> ## Documentation Index
> Fetch the complete documentation index at: https://docs.catalog.igvf.org/llms.txt
> Use this file to discover all available pages before exploring further.

# API Introduction

> IGVF Catalog REST API — development environment

<Warning>
  This API reference documents the **development** Catalog API at `https://catalog-api-dev.demo.igvf.org/api`. The base URL will change when production is published; see [openapi/config.json](https://github.com/IGVF-DACC/igvf-catalog-docs/blob/main/openapi/config.json) in the repository.
</Warning>

# IGVF Catalog REST API

The IGVF Catalog exposes an OpenAPI-compliant REST API for querying the genomics knowledge graph: variants, genes, proteins, regulatory elements, QTLs, pathways, drugs, and more.

## Base URL

```
https://catalog-api-dev.demo.igvf.org/api
```

Interactive Swagger UI: [catalog-api-dev.demo.igvf.org](https://catalog-api-dev.demo.igvf.org/)

## Pagination

* **`page`** — 0-based page index (default `0`)
* **`limit`** — page size; maximum **500** on most endpoints

Example: `GET /variants?region=chr1:1157520-1158189&page=0`

## Coordinates

The database uses **0-based, half-open** genomic coordinates on **GRCh38** (human) and **GRCm39** (mouse).

## Query patterns

Most endpoints accept **one primary filter** plus optional refinements. Examples in each endpoint description are tested individually (see [audit results](https://github.com/IGVF-DACC/igvf-catalog-docs/tree/main/scripts)).

### Variant identifiers

Variants can be queried by any of:

| Parameter             | Example                            |
| --------------------- | ---------------------------------- |
| `variant_id` / `spdi` | `NC_000020.11:3658947:A:G`         |
| `hgvs`                | `NC_000020.11:g.3658948A>G`        |
| `rsid`                | `rs58658771`                       |
| `ca_id`               | `CA739473472`                      |
| `region`              | `chr1:1157520-1158189` (max 10 kb) |

### Dataset provenance (`files_fileset`)

Many edges are tagged with a **`files_fileset`** accession (e.g. `IGVFFI9602ILPC`, `ENCFF968BZL`) linking Catalog results to source files on the [IGVF Portal](https://data.igvf.org) or [ENCODE Portal](https://encodeproject.org). See [Data Sources](/data-sources/index) and [Field lineage](/data-sources/field-lineage/index) for file metadata and column-to-API field mappings.

## Related resources

* [IGVF Catalog MCP](https://github.com/IGVF-DACC/igvf-catalog-mcp) — higher-level graph queries for agents
* [Live Catalog UI](https://catalog.igvf.org)