Signal Devices API

openapi: 3.1.0
info:
  title: Signal Server Accounts Devices API
  description: The Signal Server API is the backend REST API that supports the Signal Private Messenger applications on Android, Desktop, and iOS. Built as a Dropwizard application, it provides REST controllers for account registration and management, message delivery, pre-key bundle distribution, device provisioning, profile management, and attachment handling. The server handles user registration via phone number verification, encrypted message routing, push notification delivery, and pre-key bundle management. While Signal does not offer an official public REST API for third-party use, the server source code is available for inspection and self-hosting. All communication is end-to-end encrypted using the Signal Protocol.
  version: '2.0'
  contact:
    name: Signal Support
    url: https://support.signal.org/
  termsOfService: https://signal.org/legal/
  license:
    name: AGPL-3.0
    url: https://github.com/signalapp/Signal-Server/blob/main/LICENSE
servers:
- url: https://chat.signal.org
  description: Signal Production Server
security:
- basicAuth: []
tags:
- name: Devices
  description: Device management endpoints for linking, unlinking, and managing devices associated with a Signal account.
paths:
  /v1/devices:
    get:
      operationId: listDevices
      summary: List linked devices
      description: Returns a list of all devices currently linked to the authenticated account, including device IDs, names, and last seen timestamps.
      tags:
      - Devices
      responses:
        '200':
          description: Device list returned successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DeviceList'
        '401':
          description: Authentication required
  /v1/devices/link:
    put:
      operationId: linkDevice
      summary: Link a new device
      description: Links a new device to the authenticated account. The new device must have already been provisioned with a device code obtained through the provisioning process.
      tags:
      - Devices
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/LinkDeviceRequest'
      responses:
        '200':
          description: Device linked successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DeviceResponse'
        '403':
          description: Maximum number of linked devices reached
        '422':
          description: Invalid device verification code
  /v1/devices/{deviceId}:
    delete:
      operationId: removeDevice
      summary: Remove a linked device
      description: Removes a linked device from the authenticated account. This unlinks the device and invalidates its credentials.
      tags:
      - Devices
      parameters:
      - $ref: '#/components/parameters/deviceId'
      responses:
        '204':
          description: Device removed successfully
        '401':
          description: Authentication required
        '404':
          description: Device not found
components:
  schemas:
    DeviceResponse:
      type: object
      properties:
        deviceId:
          type: integer
          format: int64
          description: The numeric device identifier assigned to the newly linked device.
    AccountAttributes:
      type: object
      properties:
        fetchesMessages:
          type: boolean
          description: Whether the device fetches messages via WebSocket rather than receiving push notifications.
        registrationId:
          type: integer
          description: The Signal Protocol registration ID for this device.
        pniRegistrationId:
          type: integer
          description: The PNI registration ID for this device.
        name:
          type: string
          description: The encrypted device name, Base64-encoded.
        capabilities:
          type: object
          description: Account capability flags indicating supported features.
          properties:
            storage:
              type: boolean
              description: Whether the account supports secure value recovery and storage service.
            transfer:
              type: boolean
              description: Whether the device supports account transfer.
            paymentActivation:
              type: boolean
              description: Whether the account supports payment activation.
        unidentifiedAccessKey:
          type: string
          description: The Base64-encoded unidentified access key for sealed sender.
        unrestrictedUnidentifiedAccess:
          type: boolean
          description: Whether any sender can use sealed sender without the access key.
    LinkDeviceRequest:
      type: object
      required:
      - verificationCode
      - accountAttributes
      properties:
        verificationCode:
          type: string
          description: The device verification code obtained during provisioning.
        accountAttributes:
          $ref: '#/components/schemas/AccountAttributes'
        aciSignedPreKey:
          $ref: '#/components/schemas/SignedPreKey'
        pniSignedPreKey:
          $ref: '#/components/schemas/SignedPreKey'
        aciPqLastResortPreKey:
          $ref: '#/components/schemas/KyberPreKey'
        pniPqLastResortPreKey:
          $ref: '#/components/schemas/KyberPreKey'
    Device:
      type: object
      properties:
        id:
          type: integer
          format: int64
          description: The numeric device identifier. Primary device is always 1.
        name:
          type: string
          description: The encrypted device name, Base64-encoded.
        lastSeen:
          type: integer
          format: int64
          description: Unix timestamp in milliseconds of when the device last connected.
        created:
          type: integer
          format: int64
          description: Unix timestamp in milliseconds of when the device was linked.
    DeviceList:
      type: object
      properties:
        devices:
          type: array
          description: List of devices linked to the account.
          items:
            $ref: '#/components/schemas/Device'
    KyberPreKey:
      type: object
      required:
      - keyId
      - publicKey
      - signature
      properties:
        keyId:
          type: integer
          format: int64
          description: The Kyber pre-key identifier.
        publicKey:
          type: string
          description: The Base64-encoded Kyber public key.
        signature:
          type: string
          description: The Base64-encoded signature over the Kyber public key.
    SignedPreKey:
      type: object
      required:
      - keyId
      - publicKey
      - signature
      properties:
        keyId:
          type: integer
          format: int64
          description: The signed pre-key identifier.
        publicKey:
          type: string
          description: The Base64-encoded public key.
        signature:
          type: string
          description: The Base64-encoded signature over the public key.
  parameters:
    deviceId:
      name: deviceId
      in: path
      required: true
      description: The numeric device identifier. Device 1 is always the primary device.
      schema:
        type: integer
        format: int64
  securitySchemes:
    basicAuth:
      type: http
      scheme: basic
      description: HTTP Basic authentication using the account UUID (or phone number) and password. The password is established during account registration.
    bearerAuth:
      type: http
      scheme: bearer
      description: Bearer token authentication used for certain provisioning and registration flows.
externalDocs:
  description: Signal Server Source Code
  url: https://github.com/signalapp/Signal-Server