Static Outbound IP
for Serverless Environments

// Node.js — Route outbound requests through CORSPROXY
const PROXY = 'https://corsproxy.io/?url=';

async function callWhitelistedAPI(endpoint: string, apiKey: string) {
  const response = await fetch(
    PROXY + encodeURIComponent(endpoint),
    {
      method: 'GET',
      headers: {
        'Authorization': `Bearer ${apiKey}`,
        'Content-Type': 'application/json',
      },
    }
  );
  return response.json();
}

// Your Cloud Run service calls the external API through CORSPROXY
// The external API sees CORSPROXY's static IP, not Cloud Run's dynamic IP
const data = await callWhitelistedAPI(
  'https://api.partner.com/v1/data',
  process.env.PARTNER_API_KEY
);

# Python — Static IP egress via CORSPROXY
import requests

PROXY = "https://corsproxy.io/?url="

def call_whitelisted_api(endpoint: str, api_key: str) -> dict:
    """Route request through CORSPROXY for stable outbound IP."""
    response = requests.get(
        f"{PROXY}{requests.utils.quote(endpoint, safe='')}",
        headers={
            "Authorization": f"Bearer {api_key}",
            "Content-Type": "application/json",
        },
    )
    response.raise_for_status()
    return response.json()

# External API only sees CORSPROXY's static IP
data = call_whitelisted_api(
    "https://api.partner.com/v1/data",
    os.environ["PARTNER_API_KEY"],
)

// Go — Fixed IP outbound via CORSPROXY
package main

import (
  "fmt"
  "io"
  "net/http"
  "net/url"
)

const proxy = "https://corsproxy.io/?url="

func callWhitelistedAPI(endpoint, apiKey string) ([]byte, error) {
  req, _ := http.NewRequest(
    "GET",
    proxy+url.QueryEscape(endpoint),
    nil,
  )
  req.Header.Set("Authorization", "Bearer "+apiKey)
  req.Header.Set("Content-Type", "application/json")

  resp, err := http.DefaultClient.Do(req)
  if err != nil {
    return nil, err
  }
  defer resp.Body.Close()
  return io.ReadAll(resp.Body)
}