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Static IP guide

Making API requests with a static IP from a Python app on Fly.io

Python apps on Fly.io route requests through Fixie by reading FIXIE_URL from a Fly secret into a proxies dict — or by exporting http_proxy and https_proxy for zero code changes. Machines may move between hosts and regions; the outbound addresses your partners see will not.

RuntimePython
PlatformFly.io
DestinationAPI allowlisting
Fixie productFixie HTTP/S proxy

Recommended setup

Use Fixie HTTP/S proxy for HTTP and HTTPS requests to an API, webhook provider, or service that allowlists outbound IP addresses. Store the proxy value in FIXIE_URL, then configure Python to route outbound traffic through Fixie before connecting to API allowlisting.

Set up Fixie on Fly.io

Create a Fixie HTTP/S proxy in the Fixie dashboard. Copy the proxy value into Fly.io secrets as FIXIE_URL, and copy the outbound IPs into the destination allowlist.

Set a Fly.io secret

fly secrets set FIXIE_URL=...

Implementation

The example below shows the core application-side change. Keep credentials in environment variables and avoid committing proxy, database, or API secrets.

Make an HTTP request through FIXIE_URL

import os
import requests

proxies = {
    "http": os.environ["FIXIE_URL"],
    "https": os.environ["FIXIE_URL"],
}

response = requests.get("https://api.example.com/data", proxies=proxies)
print(response.status_code)

Good to know

  • Store the value with fly secrets set FIXIE_URL=... rather than in fly.toml, which is committed to your repo.
  • If several Fly apps in one organization call the same allowlisted API, they can share a single Fixie proxy and its IP pair.

Allowlist and test the static IPs

  1. Open the Fixie dashboard and copy the outbound IP addresses for this proxy.
  2. Add both IPs to the API provider.
  3. Deploy the updated Python app on Fly.io.
  4. Run a small connection test before sending production traffic.

Related guides

Related docs