---
title: "Expand a concept or collection to all it's narrower concepts."
method: GET
path: "/conceptschemes/{scheme_id}/c/{c_id}/expand"
tags: ["Pyramid_skosprovider"]
---

# Expand a concept or collection to all it's narrower concepts.

`GET /conceptschemes/{scheme_id}/c/{c_id}/expand`

## Request

- Base URL: `/` (relative, and the document was published on a file host, not at the API’s origin)
- URL: `/conceptschemes/{scheme_id}/c/{c_id}/expand`
- Auth: none declared
- TypeScript: <https://skmtc.dev/onroerenderfgoed/apis/atramhasis-api/docs/conceptschemes/:scheme_id/c/:c_id/expand/get.ts> (a function with typed inputs; its response is checked against the schema)

Expand a concept or collection to all it's narrower concepts.
This method should recurse and also return narrower concepts of narrower concepts.
If the id passed belongs to a :class:`skosprovider.skos.Concept`, the id of the concept itself should be include in the return value.
If the id passed belongs to a :class:`skosprovider.skos.Collection`, the id of the collection itself must not be present in the return value In this case the return value includes all the member concepts and their narrower concepts.
Returns A list of id's or :class:`HTTPNotFound` if the concept or collection doesn't exist.

## Path parameters

- `scheme_id` string, required
- `c_id` string, required

## Response `200`

The concept/collection was found in the conceptscheme.

- string[]

## Other responses

- `404`: The concept/collection was not found in the conceptscheme or the conceptscheme was not found.

## Changes

- **2025-11-20** `d98571488187`: 1 breaking
  - the `items/` response's property type changed from `integer` to `string` for status `200`
- **2024-08-01** `20edc4da41fd`: 1 info
  - for the `path` request parameter `c_id`, the type was generalized from `integer` to `string`
- **2021-12-22** `042de7aa8903`: 1 info
  - endpoint added
- **2021-12-20** `720170256c20`: 1 breaking
  - api path removed without deprecation

[Operation history](https://skmtc.dev/onroerenderfgoed/apis/atramhasis-api/changes/conceptschemes/:scheme_id/c/:c_id/expand/get.md)

---

[API](https://skmtc.dev/onroerenderfgoed/apis/atramhasis-api.md) - [All operations](https://skmtc.dev/onroerenderfgoed/apis/atramhasis-api/llms.txt) - [OpenAPI document](https://skmtc.dev/onroerenderfgoed/apis/atramhasis-api/revisions/c2d0b54078a2?raw)