Modal
Modal Functions API

Modal Functions are the core serverless primitive — Python functions backed by autoscaling container pools. They support optional GPU attachment (T4 through B200), Modal-built container images, Volumes, Secrets, retries, timeouts, scheduling, web endpoints, dynamic batching, and class-based stateful workers. Invoke synchronously (`.remote()`), asynchronously (`.spawn()`), or as a map (`.map()`).
Documentation GitHub OpenAPI
OpenAPI Specification

openapi: 3.1.0
info:
  title: Modal Functions API
  description: |
    Conceptual REST surface for Modal Functions — Modal's core primitive
    for serverless container-backed Python functions with autoscaling
    container pools, GPU attachment, web endpoints, and remote invocation.

    This specification mirrors the operations exposed by the Modal Python
    SDK (`modal.App`, `modal.Function`) and the `modal` CLI. The Modal
    control plane is gRPC over HTTP/2; this OpenAPI document describes
    the equivalent resource-oriented surface to aid governance, capability
    composition, and toolchain integration.
  version: 0.1.0
  contact:
    name: Modal Labs
    url: https://modal.com
  license:
    name: Modal Terms of Service
    url: https://modal.com/legal/terms
servers:
- url: https://api.modal.com/v1
  description: Modal control plane
tags:
- name: Apps
  description: Modal App lifecycle.
- name: Functions
  description: Modal Function definitions, invocations, and scaling.
- name: Invocations
  description: Asynchronous function invocations and result retrieval.
paths:
  /apps:
    get:
      tags:
      - Apps
      summary: List Apps
      description: List all Modal apps in the current workspace and environment.
      operationId: listApps
      parameters:
      - name: environment
        in: query
        schema:
          type: string
      - name: state
        in: query
        schema:
          type: string
          enum: [ephemeral, deployed, stopped]
      responses:
        '200':
          description: A page of apps.
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items:
                      $ref: '#/components/schemas/App'
    post:
      tags:
      - Apps
      summary: Create App
      description: Create a new ephemeral or deployed Modal app.
      operationId: createApp
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/AppCreate'
      responses:
        '201':
          description: App created.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/App'
  /apps/{app_id}:
    get:
      tags:
      - Apps
      summary: Get App
      description: Retrieve a single Modal app by ID.
      operationId: getApp
      parameters:
      - name: app_id
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: The app.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/App'
    delete:
      tags:
      - Apps
      summary: Stop App
      description: Stop a running Modal app and tear down its containers.
      operationId: stopApp
      parameters:
      - name: app_id
        in: path
        required: true
        schema:
          type: string
      responses:
        '204':
          description: App stopped.
  /apps/{app_id}/functions:
    get:
      tags:
      - Functions
      summary: List Functions
      description: List all Functions registered in the given app.
      operationId: listFunctions
      parameters:
      - name: app_id
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: A page of functions.
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items:
                      $ref: '#/components/schemas/Function'
  /functions/{function_id}:
    get:
      tags:
      - Functions
      summary: Get Function
      description: Retrieve a Modal Function by ID.
      operationId: getFunction
      parameters:
      - name: function_id
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: The Function.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Function'
  /functions/{function_id}/invocations:
    post:
      tags:
      - Invocations
      summary: Invoke Function
      description: |
        Synchronously invoke a Modal Function. The request body is the
        serialized argument payload; the response contains the
        serialized return value or an invocation error.
      operationId: invokeFunction
      parameters:
      - name: function_id
        in: path
        required: true
        schema:
          type: string
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/InvocationRequest'
      responses:
        '200':
          description: Invocation completed.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/InvocationResult'
    get:
      tags:
      - Invocations
      summary: List Invocations
      description: List recent invocations for the given Function.
      operationId: listInvocations
      parameters:
      - name: function_id
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: A page of invocations.
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items:
                      $ref: '#/components/schemas/InvocationResult'
  /functions/{function_id}/spawn:
    post:
      tags:
      - Invocations
      summary: Spawn Asynchronous Invocation
      description: |
        Spawn an asynchronous Function call and return a FunctionCall
        handle. The result is fetched later via the FunctionCall ID.
      operationId: spawnFunction
      parameters:
      - name: function_id
        in: path
        required: true
        schema:
          type: string
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/InvocationRequest'
      responses:
        '202':
          description: Invocation accepted.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/FunctionCall'
  /function-calls/{call_id}:
    get:
      tags:
      - Invocations
      summary: Get Function Call
      description: Retrieve the status and result of an async FunctionCall.
      operationId: getFunctionCall
      parameters:
      - name: call_id
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: The FunctionCall result.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/FunctionCall'
components:
  schemas:
    App:
      type: object
      properties:
        app_id:
          type: string
        name:
          type: string
        state:
          type: string
          enum: [ephemeral, deployed, stopped]
        environment:
          type: string
        tags:
          type: object
          additionalProperties:
            type: string
        created_at:
          type: string
          format: date-time
    AppCreate:
      type: object
      required: [name]
      properties:
        name:
          type: string
        environment:
          type: string
        tags:
          type: object
          additionalProperties:
            type: string
    Function:
      type: object
      properties:
        function_id:
          type: string
        app_id:
          type: string
        name:
          type: string
        image:
          type: string
        gpu:
          type: string
          description: GPU type spec (e.g. T4, L4, A10, A100-40GB, A100-80GB, L40S, H100, H200, B200, RTX-PRO-6000).
        cpu:
          type: number
        memory:
          type: integer
          description: Memory in MiB.
        timeout:
          type: integer
        retries:
          type: integer
        min_containers:
          type: integer
        max_containers:
          type: integer
        web_url:
          type: string
          format: uri
    InvocationRequest:
      type: object
      properties:
        args:
          type: array
          items: {}
        kwargs:
          type: object
          additionalProperties: true
    InvocationResult:
      type: object
      properties:
        call_id:
          type: string
        status:
          type: string
          enum: [pending, running, success, failure, terminated]
        result:
          nullable: true
        error:
          type: object
          nullable: true
        started_at:
          type: string
          format: date-time
        finished_at:
          type: string
          format: date-time
    FunctionCall:
      type: object
      properties:
        call_id:
          type: string
        function_id:
          type: string
        status:
          type: string
          enum: [pending, running, success, failure, terminated]
        result:
          nullable: true
  securitySchemes:
    ModalToken:
      type: http
      scheme: bearer
      description: Modal token id and token secret pair (`MODAL_TOKEN_ID` + `MODAL_TOKEN_SECRET`).
security:
- ModalToken: []
Modal Functions API

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OpenAPI Specification
