# Update a function

`PATCH /projects/{project_id}/branches/{branch_id}/functions/{slug}beta`

Updates the function's mutable metadata — currently only the display `name`. A string sets the display name; `null` clears it, after which the function's `name` falls back to its slug. Leading and trailing whitespace is trimmed; a whitespace-only name is rejected. Acts only on a function owned by the branch: a slug that is only inherited from an ancestor branch returns 404 — rename it on the branch that owns it. Like every other change on a branch, a rename is isolated per branch: a branch forked before the rename keeps the name it had at fork time.

**Note**: This endpoint is currently in Beta.

[Markdown for AI context](/guides/apis-sdks-reference-api-functions-update-project-branch-function)

```bash title="REST API - curl"
curl "https://console.neon.tech/api/v2/projects/$PROJECT_ID/branches/$BRANCH_ID/functions/$SLUG" \
  -X PATCH \
  -H "Authorization: Bearer $NEON_API_KEY"
```

```typescript title="Also available in"
import { createNeonClient, raw } from '@neon/sdk';

const neon = createNeonClient({ apiKey: process.env.NEON_API_KEY });
const { data } = await raw.updateProjectBranchFunction({
  client: neon.client,
  path: {
    project_id: process.env.PROJECT_ID,
    branch_id: process.env.BRANCH_ID,
    slug: process.env.SLUG
  }
});
```

## Parameters

Project ID

`project_id`

string

The Neon project ID

Branch ID

`branch_id`

string

The Neon branch ID

Slug

`slug`

string

The function slug

## Request body

**1 required** Required: `name`.

Name

`name`

string

New display name for the function. `null` clears the display name; the function's `name` then falls back to its slug. Leading and trailing whitespace is trimmed; a whitespace-only name is rejected.

≥1 chars, ≤256 chars

## Response

200

The updated function

::::tabs
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Depth
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:::tab{title="example"}
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## Errors

default

General error

This endpoint can return the standard Neon API error response.

Response fields

- `message` Required. Human-readable error message.
- `code` Required. Machine-readable error code.
- `request_id` Optional. Request identifier for debugging. You can provide one with the `X-Request-ID` header.

Retry guidance

If no response is returned, the request may still have reached the server. This is why retry safety depends on the method and status code.

Idempotent methods (`GET`, `HEAD`, `OPTIONS`) are generally safe to retry after a network error or timeout. Non-idempotent methods (`POST`, `PATCH`, `DELETE`, `PUT`) can change state, so avoid automatic retries unless your workflow can tolerate duplicate effects.

Responses with `423 Locked` or `503 Service Unavailable` are safe to retry. `423 Locked` means the resource is temporarily locked, usually because another operation is in progress.

## Related pages

- [Create a trigger](./apis-sdks-reference-api-functions-create-project-branch-trigger.md)
- [Delete a custom domain from a branch](./apis-sdks-reference-api-functions-delete-project-branch-custom-domain.md)
- [Delete a function on the branch](./apis-sdks-reference-api-functions-delete-project-branch-function.md)
- [Delete a trigger](./apis-sdks-reference-api-functions-delete-project-branch-trigger.md)
- [Deploy code to a function](./apis-sdks-reference-api-functions-create-project-branch-function-deployment.md)
- [Get a trigger](./apis-sdks-reference-api-functions-get-project-branch-trigger.md)
- [Get function details](./apis-sdks-reference-api-functions-get-project-branch-function.md)
- [List functions on the branch](./apis-sdks-reference-api-functions-list-project-branch-functions.md)
- [List the custom domains on a branch](./apis-sdks-reference-api-functions-list-project-branch-custom-domains.md)
- [List triggers on the branch](./apis-sdks-reference-api-functions-list-project-branch-triggers.md)

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