
Requestly
Header Editor
RequestHeaders.com
VibeHeader
HTTP Header Live
Modify Header Value (HTTP Headers)
Header Override
A local-first ModHeader alternative: rewrite HTTP request & response headers via Chrome's native declarativeNetRequest. No backend, no account, no telemetry.
Requestly
Charles Proxy
Fiddler
HTTP Toolkit
Header Editor
Proxyman.io
EditThisCookie
Free browser extension to modify HTTP request and response headers. No sign-up. Works on Chrome, Firefox, and Edge.

Which is more popular?
Website, pricing, platforms and company facts side by side.
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modheader
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| Website | headerflex.app | app.modheader.com |
| Listed in |
What each product offers, as listed by its team.

Possible disadvantages
Possible disadvantages
How often each product is chosen within a category, 0–100% relative to the other.

Share your experience with using HeaderFlex.app and modheader. For example, how are they different and which one is better?
External articles and on-site reviews we used to compare the two products.

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On the pricing front, Requestly strikes a balance between affordability and functionality. It is an open-source tool, offering freemium to individual developers and affordable pricing plans for team collaboration. We...
When comparing HeaderFlex.app and modheader, you can also consider the following products.

Add custom HTTP request headers to any site. Set Authorization tokens, override Content-Type, inject debug headers per URL pattern. declarativeNetRequest. Free: 5 rules, Pro: unlimited.
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HTTP proxy / HTTP monitor / Reverse Proxy
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HTTP Header Checker Tools
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Fiddler is a debugging program for websites.
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An open-source ModHeader alternative trusted by 10,000+ developers. Edit and share headers with Profiles, URL filters, and a built-in tester.
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