Modify HTTP Headers (HTTP Header) - FlexHeader icon

Modify HTTP Headers (HTTP Header) - FlexHeader

by Harrison Deo · harrisondeo.me.uk · Developer Tools
Established publisherManifest V3 Free
View in Chrome Web Store Data as of 15 Oct 2026

Add, modify & delete HTTP request/response headers with URL & regex rules. Open-source, private, no data collection

Users
7,000
+1,000 in 30 days
Rating
4.9 / 5
+0.01 in 30 days
Ratings
30
+1 in 30 days
Store rank
#12K
#10K among extensions
Version
1.11.2
updated 11 Sep 2026

Users

monthly, 3 years
03,5007,000Aug 2023Apr 2025Oct 2026
Latest, 15 Oct 2026: 7,000 usersMove the mouse over the chart for any month

Ratings count

monthly, 3 years
01530Aug 2023Apr 2025Oct 2026
Latest, 15 Oct 2026: 30 ratingsMove the mouse over the chart for any month

The Chrome Web Store rounds user counts down to the leading digit, so the user line moves in steps. The ratings count is exact and is the better signal of real adoption.

About Modify HTTP Headers (HTTP Header) - FlexHeader

FlexHeaders makes it easy to modify HTTP request and response headers directly from your browser. Create pages for different websites, environments or scenarios; add regex or url filters and pause pages at any time. Key Features: -🛡️ Add, Modify and Remove HTTP headers for any request -♾️ Sync functionality for cross browser syncing (chrome profile) -🔧 Export/Import feature to share with colleagues or friends -🔓 Open Source, you can find the source code here: https://github.com/harrisondeo/FlexHeader -🔀 Import ModHeader export JSON allowing you to get back working easily. -💼 Enable multiple pages at same time -🌐 URL & Regex filtering for all pages -🔎 Header searching -📝 Header comments so you can annotate -✨ Autocomplete for common header names -⏫ Sort headers by name, comment or value -↩️ Undo and redo changes -🌙 Light & dark mode -↔️ Collapsible sidebar Advanced features include being able to drag & drop reorder headers, set the font size within the popup, enable/disable all headers with 1 button, sync config across same chrome profile on different browsers/computers. Edit HTTP Headers easily with FlexHeaders, an open-source Chrome extension designed for developers and privacy-conscious users who need to modify or edit HTTP request headers on the fly.

Growth

WindowUsersChangeRatingsRating
7 days0+0.0%00.00
30 days+1,000+16.7%+1+0.01
6 months+6,000+600.0%+17+0.18
1 year+6,015+610.7%+22−0.13

Chrome Web Store search rankings

Where Modify HTTP Headers (HTTP Header) - FlexHeader appears when people search the store, with the 30 day change
Search phrasePosition30 days
modify#13+3
header#35+3

Version history

38 versions recorded
1.11.211 Sep 2026
1.11.126 Aug 2026
1.11.022 Aug 2026
1.10.029 Jul 2026
1.9.628 Jul 2026
1.9.423 Jul 2026
1.9.523 Jul 2026
1.9.122 Jul 2026

Details

Category
Developer Tools
First seen
29 Aug 2023
Size
188 KB
Languages
en-GB
Pricing
Free
Support
github.com
Extension ID
gffpeamhhldhibdngenbfciboinanppf

Permissions and risk

Moderate riskimpact 2, likelihood 2
Permissions
storagedeclarativeNetRequest
Site access
<all_urls>
Can read and change data on every website you visit.

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