This changelog documents user-facing updates (features, enhancements, fixes, and deprecations) to the modal client library. Patch releases are made on every change.

The client library is still in pre-1.0 development, and sometimes breaking changes are necessary. We try to minimize them and publish deprecation warnings / migration guides in advance, typically providing a transition window of several months.

We appreciate your patience while we speedily work towards a stable release of the client.


0.62.55 (2024-04-11)

  • When Volume reloads fail due to an open file, we now try to identify and report the relevant path. Note that there may be some circumstances in which we are unable to identify the specific file blocking a reload and will report a generic error message in that case.

0.62.53 (2024-04-10)

  • Values in the modal.toml config file that are spelled as 0, false, "False", or "false" will now be coerced in Python toFalse, whereas previously only "0" (as a string) would have the intended effect.

0.62.25 (2024-04-01)

  • Fixed a recent regression that caused functions using modal.interact() to crash.

0.62.15 (2024-03-29)

  • Queue methods put, put_many, get, get_many and len now support an optional partition argument (must be specified as a kwarg). When specified, users read and write from new partitions of the queue independently. partition=None corresponds to the default partition of the queue.

0.62.3 (2024-03-27)

  • User can now mount S3 buckets using Requester Pays. This can be done with CloudBucketMount(..., requester_pays=True).

0.62.1 (2024-03-27)

  • Raise an error on @web_server(startup_timeout=0), which is an invalid configuration.

0.62.0 (2024-03-26)

  • The .new() method has now been deprecated on all Modal objects. It should typically be replaced with .from_name(...) in Modal app code, or .ephemeral() in scripts that use Modal
  • Assignment of Modal objects to a Stub via subscription (stub["object"]) or attribute (stub.object) syntax is now deprecated. This syntax was only necessary when using .new().


0.61.104 (2024-03-25)

  • Fixed a bug where images based on micromamba could fail to build if requesting Python 3.12 when a different version of Python was being used locally.

0.61.76 (2024-03-19)

  • The Sandbox’s LogsReader is now an asynchronous iterable. It supports the async for statement to stream data from the sandbox’s stdout/stderr.
async def my_fn():
    sandbox = stub.spawn_sandbox(
      "while true; do echo foo; sleep 1; done"
    async for message in sandbox.stdout:
        print(f"Message: {message}")

0.61.57 (2024-03-15)

  • Add the @web_server decorator, which exposes a server listening on a container port as a web endpoint.

0.61.56 (2024-03-15)

  • Allow users to write to the Sandbox’s stdin with StreamWriter.
def my_fn():
    sandbox = stub.spawn_sandbox(
        "while read line; do echo $line; done",

0.61.53 (2024-03-15)

  • Fixed an bug whereMount was failing to include symbolic links.

0.61.45 (2024-03-13)

When called from within a container, modal.experimental.stop_fetching_inputs() causes it to gracefully exit after the current input has been processed.

0.61.35 (2024-03-12)

  • The @wsgi_app() decorator now uses a different backend based on a2wsgi that streams requests in chunks, rather than buffering the entire request body.

0.61.32 (2024-03-11)

  • Stubs/apps can now be “composed” from several smaller stubs using stub.include(...). This allows more ergonomic setup of multi-file Modal apps.

0.61.31 (2024-03-08)

  • The Image.extend method has been deprecated. This is a low-level interface and can be replaced by other Image methods that offer more flexibility, such as Image.from_dockerfile, Image.dockerfile_commands, or Image.run_commands.

0.61.24 (2024-03-06)

  • Fixes modal volume put to support uploading larger files, beyond 40 GiB.

0.61.22 (2024-03-05)

  • Modal containers now display a warning message if lingering threads are present at container exit, which prevents runner shutdown.

0.61.17 (2024-03-05)

  • Bug fix: Stopping an app while a container’s @exit() lifecycle methods are being run no longer interrupts the lifecycle methods.
  • Bug fix: Worker preemptions no longer interrupt a container’s @exit() lifecycle method (until 30 seconds later).
  • Bug fix: Async @exit() lifecycle methods are no longer skipped for sync functions.
  • Bug fix: Stopping a sync function with allow_concurrent_inputs>1 now actually stops the container. Previously, it would not propagate the signal to worker threads, so they would continue running.
  • Bug fix: Input-level cancellation no longer skips the @exit() lifecycle method.
  • Improve stability of container entrypoint against race conditions in task cancellation.

0.61.9 (2024-03-05)

  • Fix issue with pdm where all installed packages would be automounted when using package cache (MOD-2485)

0.61.6 (2024-03-04)

  • For modal functions/classes with concurrency_limit < keep_warm, we’ll raise an exception now. Previously we (silently) respected the concurrency_limit parameter.

0.61.1 (2024-03-03)

modal run --interactive or modal run -i run the app in “interactive mode”. This allows any remote code to connect to the user’s local terminal by calling modal.interact().

def my_fn(x):

    x = input()
    print(f"Your number is {x}")

This means that you can dynamically start an IPython shell if desired for debugging:

def my_fn(x):

    from IPython import embed

For convenience, breakpoints automatically call interact():

def my_fn(x):


0.60.0 (2024-02-29)

  • Image.run_function now allows you to pass args and kwargs to the function. Usage:
def my_build_function(name, size, *, variant=None):
    print(f"Building {name} {size} {variant}")

image = modal.Image.debian_slim().run_function(
    my_build_function, args=("foo", 10), kwargs={"variant": "bar"}


0.59.0 (2024-02-28)

  • Mounted packages are now deduplicated across functions in the same stub
  • Mounting of local Python packages are now marked as such in the mount creation output, e.g. PythonPackage:my_package
  • Automatic mounting now includes packages outside of the function file’s own directory. Mounted packages are mounted in /root/


0.58.92 (2024-02-27)

  • Most errors raised through usage of the CLI will now print a simple error message rather than showing a traceback from inside the modal library.
  • Tracebacks originating from user code will include fewer frames from within modal itself.
  • The new MODAL_TRACEBACK environment variable (and traceback field in the Modal config file) can override these behaviors so that full tracebacks are always shown.

0.58.90 (2024-02-27)

  • Fixed a bug that could cause cls-based functions to to ignore timeout signals.

0.58.88 (2024-02-26)

  • volume get performance is improved for large (> 100MB) files

0.58.79 (2024-02-23)

  • Support for function parameters in methods decorated with @exit has been deprecated. Previously, exit methods were required to accept three arguments containing exception information (akin to __exit__ in the context manager protocol). However, due to a bug, these arguments were always null. Going forward, @exit methods are expected to have no parameters.

0.58.75 (2024-02-23)

  • Function calls can now be cancelled without killing the container running the inputs. This allows new inputs by different function calls to the same function to be picked up immediately without having to cold-start new containers after cancelling calls.


0.57.62 (2024-02-21)

  • An InvalidError is now raised when a lifecycle decorator (@build, @enter, or @exit) is used in conjunction with @method. Previously, this was undefined and could produce confusing failures.

0.57.61 (2024-02-21)

  • Reduced the amount of context for frames in modal’s CLI framework when showing a traceback.

0.57.60 (2024-02-21)

  • The “dunder method” approach for class lifecycle management (__build__, __enter__, __exit__, etc.) is now deprecated in favor of the modal @build, @enter, and @exit decorators.

0.57.52 (2024-02-17)

  • In modal token new and modal token set, the --no-no-verify flag has been removed in favor of a --verify flag. This remains the default behavior.

0.57.51 (2024-02-17)

  • Fixes a regression from 0.57.40 where @enter methods used a separate event loop.

0.57.42 (2024-02-14)

  • Adds a new environment variable/config setting, MODAL_FORCE_BUILD/force_build, that coerces all images to be built from scratch, rather than loaded from cache.

0.57.40 (2024-02-13)

  • The @enter() lifecycle method can now be used to run additional setup code prior to function checkpointing (when the class is decorated with stub.cls(enable_checkpointing=True). Note that there are currently some limitations on function checkpointing:
    • Checkpointing only works for CPU memory; any GPUs attached to the function will not available
    • Networking is disabled while the checkpoint is being created
  • Please note that function checkpointing is still a beta feature.

0.57.31 (2024-02-12)

  • Fixed an issue with displaying deprecation warnings on Windows systems.

0.57.22 (2024-02-09)

  • Modal client deprecation warnings are now highlighted in the CLI

0.57.16 (2024-02-07)

  • Fixes a regression in container scheduling. Users on affected versions ( are encouraged to upgrade immediately.

0.57.15 (2024-02-07)

  • The legacy image_python_version config option has been removed. Use the python_version= parameter on your image definition instead.

0.57.13 (2024-02-07)

  • Adds support for mounting an S3 bucket as a volume.

0.57.9 (2024-02-07)

  • Support for an implicit ‘default’ profile is now deprecated. If you have more than one profile in your Modal config file, one must be explicitly set to active (use modal profile activate or edit your .modal.toml file to resolve).
  • An error is now raised when more than one profile is set to active.

0.57.2 (2024-02-06)

  • Improve error message when generator functions are called with .map(...).

0.57.0 (2024-02-06)

  • Greatly improved streaming performance of generators and WebSocket web endpoints.
  • Breaking change: You cannot use .map() to call a generator function. (In previous versions, this merged the results onto a single stream, but the behavior was undocumented and not widely used.)
  • Incompatibility: Generator outputs are now on a different internal system. Modal code on client versions before 0.57 cannot trigger deployed functions with .remote_gen() that are on client version 0.57, and vice versa.


Note that in version 0.56 and prior, Modal used a different numbering system for patch releases.

0.56.4964 (2024-02-05)

  • When using modal token new or model token set, the profile containing the new token will now be activated by default. Use the --no-activate switch to update the modal.toml file without activating the corresponding profile.

0.56.4953 (2024-02-05)

  • The modal profile list output now indicates when the workspace is determined by a token stored in environment variables.

0.56.4952 (2024-02-05)

  • Variadic parameters (e.g. *args and **kwargs) can now be used in scheduled functions as long as the function doesn’t have any other parameters without a default value

0.56.4903 (2024-02-01)

  • modal container exec’s --no-tty flag has been renamed to --no-pty.

0.56.4902 (2024-02-01)

  • The singular form of the secret parameter in Stub.function, Stub.cls, and Image.run_function has been deprecated. Please update your code to use the plural form instead:secrets=[Secret(...)].

0.56.4885 (2024-02-01)

  • In modal profile list, the user’s GitHub username is now shown as the name for the “Personal” workspace.

0.56.4874 (2024-01-31)

  • The modal token new and modal token set commands now create profiles that are more closely associated with workspaces, and they have more explicit profile activation behavior:
    • By default, these commands will create/update a profile named after the workspace that the token points to, rather than a profile named “default”
    • Both commands now have an --activate flag that will activate the profile associated with the new token
    • If no other profiles exist at the time of creation, the new profile will have its active metadata set to True
  • With these changes, we are moving away from the concept of a “default” profile. Implicit usage of the “default” profile will be deprecated in a future update.

0.56.4849 (2024-01-29)

  • Adds tty support to modal container exec for fully-interactive commands. Example: modal container exec [container-id] /bin/bash

0.56.4792 (2024-01-26)

  • The modal profile list command now shows the workspace associated with each profile.

0.56.4715 (2024-01-24)

  • Mount.from_local_python_packages now places mounted packages at /root in the Modal runtime by default (used to be /pkg). To override this behavior, the function now takes a remote_dir: Union[str, PurePosixPath] argument.

0.56.4707 (2024-01-23)

  • The Modal client library is now compatible with Python 3.12, although there are a few limitations:

    • Images that use Python 3.12 without explicitly specifing it through python_version or add_python will not build properly unless the modal client is also running on Python 3.12.
    • The conda and microconda base images currently do not support Python 3.12 because an upstream dependency is not yet compatible.

0.56.4700 (2024-01-22)

  • gpu.A100 class now supports specifying GiB memory configuration using a size: str parameter. The memory: int parameter is deprecated.

0.56.4693 (2024-01-22)

  • You can now execute commands in running containers with modal container exec [container-id] [command].

0.56.4691 (2024-01-22)

  • The modal cli now works more like the python cli in regard to script/module loading:
    • Running modal my_dir/ now puts my_dir on the PYTHONPATH.
    • modal my_package.my_module will now mount to /root/my_package/ in your Modal container, regardless if using automounting or not (and any intermediary files will also be mounted)

0.56.4687 (2024-01-20)

  • Modal now uses the current profile if MODAL_PROFILE is set to the empty string.

0.56.4649 (2024-01-17)

  • Dropped support for building Python 3.7 based modal.Images. Python 3.7 is end-of-life since late June 2023.

0.56.4620 (2024-01-16)

  • modal.Stub.function now takes a block_network argument.

0.56.4616 (2024-01-16)

  • modal.Stub now takes a volumes argument for setting the default volumes of all the stub’s functions, similarly to the mounts and secrets argument.

0.56.4590 (2024-01-13)

  • modal serve: Setting MODAL_LOGLEVEL=DEBUG now displays which files cause an app reload during serve

0.56.4570 (2024-01-12)

  • modal run cli command now properly propagates --env values to object lookups in global scope of user code