How to Route Traffic to Multiple Microservices with AWS API Gateway

I recently set up AWS API Gateway to forward requests to two different microservices. Here’s how I did it step by step 👇

The Goal

I had two backend services behind their own load balancers:

• User Service: http://user-lb-1148255498.ap-south-1.elb.amazonaws.com
• Order Service: http://order-lb-1634505146.ap-south-1.elb.amazonaws.com

I wanted:

1. /api/users → User service
2. /api/orders → Order service
3. Any extra path after these (like /health) should also go to the correct service.

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Step 1: Create an HTTP API

1. Go to API Gateway → HTTP API → Create API.
2. Choose Manual route configuration.
3. Give it a name like MicroserviceGateway.
4. Choose HTTP integration.
5. Add both services one by one:

User Service Integration:

• URL: http://user-lb-1148255498.ap-south-1.elb.amazonaws.com
• Proxy URL: http://user-lb-1148255498.ap-south-1.elb.amazonaws.com/{proxy}

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Step 2: Add Routes and Connect Integrations

For each service, create two routes — one for the base path and one for everything after it.

User Service

• /api/users → Integration: User LB
• /api/users/{proxy+} → Integration: User LB

Note: {proxy+} means it will forward any subpath after the main route to the backend. For example, /api/orders/health goes to /health on the Order service.

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Step 3: Deploy the API

1. Go to Deployments → Create Deployment.
2. Create a stage named prod.
3. Click Deploy.

You’ll now get a single URL like this: https://abc123xyz.execute-api.ap-south-1.amazonaws.com/prod

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🔍 Step 4: Test the Setup

Try calling these endpoints to confirm they route correctly:

• /prod/api/users → goes to User service
• /prod/api/users/health → goes to User service /health
• /prod/api/orders → goes to Order service

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💡 Key Tips

• Always add both: A base route and a proxy route.
• Use {proxy+}: To catch all subpaths effectively.
• Set method = ANY: To allow GET, POST, PUT, etc., to flow through.
• Test Backends First: Confirm your LBs are reachable before connecting them.

✅ That’s it! Now you have a single API Gateway URL that routes traffic cleanly to multiple microservices.