# EMDB API
> The Electron Microscopy Data Bank (EMDB) as an API, powered by EMBL-EBI — the public archive of three-dimensional electron-microscopy density maps of proteins, nucleic acids and large macromolecular complexes. EMDB is the electron-microscopy counterpart of the Protein Data Bank, holding maps solved by single-particle cryo-EM, electron tomography and electron crystallography, the technique behind the recent "resolution revolution" in structural biology. /v1/search?q=ribosome searches the archive and returns each matching entry's EMDB id (e.g. EMD-1010), title, electron-microscopy method and resolution in ångström. /v1/entry?id=EMD-1010 returns an entry's metadata — its title, the EM method (single particle, tomography, …), the aggregation state, the resolution, the biological sample studied, classification keywords, the deposition, map-release and last-update dates, and the depositing authors. EMDB ids look like EMD-1010, and you may pass just the number. Ideal for structural-biology and cryo-EM tools, structure-comparison and visualisation apps, and education. Data from EMBL-EBI EMDB (public domain). This is the archive of experimental electron-microscopy MAPS — distinct from atomic-coordinate structures (the PDB), predicted structures (AlphaFold) and protein-sequence databases (UniProt).

## 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/emdb-api/..."
```

## Pricing
- **Free** (Free) — 2,300 calls/Mo, 2 req/s
- **Starter** ($7/Mo) — 49,000 calls/Mo, 5 req/s
- **Pro** ($21/Mo) — 215,000 calls/Mo, 12 req/s
- **Mega** ($58/Mo) — 790,000 calls/Mo, 35 req/s

## Endpoints

### Maps

#### `GET /v1/entry` — An EM entry metadata

**Parameters:**
- `id` (query, required, string) — EMDB id, e.g. EMD-1010 Example: `EMD-1010`

**Example:**
```bash
curl -H "x-oanor-key: $KEY" \
  "https://api.oanor.com/emdb-api/v1/entry?id=EMD-1010"
```

**Response:**
```json
{
    "data": {
        "entry": {
            "url": "https://www.ebi.ac.uk/emdb/EMD-1010",
            "title": "A cryo-electron microscopic study of ribosome-bound termination factor RF2.",
            "method": "singleParticle",
            "sample": "RF2(GGQ) wild type from E.coli",
            "authors": [
                "Rawat UB",
                "Zavialov AV",
                "Sengupta J",
                "Valle M",
                "Grassucci RA",
                "Linde J",
                "Vestergaard B",
                "Ehrenberg M",
                "Frank J"
            ],
            "emdb_id": "EMD-1010",
            "keywords": "\n         ",
            "last_update": "2013-12-25",
            "deposition_date": "2002-09-26",
            "map_release_date": "2003-09-26",
            "aggregation_state": "particle",
            "resolution_angstrom": 12.9
        }
    },
    "meta": {
        "timestamp": "2026-06-01T16:23:19.039Z",
        "request_id": "bba5d64c-3a55-4eaf-9b94-8ec5b4518afc"
    },
    "status": "ok",
    "message": "Entry retrieved",
    "success": true
}
```

#### `GET /v1/search` — Search the EM archive

**Parameters:**
- `q` (query, required, string) — Search text, e.g. ribosome Example: `ribosome`
- `limit` (query, optional, string) — Max results (1-25)

**Example:**
```bash
curl -H "x-oanor-key: $KEY" \
  "https://api.oanor.com/emdb-api/v1/search?q=ribosome"
```

**Response:**
```json
{
    "data": {
        "count": 10,
        "query": "ribosome",
        "entries": [
            {
                "title": "Manikomycin bound to the Escherichia coli 70S ribosome",
                "method": "singleParticle",
                "emdb_id": "EMD-54009",
                "resolution_angstrom": 2.45
            },
            {
                "title": "Cryo-EM structure of P. urativorans 70S ribosome after 2h acute stress - State 1: Rotated with E-tRNA/P-tRNA",
                "method": "singleParticle",
                "emdb_id": "EMD-57867",
                "resolution_angstrom": 3.08
            },
            {
                "title": "Cryo-EM structure of P. urativorans 70S ribosome after 2h acute stress - State 4: E-tRNA/RaiA/Balon",
                "method": "singleParticle",
                "emdb_id": "EMD-57870",
                "resolution_angstrom": 2.59
            },
            {
                "title": "E. coli 70S ribosome with peptidyl-tRNA, mRNA and Hsp15",
                "method": "singleParticle",
                "emdb_id": "EMD-57974",
                "resolution_angstrom": 2.78
            },
            {
                "title": "E. coli 70S ribosome with peptidyl-tRNA and Hsp15",
                "method": "singleParticle",
                "emdb_id": "EMD-57975",
                "resolution_angstrom": 2.92
            },
            {
                "title": "EMCV IRES captured on mammalian 40S with initiator tRNA",
                "met
…(truncated, see openapi.json for full schema)
```

### Meta

#### `GET /v1/meta` — Usage notes

**Example:**
```bash
curl -H "x-oanor-key: $KEY" \
  "https://api.oanor.com/emdb-api/v1/meta"
```

**Response:**
```json
{
    "data": {
        "note": "EMDB (the Electron Microscopy Data Bank) is the public archive of 3D electron-microscopy density maps of proteins, nucleic acids and large complexes — solved by single-particle cryo-EM, electron tomography and electron crystallography. It is the EM counterpart of the PDB. /v1/search?q=ribosome = search the archive (limit 1-25), returning each entry's EMDB id (e.g. EMD-1010), title, EM method and resolution; /v1/entry?id=EMD-1010 = an entry's metadata — title, method (single particle, tomography, …), aggregation state, resolution in ångström, the sample studied, keywords, deposition/release/update dates and authors. EMDB ids look like EMD-1010 (you may pass just the number). Data from EMBL-EBI EMDB (public domain). This is the archive of experimental electron-microscopy MAPS — distinct from atomic-coordinate structures (PDB), predicted structures (AlphaFold) and sequence databases. Ideal for structural biology, cryo-EM workflows and education.",
        "source": "EMDB — Electron Microscopy Data Bank, EMBL-EBI (ebi.ac.uk/emdb)",
        "endpoints": [
            "/v1/search",
            "/v1/entry",
            "/v1/meta"
        ]
    },
    "meta": {
        "timestamp": "2026-06-01T16:23:19.374Z",
        "request_id": "e00390e4-4995-4403-a2ed-04bf452e631a"
    },
    "status": "ok",
    "message": "Meta retrieved",
    "success": true
}
```


---
Marketplace page: https://www.oanor.com/api/emdb-api
OpenAPI spec: https://www.oanor.com/api/emdb-api/openapi.json