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

# Check API health

> Returns a plain-text response when the API process is healthy.



## OpenAPI

````yaml /arc3v1.yaml get /api/healthcheck
openapi: 3.0.3
info:
  title: ARC‑AGI‑3 REST API
  version: 1.0.0
  description: >
    Programmatic interface for running agents against ARC‑AGI‑3 games,
    opening/closing score‑cards and driving game state with actions.

    All requests **require** an `X‑API‑Key` header issued from the ARC‑AGI‑3 web
    console.


    **Important: Session Affinity via Cookies**  

    Games are stateful and require session affinity. The server sets cookies
    (especially `AWSALB*` cookies) in responses that **must be included in all
    subsequent requests** for the same game session. These cookies route
    requests to the correct backend instance maintaining your game state. Most
    HTTP clients handle cookies automatically, but ensure your client preserves
    and sends cookies received from RESET and ACTION responses.
servers:
  - url: https://three.arcprize.org
security: []
tags:
  - name: Games
  - name: Scorecards
  - name: Commands
paths:
  /api/healthcheck:
    get:
      summary: Check API health
      description: Returns a plain-text response when the API process is healthy.
      operationId: healthcheck
      responses:
        '200':
          description: API process is healthy.
          content:
            text/plain:
              schema:
                type: string
              example: okay

````