simple-modify-headers

The extension rewrite the header (request or response) based on a rules table. It 's possible to add, modify or remove header fields for a choosen url pattern. It's possible to import/export the configuration
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Simple Modify Headers is a powerful Chrome extension designed to rewrite HTTP(S) request and response headers with ease. Using a customizable rules table, users can add, modify, or delete headers selectively based on URL patterns. The extension supports exporting your configuration to a JSON file and importing from files—including compatibility with the widely-used ModifyHeaders plugin format.

This open-source tool, licensed under the Mozilla Public License 2.0, empowers developers and testers to control HTTP headers efficiently, enhancing debugging, privacy, and functionality testing. For more information and source code access, visit the GitHub repository.

Manifest V2
By:
Didierfred
Daily users:
4,687+ -54
Rating:
4.61
(33) 0.10
Version:
1.9.0 Last updated: 2024-07-14
Version code:
5775251
Creation date:
2018-01-09
Risk:
High risk impact Moderate risk likelihood
Permissions:
  • storage
  • webRequest
  • webRequestBlocking
  • <all_urls>
  • tabs
Size:
151.86K
URLs:
Website
Full description:
See detailed description ⏷
Source:
Firefox Browser Add-ons
Updated:
a day ago

Ranking

# 1,201 ▼ 10
Other rankings
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Other platforms

simple-modify-headers (v1.9.0)
20,000+ 4.50 (20)

User reviews

Users appreciate simple-modify-headers for its simplicity, reliable addition of request headers, and clean interface. The extension is open source and free. However, multiple users report that it does not modify response headers, struggles with URL part modifications, and sometimes fails to work on certain URLs, especially localhost. It also lacks features for easy site blocking and run-time feedback, which affects usability. Overall, it works well for basic header modifications but has limitations that impact advanced use cases.
Pros
  • Simple and straightforward to use
  • Effective in adding request headers
  • Modern and clean user interface
  • Open source and free with no hidden functions
  • Compatible with older versions of Firefox
Cons
  • Does not support adding or modifying URL parts as expected
  • Fails to modify or add headers in some cases (e.g., on localhost or specific domains)
  • Cannot modify response headers like Content-Security-Policy
  • Lack of feedback or indication when the extension is active or which rules are applied
  • Requires always showing on toolbar; no convenient quick add for sites to block
Recent reviews
by Firefox user 18984284, 2025-05-09
Does nothing, headers are not added for 127.0.0.1:8080/*
by Firefox user 14492264, 2025-05-09
by Firefox user 18941059, 2025-04-15
View all user reviews ›

Extension safety

Risk impact

simple-modify-headers requires some sensitive permissions that could impact your browser and data security. Exercise caution before installing.

Risk impact analysis details
  • Critical Allows access to all websites, posing a significant security risk as it can monitor and modify data from any visited site.
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  • High ****** *** ********* ** ******* *** ******* ******* ** ****** *** *** ******** ******
Risk likelihood

simple-modify-headers is probably trust-worthy. Prefer other publishers if available. Exercise caution when installing this add-on.

Risk likelihood analysis details
  • High This extension has low user count. Unpopular extensions may not be stable or safe.
  • Low **** ********* *** ******* **** **** * ****** **** ***** ******** *** **** ****** ** ** ****** *** *****
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Upgrade to see full risk analysis details

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