']}

query (string, query, required)

Search query string

size (integer, query, optional, default: 25)

Examples (3)

TitleTypeURLAction
Search for insulin-related clusters curl https://rest.uniprot.org/uniref/search?query=insulin
Search for human proteins with limited results curl https://rest.uniprot.org/uniref/search?query=human&size=10
Search for specific organism by taxonomy ID curl https://rest.uniprot.org/uniref/search?query=taxonomy_id:9606&format=json

Probe History

Latency

Status Codes

TimeStatusLatencySize
2026-03-23 10:13:49.048496 200 140ms
2026-03-23 09:23:32.856486 200 132ms
2026-03-23 09:03:01.719172 200 140ms

Response Changes

WhenOldNew
2026-03-23 09:23:32.856486 4dafbb9ec4c4 1919e34d1339
2026-03-23 10:13:49.048496 1919e34d1339 81168e88dc5c