Introducing fal-serverless Web Endpoints

Effortlessly serve your Python functions through a managed web server.

Introducing fal-serverless Web Endpoints

Effortlessly serve your Python functions through a managed web server.

We are excited to introduce Web Endpoints. This feature allows you to serve your Python functions through a managed web server with just a few simple steps.

What are Web Endpoints?

fal-serverless Web Endpoints are an easy way to expose your isolated Python functions through a web server managed by fal-serverless. By marking a function with the @isolated decorator and using the fal-serverless CLI command, you can effortlessly deploy your function and make it accessible via a REST API.

How to Serve a Function

To serve a function, follow these steps:

Mark the function with the @isolated decorator: Use the serve=True option to indicate that the function should be served through a web server.

def uppercase(text):
    return text.upper()

Use the fal-serverless CLI command: Run the command with the appropriate syntax, specifying the function's name and an optional alias.

fal-serverless function serve ./path/to/file uppercase --alias uppercase

>> Registered a new revision for function 'uppercase'  (revision='21847a72-93e6-4227-ae6f-56bf3a90142d').
>> URL:

After running the command, you will receive a unique revision ID and a URL to access the served function. The URL will either include the specified alias or the revision ID.

Accessing Served Functions via REST API

To call a served function, make a POST REST API request to the generated URL, replacing <userid> and <alias> with the appropriate values. Include your fal key id and key secret as headers in the request. Here's an example of a cURL request:

curl -X POST "https://<userid>-<alias>" -H "Content-Type: application/json" -H "X-Fal-Key-Id:xxxx" -H "X-Fal-Key-Secret:xxxx" -d '{"str":"str to be returned"}'

Expose Function Using Python Web Framework

If you prefer using a Python web framework like Flask or FastAPI for more control over your function, you can do so by providing an exposed_port in the @isolated decorator. For example, here's a Flask app exposed on port 8080:

@isolated(requirements=["flask"], exposed_port=8080)
def flask_app(str):
    from flask import Flask, jsonify, request

    app = Flask(__name__)

    def call_str(str):
        return jsonify({"result": str})"", port=8080)

With web endpoints, deploying your Python functions has never been easier. Create your web endpoints today and experience the simplicity and power of fal-serverless!

How are we leveraging fal Web Endpoints internally?

We are already making use of fal Web Endpoints at Features and Labels. We have a Discord bot and a GitHub webhook that runs on fal-serverless. Besides that we started to collect events about our service using Web Endpoints. We are going to get into more details about it in another post but here is a sneak peak to end the post with a simplified example:

@isolated(requirements=["duckdb"], serve=True)
def save_event(event):
    import duckdb
    import json

    con = duckdb.connect("/data/duck.db")
    con.sql("CREATE TABLE IF NOT EXISTS events (j JSON);")
    query = f"INSERT INTO events VALUES('{json.dumps(event)}')"

Serve the function using the fal-serverless command:

fal-serverless function serve ./path/to/file call_str --alias save-event

>> Registered a new revision for function 'call'  (revision='xxxx').
>> URL: https://<userid>-<alias>

Now the function is accessible through a webserver and ready to receive events from a user onboarding pipeline or directly from an application.

curl -X POST "https://<userid>-<alias>" -H "Content-Type: application/json" -H "X-Fal-Key-Id:xxxx" -H "X-Fal-Key-Secret:xxxx" -d '{"event": "user_login", "user_id": 123}'