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
Latest, 15 Oct 2026:7,000 usersMove the mouse over the chart for any month
Ratings count
monthly, 3 years
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
Window
Users
Change
Ratings
Rating
7 days
0
+0.0%
0
0.00
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