Understanding API Security Expectations in Frontend Development: Clarifying Best Practices

In modern web development, safeguarding sensitive information such as API endpoints and keys is a common concern—especially when working on frontend applications. Recently, I encountered a scenario where my manager and senior DevOps engineer insisted on “hiding” API URLs and keys within a React-based frontend project. This post aims to shed light on the realities of frontend security and best practices for managing API secrets.

The Situation

As a React intern, I was asked to ensure that API endpoints and keys are not visible in the browser’s developer tools—specifically, the Network or Sources tabs. The goal was to prevent users from viewing these URLs or secrets directly through browser inspection tools.

However, from my understanding and experience, any code or data included in the frontend—be it JavaScript files, HTML, or network requests—is inherently accessible to end users. This includes the API URLs invoked by the frontend and any embedded API keys used for identification or other purposes.

Online Insights and Clarifications

Many developers and security experts agree that it is not feasible to fully conceal API URLs or keys on the client side. Obfuscation techniques can be employed, but they are not foolproof and should not be mistaken for real security measures. Ultimately, sensitive data such as API secrets should not be transmitted or stored within client-side code.

Best Practices for Securing API Communication

1. Use Server-Side Endpoints (Backend for Frontend – BFF):
   When security is paramount, routing API requests through a dedicated backend server is recommended. The backend can store secrets securely and handle business logic, ensuring that API keys never reach the browser. This setup also allows for better control and security.

2. Implement Proxy Servers:
   If directly accessing your backend API from the frontend is necessary, consider deploying a proxy server. The proxy acts as an intermediary, hiding actual API URLs from clients and managing authentication securely.

3. Proper Cookie Handling:
   Sensitive session identifiers should be protected using cookie attributes like HttpOnly, Secure, and SameSite to prevent client-side scripts from accessing them. Managing these attributes on the server side reduces the risk of exposure.

4. Minimize Exposure of Unnecessary Data:
   Design your API to expose only what’s needed—avoid sending sensitive information or secrets unless absolutely necessary. Use token-based authentication mechanisms, such as OAuth or JWTs, which are more secure than embedding static API keys.

Addressing the Specific Requests

My DevOps team’s