---
title: "Assign an eSIM to a person"
method: POST
path: "/v1/esim/sims/{esim_id}/assignment"
tags: ["esims"]
---

# Assign an eSIM to a person

`POST /v1/esim/sims/{esim_id}/assignment`

## Request

- Base URL: `https://us1.platform.bird.com`
- URL: `https://us1.platform.bird.com/v1/esim/sims/{esim_id}/assignment`
- Auth: one of:
  - HTTP bearer
  - API key in cookie `bird_session`

Assigns an existing, allocated eSIM to a subscriber in the same workspace. Unavailable profile states return 409. Identification guidance does not gate assignment; customers handle identification collection and compliance. Repeating the same assignment returns its existing record; assigning a different person returns 409. This does not change paid packages, deliver credentials, or grant access to them.

## Headers

- `Idempotency-Key` string
- `X-Workspace-Id` string
- `X-Organization-Id` string

## Request body

- EsimAssignmentCreate: Assign an unassigned eSIM to this person. The profile must be allocated and ready, active, or suspended. Customers handle identification collection and compliance.
  - `subscriber_id` string, required

## Response `200`

The requested resource.

- EsimAssignment: The person assigned to one eSIM. Assignment grants no workspace membership or permission to read installation credentials.
  - `id` string, required
  - `subscriber_id` string, required
  - `esim_id` string, required
  - `created_at` string, date-time, required
  - `updated_at` string, date-time, required

## Other responses

- `400`: Bad request
- `401`: Authentication required
- `403`: Insufficient permissions
- `404`: Resource not found
- `409`: Resource conflict
- `422`: The request has invalid field values, violates a business rule, or carries a query parameter the endpoint does not declare. Field validation errors use `type: validation_error` and include the affected fields in `details`. Business-rule errors identify the failed rule in `type`.
- `429`: Rate limit exceeded
- `500`: Internal server error
- `503`: The service is temporarily unavailable. If `Retry-After` is present, wait for that delay before retrying; otherwise, retry with exponential backoff. Reuse the same idempotency key and request when retrying a mutation.

---

[API](https://skmtc.dev/messagebird/apis/bird-api.md) · [All operations](https://skmtc.dev/messagebird/apis/bird-api/llms.txt) · [OpenAPI document](https://skmtc.dev/messagebird/apis/bird-api/revisions/6dfce1179799?raw)