> ## Documentation Index > Fetch the complete documentation index at: https://docs.archil.com/llms.txt > Use this file to discover all available pages before exploring further. # Fork Sandbox > Checkpoints a running source sandbox and creates an isolated writable disk branch. Forks from running or paused sources resume from the source's CPU, memory, and disk state. Forks from stopped sources cold-boot from the saved disk checkpoint. A running source is resumed after its checkpoint; paused and stopped sources remain inactive. Forked sandboxes may themselves be forked. ## OpenAPI ````yaml POST /api/sandboxes/{sid}/fork openapi: 3.1.0 info: title: Archil Control Plane API description: > The Archil Control Plane API provides programmatic access to manage disks, persistent sandboxes, mounts, and API keys in the Archil distributed filesystem platform. API keys authenticate requests to this control plane and are scoped to your account. They are distinct from *disk tokens*, which are per-disk credentials used by clients when mounting a disk. ## Authentication All endpoints require an API key: ``` Authorization: {API_KEY} ``` Create API keys in the [Archil Console](https://console.archil.com) or via the API. ## Response Format All responses use a consistent envelope: ```json { "success": true, "data": { ... } } ``` Or on error: ```json { "success": false, "error": "Error message" } ``` version: 1.0.0 contact: email: support@archil.com url: https://archil.com servers: - url: https://control.green.us-east-1.aws.prod.archil.com description: AWS US East (N. Virginia) — aws-us-east-1 - url: https://control.green.eu-west-1.aws.prod.archil.com description: AWS EU West (Ireland) — aws-eu-west-1 - url: https://control.green.us-west-2.aws.prod.archil.com description: AWS US West (Oregon) — aws-us-west-2 - url: https://control.blue.us-central1.gcp.prod.archil.com description: GCP US Central (Iowa) — gcp-us-central1 security: - ApiKeyAuth: [] tags: - name: Disks description: Create, read, update, and delete disks - name: Serverless Execution description: Run commands on a disk without provisioning compute - name: Sandboxes description: Manage persistent sandbox virtual machines - name: Disk Users description: Manage authorized users on disks - name: API Tokens description: >- Manage API keys (also called API tokens) used to authenticate Control Plane API requests. Distinct from disk tokens. paths: /api/sandboxes/{sid}/fork: post: tags: - Sandboxes summary: Fork a sandbox description: | Checkpoints a running source sandbox and creates an isolated writable disk branch. Forks from running or paused sources resume from the source's CPU, memory, and disk state. Forks from stopped sources cold-boot from the saved disk checkpoint. A running source is resumed after its checkpoint; paused and stopped sources remain inactive. Forked sandboxes may themselves be forked. operationId: forkSandbox parameters: - $ref: '#/components/parameters/SandboxId' - $ref: '#/components/parameters/Wait' requestBody: required: false content: application/json: schema: $ref: '#/components/schemas/ForkSandboxRequest' responses: '202': description: The fork was created and its start is pending content: application/json: schema: $ref: '#/components/schemas/ApiResponse_Sandbox' '400': $ref: '#/components/responses/ValidationError' '401': $ref: '#/components/responses/Unauthorized' '404': $ref: '#/components/responses/NotFound' '409': description: The source cannot be paused or its fork checkpoint is unavailable content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '500': $ref: '#/components/responses/InternalError' '503': $ref: '#/components/responses/RetryableUnavailable' components: parameters: SandboxId: name: sid in: path required: true description: Sandbox UUID schema: type: string format: uuid Wait: name: wait in: query required: false description: Hold the request for a completed start or exec result schema: type: boolean default: false schemas: ForkSandboxRequest: type: object properties: name: type: string minLength: 1 maxLength: 63 pattern: ^[a-z0-9]([-a-z0-9]*[a-z0-9])?$ description: >- Name for the fork. A random word-list name is generated when omitted. ApiResponse_Sandbox: type: object required: - success - data properties: success: type: boolean example: true data: $ref: '#/components/schemas/Sandbox' ErrorResponse: type: object required: - success - error properties: success: type: boolean example: false error: type: string example: Invalid request parameters Sandbox: type: object required: - sandbox_id - name - status - vcpu_count - mem_size_mib - max_ttl_seconds - max_concurrent_execs - base_image - created_at - last_active_at properties: sandbox_id: type: string format: uuid name: type: string minLength: 1 maxLength: 63 pattern: ^[a-z0-9]([-a-z0-9]*[a-z0-9])?$ description: Sandbox name. status: $ref: '#/components/schemas/SandboxState' vcpu_count: type: integer mem_size_mib: type: integer max_ttl_seconds: type: integer description: >- Lifetime budget for each powered-on session. Activity does not extend the deadline; starting or resuming the sandbox begins a fresh session. max_concurrent_execs: type: integer base_image: type: string description: OCI reference requested when the sandbox was created. platform: type: string enum: - arm64 - amd64 description: Sandbox CPU architecture. endpoints: type: array items: $ref: '#/components/schemas/SandboxEndpoint' created_at: type: string format: date-time running_at: type: string format: date-time finished_at: type: string format: date-time last_active_at: type: string format: date-time expires_at: type: string format: date-time description: Current powered-on session deadline; absent while inactive. exit_reason: type: string SandboxState: type: string enum: - pending - running - pausing - paused - stopping - stopped - exited - failed - deleting - deleted SandboxEndpoint: type: object required: - port - hostname properties: port: type: integer minimum: 1 maximum: 65535 hostname: type: string responses: ValidationError: description: Validation error content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' Unauthorized: description: Invalid or missing authentication credentials content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' NotFound: description: Resource not found content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' InternalError: description: Internal server error content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' RetryableUnavailable: description: The lifecycle transition is temporarily blocked and can be retried content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' securitySchemes: ApiKeyAuth: type: apiKey in: header name: Authorization description: API key ````