How to Build an AWS HTTP API Proxy Gateway: Secure Your Keys
By Braincuber Team
Published on March 21, 2026
We just audited a $4M D2C brand that hardcoded their FedEx and Klaviyo API keys directly into their React frontend. Anybody with Chrome DevTools could steal their keys, rack up $10,000 in fraudulent shipping labels, and delete their entire customer database. If your frontend talks directly to third-party services, you are fully exposed. You need an API proxy gateway. A proxy sits between your browser and the target API, injecting your secret keys server-side so the client never sees them. This guide shows you exactly how to configure an AWS HTTP API to proxy these requests cheaply and securely.
What You'll Learn:
- Why AWS HTTP API is significantly cheaper than REST API
- How to configure dynamic path routing variables
- The parameter mapping pitfall that breaks 90% of new gateways
- How to securely append API keys to outgoing requests
- Attaching Google Auth JWT Authorizers to lock down endpoints
HTTP API vs REST API: The Cost Truth
AWS offers two types of API Gateways. REST API gives you granular control (per-client throttling, brutal request validation). HTTP API gives you speed and massive cost savings. Unless you are building the next Stripe, you do not need the bloated overhead of REST.
| Feature | AWS HTTP API | AWS REST API |
|---|---|---|
| Pricing per Million Requests | Roughly $1.00 | Roughly $3.50 (350% more expensive) |
| JWT Authorization | Native Support | Requires Custom Lambda Authorizer |
| Endpoint Type | Regional Only | Edge-Optimized Available |
| Setup Complexity | Minimal configuration, fast deployment | Heavy configuration, requires steep learning curve |
Mask Target URIs
If competitors know exactly which backend services you route data to, they can reverse-engineer your tech stack. A proxy hides the final destination completely.
Inject Secret Keys
The browser asks the proxy for data. The proxy appends your API token to the header, safely on the AWS server, and asks the third party. Your keys never touch the client.
Step by Step Implementation Blueprint
Create the Gateway and Define Routes
Navigate to API Gateway in AWS. Click Build on HTTP API. Routes are the path endpoints that correspond to a resource. You can send dynamic values by placing curly braces around the path variable. Example: /getshipping/{zipcode}. You cannot put query parameters directly in the route definition.
Add the Target Integration
Click on your new route and hit Attach integration. Select HTTP URI. Here is the trap: do not paste the entire URL string with parameters into the Target URI box. If you type http://api.vendor.com/search?q={zipcode}, AWS will literally send the string "{zipcode}" instead of the actual number. Just paste the base domain: http://api.vendor.com.
Mapping Rule Danger
Do not ignore parameter mapping. If you define the full path in the target URI, AWS treats it as a static string. Your query won't execute, and you will spend 3 hours crying while debugging your frontend code. Follow the mapping instructions below exactly.
Configure Parameter Mapping Rules
Below the integration details, you will find Parameter Mapping Rules. Select All incoming requests. You must explicitly tell AWS to overwrite the incoming path and append the query string variables holding your dynamic values.
# Action 1: Modify the path
Modify Type: Overwrite
Parameter to modify: path
Value: /api/v1/search // Note: Statically typed suffix path
# Action 2: Append dynamic query string
Modify Type: Append
Parameter to modify: querystring.q_zipcode
Value: $request.path.zipcode // Note: Pulls the '{zipcode}' variable from your initial incoming request
Attach JWT Authorizers (Optional but Recommended)
If you only want logged-in users calling this proxy to prevent DDoS attacks against your wallet, go to Authorization and create a JWT Authorizer. Feed it your Issuer URL (e.g., https://securetoken.google.com/your-project). The API Gateway will natively bounce any request lacking a valid bearer token before it ever hits your target API.
Frequently Asked Questions
Can I append my secret API keys inside the Parameter Mapping rules?
Yes. Use the Append modifier, set the parameter to querystring.api_key (or whatever your target requires), and hardcode your secret token as the static value. The client will never see it.
Why is AWS passing literal strings instead of my variables?
Because you defined the variable directly in the target URI box inside the Integration window. You must leave the Target URI as a bare domain and push the variables through the parameter mapping tool using the $request syntax.
Is HTTP API Gateway really that much cheaper than REST API?
Yes. HTTP APIs are up to 71% cheaper than REST APIs on AWS. You only pay roughly a dollar per million requests, completely crushing the cost structure of most third-party enterprise proxy services.
Can I pass multiple variables in an HTTP API Proxy?
You can map multiple query parameters effortlessly, but mapping more than one path variable dynamically in the outgoing request often fails in HTTP API natively. Limit yourself to one path parameter and lean heavily on query strings.
Do I need to write a Lambda function for AWS HTTP API Authorization?
No. If you use a JWT provider, the HTTP API has native support for validating tokens. You simply give it the Issuer URL, and AWS validates the cryptograph before forwarding the payload.
Is Your Frontend Leaking API Credentials?
If you let your intern build your shopping cart integrations, there is a 95% chance they shoved your FedEx keys straight into the public browser scope. That is how entire companies get bankrupted overnight. We audit architecture and lock down endpoints tight. Stop gambling with your infrastructure. Let us examine your stack before the bots scrape your tokens.