Firebase Functions Python SDK

Warnings

• gotcha Python support for Cloud Functions for Firebase is in Public Preview. This means the functionality might change in backward-incompatible ways, is not subject to any SLA or deprecation policy, and may receive limited support.
  Fix: Be aware of potential changes and review release notes carefully. Consider stability requirements for production applications.
• breaking The `firebase-functions` library requires Python 3.10 or higher. The `firebase-admin` SDK (a common dependency) also dropped support for Python 3.7 and 3.8, and deprecated 3.9, with version 7.0.0. Ensure your local environment and deployment runtime are on a supported Python version (3.10-3.13).
  Fix: Update your Python environment to Python 3.10 or newer. When deploying, ensure `runtime` is explicitly set to `python310`, `python311`, `python312`, or `python313` if not using the default (which is currently 3.13).
• gotcha When using `firebase-admin` within your functions, you must explicitly `import firebase_admin` (in addition to any submodules like `firebase_admin.auth`) before calling `firebase_admin.initialize_app()`. Failure to do so will result in a `NameError`. Also, ensure `firebase-admin` is listed in your `requirements.txt`.
  Fix: Always include `import firebase_admin` at the top of your function file, even if you only use submodules. Ensure `firebase-admin` is in `requirements.txt`.
• gotcha To avoid 'cold start' performance issues, reuse expensive objects (like database connections, API clients, or large data structures) by declaring them as global variables outside of your function handler. They will be initialized once per container instance, rather than on every function invocation.
  Fix: Move resource-intensive initialization code to the global scope of your `main.py` file.
• gotcha Ensure all Python package dependencies are correctly specified in `requirements.txt` within your functions directory. Missing or incorrect dependencies can lead to deployment failures or runtime errors in your deployed functions.
  Fix: Double-check `requirements.txt` for all necessary packages, including `firebase-functions` and `firebase-admin`. Use `pip freeze > requirements.txt` in a clean virtual environment to capture exact versions.
• gotcha Deployment region needs to be explicitly specified for optimal performance and compliance. If not set, functions will deploy to the default `us-central1`. You can set a global region using `options.set_global_options(region=options.SupportedRegion.YOUR_REGION)` or per function.
  Fix: Set a global region via `options.set_global_options()` or specify `region` argument in the function decorator (e.g., `@https_fn.on_request(region='europe-west1')`).

Install

• pip install firebase-functions Install latest version

Imports

• https_fn

  from firebase_functions import https_fn

• firestore_fn

  from firebase_functions import firestore_fn

• options

  from firebase_functions import options

• initialize_app
  wrong:

  import firebase_admin; initialize_app()

  correct:

  from firebase_admin import initialize_app

  You must explicitly import `firebase_admin` before calling `initialize_app()` or you will encounter a `NameError`. Ensure `firebase_admin` is also in your `requirements.txt`.

Quickstart

This quickstart defines a simple HTTP-triggered function that responds with a greeting. It demonstrates initializing the Firebase Admin SDK (which is automatic in Cloud Functions environments) and handling basic request parameters. To deploy, save this as `main.py` in your functions directory, add `firebase-functions` and `firebase-admin` to `requirements.txt`, and run `firebase deploy --only functions`.

import os
from firebase_functions import https_fn
from firebase_admin import initialize_app

# Initialize the Firebase Admin SDK. When deployed to Cloud Functions,
# the SDK automatically detects the environment's service account credentials.
initialize_app()

@https_fn.on_request()
def hello_world(request: https_fn.Request) -> https_fn.Response:
    """Responds to an HTTP request with a 'Hello from Python!' message."""
    # Example of accessing environment variables (if any are set during deployment)
    message_prefix = os.environ.get('MESSAGE_PREFIX', 'Hello')

    # Check for a 'name' query parameter or use a default.
    name = request.args.get('name', 'World')

    return https_fn.Response(f"{message_prefix}, {name} from Python!")