API Reference

This is the API reference for the modal Python package, which allows you to run distributed applications on Modal.

The reference is intended to be limited to low-level descriptions of various programmatic functionality. If you’re just getting started with Modal, we would instead recommend looking at the guide first or to get started quickly with an example.

Application construction


`App`	The main unit of deployment for code on Modal
`App.function`	Decorator for registering a function with an App
`App.cls`	Decorator for registering a class with an App

Serverless execution


`Function`	A serverless function backed by an autoscaling container pool
`Cls`	A serverless class supporting parametrization and lifecycle hooks

Extended Function configuration

Class parametrization


`parameter`	Used to define class parameters, akin to a Dataclass field

Lifecycle hooks


`enter`	Decorator for a method that will be executed during container startup
`exit`	Decorator for a method that will be executed during container shutdown
`method`	Decorator for exposing a method as an invokable function

Web integrations


`fastapi_endpoint`	Decorator for exposing a simple FastAPI-based endpoint
`asgi_app`	Decorator for functions that construct an ASGI web application
`wsgi_app`	Decorator for functions that construct a WSGI web application
`web_server`	Decorator for functions that construct an HTTP web server

Function semantics


`batched`	Decorator that enables dynamic input batching
`concurrent`	Decorator that enables input concurrency

Scheduling


`Cron`	A schedule that runs based on cron syntax
`Period`	A schedule that runs at a fixed interval

Exception handling


`Retries`	Function retry policy for input failures

Sandboxed execution


`Sandbox`	An interface for restricted code execution
`ContainerProcess`	An object representing a sandboxed process
`FileIO`	A handle for a file in the Sandbox filesystem

Container configuration


`Image`	An API for specifying container images
`Secret`	A pointer to secrets that will be exposed as environment variables

Data primitives

Persistent storage


`Volume`	Distributed storage supporting highly performant parallel reads
`CloudBucketMount`	Storage backed by a third-party cloud bucket (S3, etc.)
`NetworkFileSystem`	Shared, writeable cloud storage (superseded by `modal.Volume`)

In-memory storage


`Dict`	A distributed key-value store
`Queue`	A distributed FIFO queue

Networking


`Proxy`	An object that provides a static outbound IP address for containers
`forward`	A context manager for publicly exposing a port from a container