Python Builder (@now/python)

Status: Alpha

This builder takes in a Python program that defines a singular HTTP handler and outputs it as a Lambda.

When to Use It

Whenever you want to expose an API or a function written in Python.

How to Use It

Define a file inside a folder as follows:

from http.server import BaseHTTPRequestHandler
from cowpy import cow

class handler(BaseHTTPRequestHandler):

    def do_GET(self):
        message = cow.Cowacter().milk('Hello from Python on Now Lambda!1111111')

Inside requirements.txt define:


And define a now.json like:

  "version": 2,
  "builds": [{ "src": "*.py", "use": "@now/python" }]

The example above can be seen live as

Also, the source code of the deployment can be checked by appending /_src e.g.

Technical Details


The entrypoint file must be a .py source file with a handler that inherits from the BaseHTTPRequestHandler class.


This builder supports installing dependencies defined in the requirements.txt file.

Maximum Lambda Bundle Size

To help keep cold boot times low, the maximum output bundle size for a Python lambda is, by default, 5mb. This limit is extendable up to 50mb.

Example maxLambdaSize configuration:
  "builds": [
    { "src": "*.py", "use": "@now/python", "config": { "maxLambdaSize": "10mb" } }