Python

zbpack builds Python apps that have a requirements.txt, pyproject.toml (Poetry, uv, PDM) or Pipfile. It detects FastAPI, Django and Flask and picks a production server for each.

Framework	Start command zbpack uses
FastAPI	uvicorn main:app --host 0.0.0.0 --port 8080
Django	gunicorn --bind :8080 <project>.wsgi
Flask	gunicorn --bind :8080 main:app

The Python version defaults to 3.13; set another in .python-version, pyproject.toml or with ZBPACK_PYTHON_VERSION. To start the app differently, set ZBPACK_START_COMMAND under Settings → Build → zbpack options.

FastAPI

# main.py
from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def root():
    return {"message": "Hello from FastAPI"}

# requirements.txt
fastapi
uvicorn[standard]

zbpack takes the first of main.py, app.py, server.py and app/__init__.py that exists, and the variable assigned FastAPI(...) in it (app above). With another layout, such as app/main.py, set the start command:

ZBPACK_START_COMMAND=uvicorn app.main:app --host 0.0.0.0 --port 8080

Django

The project needs manage.py and gunicorn in requirements.txt:

django
gunicorn

Read production settings from variables in settings.py:

import os

SECRET_KEY = os.environ.get("DJANGO_SECRET_KEY", "")
DEBUG = os.environ.get("DJANGO_DEBUG") == "1"
ALLOWED_HOSTS = os.environ.get("DJANGO_ALLOWED_HOSTS", "").split(",")
CSRF_TRUSTED_ORIGINS = os.environ.get("DJANGO_CSRF_TRUSTED_ORIGINS", "").split(",")

and set them on the Variable tab:

DJANGO_SECRET_KEY=${PASSWORD}
DJANGO_ALLOWED_HOSTS=${ZENAVO_WEB_DOMAIN}
DJANGO_CSRF_TRUSTED_ORIGINS=${ZENAVO_WEB_URL}

(WEB is the name of the service's port; use the name shown on its Networking tab.)

Static files

When settings.py sets both STATIC_URL and STATIC_ROOT, zbpack runs python manage.py collectstatic --noinput during the build and serves the files with nginx in front of gunicorn, or leaves them to WhiteNoise when its middleware is in settings.py:

STATIC_URL = "static/"
STATIC_ROOT = BASE_DIR / "staticfiles"

The build has none of the service's variables, so settings.py must load without them: read DJANGO_SECRET_KEY with os.environ.get(...) as above, not os.environ[...].

Migrations

Migrations need the database, which the build cannot reach, so run them at start:

ZBPACK_START_COMMAND=python manage.py migrate --noinput && gunicorn --bind :8080 mysite.wsgi

Connect a database

Add PostgreSQL to the project and use its connection string, for example with dj-database-url or SQLAlchemy:

DATABASE_URL=${POSTGRESQL_CONNECTION_STRING}

import dj_database_url

DATABASES = {"default": dj_database_url.config(conn_max_age=600)}

Install a driver too: psycopg[binary] for PostgreSQL, mysqlclient or PyMySQL for MySQL and MariaDB.

Common problems

Symptom	Cause
ModuleNotFoundError at start	The package is missing from requirements.txt (or pyproject.toml).
Django answers 400 Bad Request	The domain is not in ALLOWED_HOSTS.
Django forms fail with CSRF verification failed	The https:// address is not in CSRF_TRUSTED_ORIGINS.
FastAPI deploy never becomes healthy	The app object is not at main:app. Set ZBPACK_START_COMMAND.
Workers are killed under load	The service's memory is too small for the number of gunicorn workers. Lower --workers, or give the service more memory.