API Key security: why should it never be placed on the Frontend?

Placing an API Key in the Frontend is one of the most common and dangerous security mistakes. This article explains why and how to properly protect applications.

Frontend is a trustless environment

Anything running in a browser can be read. Keys placed in the Frontend, even if obfuscated, can still be extracted and abused.

Solution: server-side proxy

Place the key in the backend and let the frontend call through a proxy layer with authentication. You control access rights, rate limit and audit log.