Header Override

What is Header Override?

Header Override is a free browser extension for changing HTTP headers and cookies without editing application code. Developers, QA engineers, and support teams can create rules in Chrome, Edge, or Firefox and save them in local profiles.

Key Features

• Modify headers with ease: Users can add request headers and response headers and request cookies and response cookies through extension popup which provides an easy-to-use interface.

• Scope rules by URL: You can control rule execution by using URL filter patterns which browsers support to restrict rule effects to your desired web requests.

• Comprehensive cookie control: Users can define response cookie attributes which include Domain and Path and SameSite and Lifetime and Max-Age and Secure settings.

• Profile management: Maintain separate local rule profiles which function as your development and staging and QA environments and testing setups and account management system.

• Import and export: Users can transfer their chosen profiles between different browsers through the built-in JSON import and export feature.

• Rule organization: Users can control rules through activation and deactivation and removal and comment-based annotation which improves both documentation and operational processes.

• Cross-browser support: Works seamlessly in Chrome, Edge, and Firefox.

Who is it for?

Header Override serves developers who require to verify authorization headers and debug API calls and test website reactions to various header information. QA engineers use scoped local rules to duplicate customer-specific headers and cookies while they establish temporary QA rules and test UI flows by activating backend flags. Support teams can switch between client, environment, or test-account setups quickly using saved profiles.

Why Header Override stands out

Header Override serves as an browser extension which provides users with a compact privacy-based workflow instead of a full-fledged debugging system. The extension operates as a self-contained system which prevents any information from leaving the user's computer system. Your browser extension storage saves rules but it prevents them from ever reaching a server. The system operates without analytics and tracking and remote code execution and external service requirements. Request values are sent only to matching destinations, while response values are applied only to matching responses.

The project source is public on GitHub, allowing for direct review, issue reports, and community contributions. Header Override provides optimal solutions for teams which need privacy protection and straightforward development operations through its open system and its lightweight operational design.

Common use cases

• Send debug headers to staging APIs without touching application code.

• Reproduce customer-specific headers or cookies with scoped local rules.

• Toggle backend flags while testing UI flows in your browser.

• Switch between client, environment, or test-account setups with profiles.

• Document temporary QA rules before removing them.

Header Override enables users to quickly answer questions about API debugging and authentication testing and client simulation through a local solution which protects user privacy without requiring code modifications or extensive configuration.