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    /APIs & SDKs/Functions/Register a custom domain on a branch
    POST/projects/{project_id}/branches/{branch_id}/custom-domainsbeta

    Register a custom domain on a branch

    Registers a customer-owned domain (for example dashboard.acme.com) on the branch and points it at a target entity, chosen by entity_type + entity_id. In v1 only entity_type: function is supported (an unsupported type is rejected with 400), where entity_id is the function slug and the function must already exist on the branch (else 404).

    The response includes the cname_target the customer must point their domain at with a CNAME record; the domain goes live only once that DNS resolves and a certificate is issued on the first request. A domain already registered to another resource is rejected with 409 and no detail about the owner. Re-registering the same domain for the same entity is idempotent.

    Note: This endpoint is currently in Beta.

    Markdown for AI context

    Quick start

    REST API - curl
    curl "https://console.neon.tech/api/v2/projects/$PROJECT_ID/branches/$BRANCH_ID/custom-domains" \
  -X POST \
  -H "Authorization: Bearer $NEON_API_KEY"
    Also available in
    import { createNeonClient, raw } from '@neon/sdk';

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

    Parameters

    Project ID
    project_id
    string

    The Neon project ID

    Branch ID
    branch_id
    string

    The Neon branch ID

    Request body

    3 required Required: domain, entity_type, entity_id.

    Domain
    domain
    string

    The custom domain to register (for example dashboard.acme.com). Case-insensitive; normalized to lowercase (a trailing root dot is stripped, so the 254-char bound admits a fully-qualified name whose normalized form is 253 chars). Neon-managed and internal hostnames are rejected.

    ≥3 chars, ≤254 chars

    Entity type
    entity_type
    string

    The kind of branch entity to point the domain at. v1 supports only function; any other value is rejected with invalid_entity_type.

    ≥1 chars, ≤32 chars

    Entity ID
    entity_id
    string

    The target entity's identifier within the branch. For function this is the function slug (which must already exist on the branch).

    ≥1 chars, ≤255 chars

    Response

    201

    The registered custom domain

    Depth
    "domain": (string),req
    "entity_type": (string),req
    "entity_id": (string),req
    "cname_target": (string),req
    "status": (string),
    "dns_status": (string),
    "binding_status": (string),
    "status_reason": (string),

    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.

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