screenshotModify Header Value (HTTP Headers)  |  Download Add, modify or remove a header for any request on desired domains.

Some of the important features of the Modify Header Value (HTTP Headers) addon are listed below. This is followed by an overview of this addon. This summary contains few words about the addon, its function, and its features. Next is FAQ, this section is useful to get information about how this addon works in your browser. If you couldn't find a specific answer, please fill the bug report form on this page or the contact form on the homepage to let us know about your question. Following the FAQ, is the bug report form. It is designed to collect user feedbacks and bugs about this addon. Users can suggest improvements or feature requests through this form too. The next section is for submitting comments about this addon which uses the Facebook comments plugin. The last section is dedicated to reports submitted through the GitHub website. We hope the information provided on this page, could help you get all the basics you need about this addon and enable you to have a better experience with Modify Header Value (HTTP Headers).

In short, Modify Header Value (HTTP Headers) can add, modify or remove a custom (HTTP request header) for any request on desired url(s). This addon is very useful if you are an app developer, website designer, or if you want to test a particular header for a request on a website. Please check the YouTube tutorial below to get an idea of how this addon works in your browser. If you want to contribute to the developement of this addon, please fork it on GitHub, and push your changes to a named branch. Moreover, you can review all the comments made on GitHub commits.

7 Reasons to Use Modify Header Value (HTTP Headers)

  • Add, modify or remove a custom header value for any request on desired domains.

  • For a complete list of HTTP headers, please take a look at the list of HTTP Header Fields in Wikipedia.

  • Clicking on the Toolbar icon allows you to disable the addon.

  • Each header item has several options to adjust (see options page for details)

  • You can add several header items and active or inactive them separately.

  • An example in the options page shows how to add a custom header.

  • This addon is available for Google Chrome, Firefox and Opera.

YouTube Tutorial

This video gives you an idea of how the extension works in your browser.

Matched Content


  • The amazing thing about the internet is that it puts the entire world at our disposal without having to go into the details of how everything works behind the scenes. However, there are people who need the knowledge on how the internet works behind the scenes, it is their bread and butter after all. Every time we write the URL of a website in the address bar, one HTTP request is sent to the server hosting the website after passing through a swarm of devices. These requests contain many entries so they're saved in different HTTP headers for the receiving server to instantly recognize the information. Modern browsers such as Google Chrome and Mozilla Firefox are used by a large majority of geeks, programmers and other people involved in the world of information technology who often play with these HTTP header values so that is where this add-on comes into play - to make the task of changing HTTP header fields simple. The name of the add-on is Modify Header Value (HTTP Headers). Even though the working is very simple but the options it offers are very detailed for example you can enable or disable the add-on by a single click on its icon in the toolbar.

    It has made the function of adding, modifying or removing a custom header for any domain which is useful for website and app developers as it allows them to easily test the response for a particular custom header on any specific website. It is also useful for advanced users as they can see the behavior of a website by tinkering with these values. Users can also use this add-on to access the websites in their mobile view by simply changing the values in the "User-Agent" header to those belonging to a smart-phone. The level of customization this tool provides, the possibilities are virtually endless.

Frequently Asked Questions

  • 1. What is Modify Header Value?

    With Modify Header Value you can add, modify or remove a custom "HTTP request header" for any request on desired url(s). This addon is very useful if you are an app developer, website designer, or if you want to test a particular header for a request on a website. Modify Header Value allows you to easily change an HTTP request header sent to any web server. For a complete list of HTTP headers, please take a look at the list of HTTP Header Fields in Wikipedia.

  • 2. How does Modify Header Value works?

    In order to start working with modify header value, open the options page and read the tutorial available at the top of the page.

  • 3. How can I download the source code for Modify Header Value (HTTP Headers)?

    To download the source code for this extension from Chrome Web Store, it is recommended to use Extension Source Downloader. With this addon, you can download the source code as a ZIP or CRX format to your machine. If you want to download the source code from the Firefox addons store, please open the firefox download link (if available) in the Firefox browser and then right-click on the - Add to Firefox - button and select - Save Link As... - item. Choose the destination folder on your machine and then save the file in XPI format. You can then rename the XPI format to a RAR or ZIP file. Some extensions may have a GitHub repo address, which you can use to download the source code as well. But, it may not be the latest version of the addon. Therefore, downloading the source code from the official web stores is the best option as it always gives you the latest version of the addon.

  • 4. What options are available for a custom header?

    There are 11 options available to adjust for a header. Option (1) is the header number. Option (2) is where you put desired URL. If you check Option (3), the header will be applied to all domains matching the domain for the given URL. Option (4) applies the Header to all URLs whose Tab (or Top level) URL is the domain matching the given URL. Option (5) is the Header name. If you check Option (6), the header will be added to the current URL. Likewise, if Option (7) is checked the header, if matched, will be modified with the new value. Option (8) is to remove the given header, if existed, from the given url-request. Option (9) is for the header value. Option (10) is to activate or inactivate the header, yellow color indicates an active and gray color indicates an inactive header (clicking the button will swap the colors). Option (11) is to permanently delete a header item.

  • 5. How to disable Modify Header Value?

    In order to disable this addon, there are two options available. First, you can click on the toolbar-icon and disable the addon once the icon color is white. Or you can disable the addon from the browsers extension page.

  • 6. How can I print the headers and other info to the console?

    In the latest version of modify header value addon, the option to print all the info to the console is available. Just open the options page and check the related filed to print everything to the console. In order to open the console in Google Chrome and Opera, first go to the extensions page "chrome://extensions/", then find this addon and click on the "background.html" hyper-link. Once a new page is open, click on the console tab to view all the prints. For Mozilla Firefox browser, within a Firefox tab, simply hold "Ctrl + Shift + J" keys to open the console. Alternatively, you can go to the tools tab, then hover on to the web-developer item and click on the browser-console item. Within the console you can see all the prints from Modify Header Value addon.

  • 7. Is there any toolbar UI to open the options page or turn the addon ON or OFF?

    Yes, in the latest version of the addon, there is a UI to perform this tasks. Simply click on the addon icon to open the UI. Within the UI you will see three function.

  • 8. Where can I find the privacy policy for Modify Header Value (HTTP Headers)?

    Please read the privacy policy for this extension here.


Reporting Bugs

Your feedback goes a long way towards making this addon even better. With this feedback and bug report form, you can report bugs or suggest features/enhancements for the functionality or performance of this addon. Please note that this form will be sent to the developer(s) of this addon. You will not get an immediate or personal response at the moment. However, the developer(s) may contact you through the email address provided in this form for further clarifications or to request additional information regarding the reported bug(s).

If you want to rate or write a review for this addon in the official webstore, please press the - Rate this addon - button below.

Please enter the name of the extension (addon).

Please enter the current version of the extension.

Please be as specific as possible. Basically, describe what happened, what you were doing when it happened, and why you think it is a problem.

Describe the step-by-step process required to reproduce the issue you are reporting. Be specific when describing these steps by providing as much detail as possible.

Please try to leave a link to a screenshot for the specific bug or error report.

Please enter your operating system.

Please enter your browser and its current vesrion.

Please enter your email address.

Reviews | Discussions

Please note: keep these reviews/discussions clean, and avoid the usage of derogatory or inappropriate language or terminology in references to individuals or groups based on race, national or ethnic origin, color, religion, age, gender, etc. Do not submit bugs in your reviews, use the above bug-report section instead. Also, never post any personal information in these reviews.