ModHeader review
A free Chrome extension for changing headers, managing rules and testing CSP responses.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
ModHeader is a free browser extension for developers and testers who need to change HTTP request or response headers without editing application code. It is suited to solo users and small teams checking how a site or environment responds to header changes, including Content-Security-Policy (CSP) responses. Rules can affect cookies and Set-Cookie values as well as other headers, making the extension relevant to browser-based debugging and testing workflows. Its listed platform is Chrome, so it is a focused choice for people working in that browser rather than a general-purpose request tool across platforms.
Rule controls are a central part of the product. Users can filter rules by URL, tab, window or resource type, then toggle them on or off. Multiple profiles let users keep settings separate for projects or environments, and profiles can be imported or exported. The extension can also draft and test CSP response headers, which makes it useful for checking policy changes in the browser. These capabilities give ModHeader a practical testing focus; it is not described as an application-code editor or a broader development environment.
The extension is free, requires no account, and stores profiles and settings locally on the device. That keeps setup centered on the browser, but there is no device sync, so profiles are not cloud-shared between installations. Email is the listed support channel. Choose ModHeader if you want a lightweight way to inspect and alter headers or test CSP behavior in Chrome, especially when project-specific profiles matter. Look elsewhere if you need cross-browser coverage, cloud-synced settings or a tool deployed outside the browser.
ModHeader pros and cons
- Where it wins
- Modify request and response headers, including Cookie and Set-Cookie values.
- Scope rules by URL, tab, window or resource type, and toggle them on or off.
- Manage project profiles locally, import or export them, and test CSP responses.
- Where it doesn't
- The listed platform coverage is limited to Chrome.
- Profiles and settings stay on the device, with no cloud sync.
- Deployment is limited to a browser extension rather than a standalone application.
ModHeader fact sheet, pricing and score →
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