# Catchment API

> Reference for postcode catchment, H3 cell and local-authority metrics, area mappings and API trial credits.

- [Overview](https://docs.catchment.app/index.md): Endpoint, authentication, response, credit and coverage reference for the Catchment API.
- [Get catchment metrics](https://docs.catchment.app/api-reference/catchments/get-catchment-metrics.md): Requested catchment metrics and, when selected, separate local-authority fee/occupancy values for the postcode. Supply exactly one of drive_minutes or radius_miles. The request reserves the number of unique metrics; successful non-null values consume one credit each.
- [Get hex metrics](https://docs.catchment.app/api-reference/cells/get-hex-metrics.md): Metric values for one H3 resolution-8 cell. Only keys supporting hex are accepted. Care supply, planning and authority metrics are not supported at this endpoint. Successful non-null requested values consume one credit each.
- [Get local authority metrics](https://docs.catchment.app/api-reference/local-authorities/get-local-authority-metrics.md): Requested fee and occupancy values for an ONS district, county or unitary authority code. Districts resolve to their social-care parent authority. No radius or projection year is accepted.
- [List cells for an area](https://docs.catchment.app/api-reference/area-mappings/list-cells-for-an-area.md): Returns the H3 cells an area overlaps, with the share of the area in each cell and the share of each cell the area covers. Cells are ordered by `share_of_area`, largest first. This endpoint uses no credits.
- [List areas for a cell](https://docs.catchment.app/api-reference/area-mappings/list-areas-for-a-cell.md): Returns the areas of one type that overlap an H3 cell, with the share of each area in the cell and the share of the cell each area covers. Areas are ordered by `share_of_cell`, largest first. This endpoint uses no credits.
- [List metrics](https://docs.catchment.app/api-reference/metrics/list-metrics.md): Catalogue of metrics this organisation can request, with stable key, label, description, unit, domain, source, nation coverage, supported geographies and period basis. Query parameters are ignored. This endpoint uses no credits.
- [Metric catalogue](https://docs.catchment.app/api-reference/metric-catalogue.md): Current metric keys, units, geographies, projection, nation scope and sources.

## OpenAPI Specs

- [openapi](/api-reference/openapi.json)


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