---
title: "Pair API user"
method: PUT
path: "/cosigners/{cosignerId}/api_users/{apiUserId}"
tags: ["Cosigners"]
---

# Pair API user

`PUT /cosigners/{cosignerId}/api_users/{apiUserId}`

## Request

- Base URL: `https://api.fireblocks.io/v1`
- URL: `https://api.fireblocks.io/v1/cosigners/{cosignerId}/api_users/{apiUserId}`
- Auth: none declared
- TypeScript: <https://skmtc.dev/fireblocks/apis/fireblocks-api/docs/cosigners/:cosignerId/api_users/:apiUserId/put.ts> (a function with typed inputs; its response is checked against the schema)

Pair an API user to a cosigner
Endpoint Permission: Admin and Non-Signing Admin.

## Path parameters

- `cosignerId` string, uuid, required
- `apiUserId` string, required

## Headers

- `Idempotency-Key` string

## Request body

- PairApiUserRequest
  - `callbackHandler` CallbackHandlerRequest
    - `url` string, required: The callback handler's URL
    - `publicKey` string: The callback handler's public key
    - `cert` string: The callback handler's certificate

## Response `202`

The API user object to be paired

- PairApiUserResponse
  - `id` string, uuid, required: The unique identifier of the API user
  - `callbackHandler` CallbackHandlerRequest
    - `url` string, required: The callback handler's URL
    - `publicKey` string: The callback handler's public key
    - `cert` string: The callback handler's certificate

## Other responses

- `default`: Error Response

---

[API](https://skmtc.dev/fireblocks/apis/fireblocks-api.md) - [All operations](https://skmtc.dev/fireblocks/apis/fireblocks-api/llms.txt) - [OpenAPI document](https://skmtc.dev/fireblocks/apis/fireblocks-api/revisions/4eba9965659a?raw)