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Static IP guide

Making API requests with a static IP from a Ruby app on Render

Rails and Sinatra apps on Render integrate Fixie the same way they would anywhere Ruby runs: RestClient.proxy = ENV["FIXIE_URL"] in an initializer, or a per-connection proxy option in Faraday. The only Render-specific step is creating the FIXIE_URL environment variable yourself, since there is no add-on marketplace to do it for you.

RuntimeRuby
PlatformRender
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 Ruby to route outbound traffic through Fixie before connecting to API allowlisting.

Set up Fixie on Render

Create a Fixie HTTP/S proxy in the Fixie dashboard. Copy the proxy value into Render Environment Variables as FIXIE_URL, and copy the outbound IPs into the destination allowlist.

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

require "rest-client"

RestClient.proxy = ENV["FIXIE_URL"]
response = RestClient.get("https://api.example.com/data")

puts response.code

Good to know

  • Set the variable in the Render dashboard or render.yaml, then redeploy — Render restarts the service with the new environment.
  • Outbound webhooks originate from your Fixie IPs once the initializer runs, so register those two addresses with the receiving service.

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 Ruby app on Render.
  4. Run a small connection test before sending production traffic.

Related guides

Related docs