# Protein Interactions API > Protein-protein interaction networks as an API — powered by STRING, the database of known and predicted protein associations that combines evidence from laboratory experiments, curated pathway databases, gene co-expression, genomic context and automated text mining into a single confidence score, across thousands of organisms. Get a protein's top interaction partners (each with the combined confidence score and the seven evidence-channel subscores), the interaction network among any set of proteins as scored edges, and functional enrichment for a gene set — the over-represented GO terms, KEGG pathways, Pfam domains and more, each with its p-value, FDR and member genes. Pass gene symbols (TP53) or STRING/Ensembl ids, for human (default) or any species by NCBI taxon id. It is a cornerstone of systems biology — ideal for network analysis, functional genomics, pathway and bioinformatics tools. A protein-interaction-network resource — distinct from biological pathways (Reactome), curated protein complexes (Complex Portal) and Gene Ontology annotations (QuickGO). Open data from STRING (CC BY 4.0). ## Authentication All requests require your oanor API key in the `x-oanor-key` header. Get one at https://www.oanor.com/developer/keys. ```bash curl -H "x-oanor-key: oanor_live_…" "https://api.oanor.com/stringdb-api/..." ``` ## Pricing - **Free** (Free) — 2,650 calls/Mo, 2 req/s - **Starter** ($7/Mo) — 52,500 calls/Mo, 8 req/s - **Pro** ($23/Mo) — 252,000 calls/Mo, 20 req/s - **Mega** ($60/Mo) — 895,000 calls/Mo, 50 req/s ## Endpoints ### Protein Interactions #### `GET /v1/enrichment` — Functional enrichment for a gene set **Parameters:** - `proteins` (query, optional, string) — Comma-separated proteins (2-100) Example: `TP53,MDM2,EP300,CDKN1A` - `species` (query, optional, string) — NCBI taxon id (default 9606) Example: `9606` - `category` (query, optional, string) — Optional category filter (Process, KEGG, …) **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/stringdb-api/v1/enrichment?proteins=TP53%2CMDM2%2CEP300%2CCDKN1A&species=9606" ``` **Response:** ```json { "data": { "count": 50, "terms": [ { "fdr": 0.0266, "term": "GOCC:0005654", "genes": [ "MDM2", "EP300", "TP53", "CDKN1A" ], "p_value": 1.15e-5, "category": "COMPARTMENTS", "description": "Nucleoplasm", "genes_in_set": 4, "genes_in_background": 1146 }, { "fdr": 8.66e-6, "term": "GO:0072331", "genes": [ "MDM2", "EP300", "TP53", "CDKN1A" ], "p_value": 5.52e-10, "category": "Process", "description": "Signal transduction by p53 class mediator", "genes_in_set": 4, "genes_in_background": 93 }, { "fdr": 4.35e-5, "term": "GO:0006977", "genes": [ "MDM2", "TP53", "CDKN1A" ], "p_value": 5.55e-9, "category": "Process", "description": "DNA damage response, signal transduction by p53 class mediator resulting in cell cycle arrest", "genes_in_set": 3, "genes_in_background": …(truncated, see openapi.json for full schema) ``` #### `GET /v1/network` — Interactions among a set of proteins **Parameters:** - `proteins` (query, optional, string) — Comma-separated proteins (2-100) Example: `TP53,MDM2,EP300` - `species` (query, optional, string) — NCBI taxon id (default 9606) Example: `9606` **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/stringdb-api/v1/network?proteins=TP53%2CMDM2%2CEP300&species=9606" ``` **Response:** ```json { "data": { "edges": [ { "channels": { "fusion": 0, "database": 0, "textmining": 0.994, "coexpression": 0.152, "cooccurrence": 0, "experimental": 0.82, "neighborhood": 0 }, "protein_a": "MDM2", "protein_b": "EP300", "string_id_a": "9606.ENSP00000258149", "string_id_b": "9606.ENSP00000263253", "combined_score": 0.999 }, { "channels": { "fusion": 0, "database": 0.9, "textmining": 0.999, "coexpression": 0.116, "cooccurrence": 0, "experimental": 0.999, "neighborhood": 0 }, "protein_a": "MDM2", "protein_b": "TP53", "string_id_a": "9606.ENSP00000258149", "string_id_b": "9606.ENSP00000269305", "combined_score": 0.999 }, { "channels": { "fusion": 0, "database": 0.9, "textmining": 0.998, "coexpression": 0.049, "cooccurrence": 0, "experimental": 0.999, "neighborhood": …(truncated, see openapi.json for full schema) ``` #### `GET /v1/partners` — A protein's interaction partners **Parameters:** - `protein` (query, optional, string) — Gene symbol or STRING/Ensembl id Example: `TP53` - `species` (query, optional, string) — NCBI taxon id (default 9606) Example: `9606` - `limit` (query, optional, string) — Max partners (1-100, default 25) **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/stringdb-api/v1/partners?protein=TP53&species=9606" ``` **Response:** ```json { "data": { "count": 25, "protein": "TP53", "species": "9606", "partners": [ { "channels": { "fusion": 0, "database": 0.75, "textmining": 0.859, "coexpression": 0, "cooccurrence": 0, "experimental": 0.981, "neighborhood": 0 }, "protein_a": "TP53", "protein_b": "SFN", "string_id_a": "9606.ENSP00000269305", "string_id_b": "9606.ENSP00000340989", "combined_score": 0.999 }, { "channels": { "fusion": 0, "database": 0.9, "textmining": 0.998, "coexpression": 0.049, "cooccurrence": 0, "experimental": 0.999, "neighborhood": 0 }, "protein_a": "TP53", "protein_b": "EP300", "string_id_a": "9606.ENSP00000269305", "string_id_b": "9606.ENSP00000263253", "combined_score": 0.999 }, { "channels": { "fusion": 0, "database": 0, "textmining": 0.994, "coexpression": 0, "cooccurrence": 0, …(truncated, see openapi.json for full schema) ``` ### Meta #### `GET /v1/meta` — Endpoint catalogue & notes **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/stringdb-api/v1/meta" ``` **Response:** ```json { "data": { "note": "STRING is a database of known and predicted protein–protein interactions, combining evidence from experiments, curated pathway databases, co-expression, genomic context and automated text mining into confidence-scored networks across thousands of organisms. /v1/partners?protein=TP53&species=9606 = a protein's top interaction partners (species is an NCBI taxon id, default 9606 = human), each with the combined confidence score (0–1) and the seven evidence-channel subscores (neighborhood, fusion, cooccurrence, coexpression, experimental, database, textmining); /v1/network?proteins=TP53,MDM2,EP300&species=9606 = the interactions among a set of proteins (2–100) as scored edges; /v1/enrichment?proteins=TP53,MDM2,EP300,CDKN1A&species=9606 = functional enrichment of a gene set — over-represented GO terms, KEGG pathways, Pfam domains and more, each with its p-value, FDR and member genes (optionally filter by category). Protein identifiers can be gene symbols (TP53) or STRING/Ensembl ids. Data from STRING (CC BY 4.0). A protein-interaction-network resource — distinct from pathways (Reactome), curated complexes (Complex Portal) and GO annotations (QuickGO). Ideal for systems biology, network analysis, functional genomics and bioinformatics tools.", "source": "STRING — protein–protein interaction networks (string-db.org)", "channels": { "fusion": "gene fusion", "database": "curated databases", …(truncated, see openapi.json for full schema) ``` --- Marketplace page: https://www.oanor.com/api/stringdb-api OpenAPI spec: https://www.oanor.com/api/stringdb-api/openapi.json