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Static IP guide

Making API requests with a static IP from a Node app on AWS Lambda

The AWS-native way to give Lambda a static IP is a VPC with a NAT Gateway and Elastic IP — infrastructure, hourly cost, and data processing fees, all to fix an address. A Fixie HTTP/S proxy replaces that with a single FIXIE_URL environment variable on the function, and axios calls exit from two permanent IPs.

RuntimeNode.js and JavaScript
PlatformAWS Lambda
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 Node.js to route outbound traffic through Fixie before connecting to API allowlisting.

Set up Fixie on AWS Lambda

Create a Fixie HTTP/S proxy in the Fixie dashboard. Copy the proxy value into AWS Lambda environment variables as FIXIE_URL, and copy the outbound IPs into the destination allowlist.

Set an AWS Lambda environment variable

aws lambda update-function-configuration \
  --function-name YOUR_FUNCTION \
  --environment "Variables={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

const axios = require('axios');

const fixieUrl = new URL(process.env.FIXIE_URL);

axios.get('https://api.example.com/data', {
  proxy: {
    protocol: 'http',
    host: fixieUrl.hostname,
    // URL drops default ports, so fall back to 80 for Fixie's standard proxy port.
    port: Number(fixieUrl.port) || 80,
    auth: {
      username: fixieUrl.username,
      password: fixieUrl.password,
    },
  },
}).then((response) => {
  console.log(response.status);
});

Good to know

  • Parse FIXIE_URL and build the axios config outside the handler so warm invocations reuse it.
  • The function needs no VPC attachment at all — that is the point; it keeps cold starts fast and networking simple.
  • Fixie publishes a complete Lambda example app on GitHub (usefixie/aws-lambda-example-app) covering SAM and Serverless Framework configuration.

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 Node.js app on AWS Lambda.
  4. Run a small connection test before sending production traffic.

Related guides

Related docs