Static Egress IPs for Heroku API Calls with Proximo

Use an existing Proximo integration for outbound IP allowlisting while keeping application ingress on Heroku’s web route.

A partner API can require requests from a known source IP while the Heroku app calling it runs on changing dynos. An existing Proximo integration provides an outbound path through an assigned static address.

dyno’s API client → Proximo gateway → partner API
                         assigned source IP

The assigned egress address is what belongs in the partner’s source allowlist. PROXIMO_URL identifies the proxy endpoint and credentials the application uses to enter that path; it is not the app’s public website URL.

Apply the route to the process making the call

A web process and a background worker can make separate API requests. Configure each required consumer through its supported proxy integration. Routing one process does not establish that every other process uses the gateway.

For a JVM application, use an appropriate native HTTP or SOCKS client configuration and the provider’s supported authentication arrangement. Do not infer Java compatibility from a wrapper example written for another runtime.

Keep incoming requests on the application’s route

Proximo’s Heroku documentation explicitly says it does not provide inbound application access. Clients reaching the web app still use its configured Heroku hostname and routing arrangement.

Use the app URL to check incoming web access. Use evidence from the partner’s received requests to check the outbound source address. Expecting the static proxy IP to serve the app combines those two directions into a feature the outbound service does not provide.

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