> ## Documentation Index
> Fetch the complete documentation index at: https://docs.arb.inc/llms.txt
> Use this file to discover all available pages before exploring further.

# Add a participant to a case

> Adds a user to a case. You must be logged into an organization, and the user you add must be in the same organization.



## OpenAPI

````yaml /api-reference/api.yaml post /participants/add
openapi: 3.0.3
info:
  title: api
  description: >-
    The API service is the secure public gateway to our platform, letting people
    access features without touching our private internal APIs. It authenticates
    clients with its own internal tokens and then routes their requests to the
    right internal services behind the scenes.
  version: 1.0.0
servers:
  - url: https://api.platform.arb.inc
security: []
tags:
  - name: cases
  - name: docket
  - name: evidence
  - name: filings
  - name: organization
  - name: participants
  - name: schemas
  - name: service-of-notice
paths:
  /participants/add:
    post:
      tags:
        - participants
      summary: Add a participant to a case
      description: >-
        Adds a user to a case. You must be logged into an organization, and the
        user you add must be in the same organization.
      operationId: addCaseParticipant
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
                - caseID
                - userID
              properties:
                caseID:
                  type: string
                  description: Target case identifier (1–36 chars).
                  minLength: 1
                  maxLength: 36
                  example: 2025-10-00123
                userID:
                  type: string
                  format: uuid
                  description: UUID of the user to add.
                  example: 8f1b2c33-2db3-4a9e-9f44-5d5a6c7b8e90
                isObserver:
                  type: boolean
                  description: If true, the user is added as an observer.
                  example: false
      responses:
        '200':
          description: Participant was successfully added to the case
          content:
            text/plain:
              schema:
                type: string
                example: participant was successfully added to the case
      security:
        - bearerAuth: []
components:
  securitySchemes:
    bearerAuth:
      type: http
      description: access token
      scheme: bearer
      bearerFormat: JWT

````