Chrome extension · Developer Tools · v1.3.1

# HTTP Header Modifier {#product-title}

Add or override HTTP request headers, scoped to exactly the URLs you choose

HTTP Header Modifier is a free Chrome extension that sets HTTP request headers on the URLs you choose. Each rule pairs a URL pattern with one or more headers, such as an Authorization token or an X-Env flag, and Chrome adds them, or replaces the value the browser would have sent, on every matching request until you switch the rule off.

[4.5 from 4 reviews on the Chrome Web Store](https://chromewebstore.google.com/detail/http-header-modifier/lhjnapningfniffjhppldmpgebkdahpp?utm_source=b2bgold.app&utm_medium=referral&utm_campaign=product&utm_content=chrome/http-header-modifier&utm_term=hero) · checked 8 September 2026

[Add to Chrome](https://chromewebstore.google.com/detail/http-header-modifier/lhjnapningfniffjhppldmpgebkdahpp?utm_source=b2bgold.app&utm_medium=referral&utm_campaign=product&utm_content=chrome/http-header-modifier&utm_term=hero)

Plans

Free

Source code

[Public on GitHub](https://github.com/openhoangnc/chrome-header-mod)

Header rules scoped to a URL pattern, with the rule that matches the current page marked

## What does HTTP Header Modifier do? {#features-heading}

- **Per-URL header rules** Each rule sets HTTP request headers on the URLs that match its pattern, such as *://api.example.com/*. Give several patterns the same headers by separating them with commas.
- **Several headers per rule** Set an Authorization token and an X-Env flag in one rule. Each header is added to the request, or replaces the value the browser would have sent.
- **See what matched** A rule that applies to the page you're on is marked on this page, and the Requests tab lists recent matched requests with the headers each rule set.
- **Notes and on/off switches** Label a rule with a note, such as Staging auth, and switch it off when you're done without deleting it.
- **No account, no server** Rules are saved in Chrome's own extension storage. The extension makes no network requests of its own and has no account to create.

## When should you use HTTP Header Modifier? {#when-to-use-heading}

When a browser session needs to send a header it normally wouldn't, such as an Authorization token for an API or staging site, a feature-flag or environment header your back end reads, or a custom header a test depends on. Chrome sets it on page loads, scripts, images and API calls alike, so the page's own requests carry it too, without a proxy or a code change.

## What doesn't HTTP Header Modifier do? {#limits-heading}

It changes request headers only, by adding or overriding them. It can't remove a header, change a response header, or redirect, block or rewrite a request, so it can't make a CORS error go away, because the server's response headers decide that. Patterns use Chrome's wildcard syntax, not regular expressions, and a rule that is on applies in every tab of your Chrome profile.

## How much does HTTP Header Modifier cost? {#pricing-heading}

HTTP Header Modifier is free to install from the Chrome Web Store.

| Plan | Price | What it includes |
| --- | --- | --- |
| Free | Free | Free to install from the Chrome Web Store; Source code public on GitHub; no account and no external servers [Add to Chrome](https://chromewebstore.google.com/detail/http-header-modifier/lhjnapningfniffjhppldmpgebkdahpp?utm_source=b2bgold.app&utm_medium=referral&utm_campaign=product&utm_content=chrome/http-header-modifier&utm_term=pricing-free) |

Plans and prices as listed on the [Chrome Web Store](https://chromewebstore.google.com/detail/http-header-modifier/lhjnapningfniffjhppldmpgebkdahpp?utm_source=b2bgold.app&utm_medium=referral&utm_campaign=product&utm_content=chrome/http-header-modifier&utm_term=table), which is authoritative. Page updated 26 September 2026.

## What can HTTP Header Modifier access? {#access-heading}

The Chrome permissions in HTTP Header Modifier’s manifest, and what each one is for.

| Permission | What it allows | Why |
| --- | --- | --- |
| declarativeNetRequest | Change the headers of requests | This is how rules are applied: Chrome sets the headers itself, only on requests that match a rule that is on. |
| webRequest | See requests as they are sent | To list matched requests in the Requests tab. It only watches, and never changes a request. |
| storage | Save data in Chrome's extension storage | To keep your rules. |
| tabs | Read the address of your tabs | To mark the rules that match the page you're on and set the toolbar badge. |
| <all_urls> | Work with requests on every website | So a rule can apply to any URL pattern you type. |

It asks for no access to cookies or browsing history and runs no script inside the pages you visit.

## Frequently asked questions {#faq-heading}

[Add to Chrome](https://chromewebstore.google.com/detail/http-header-modifier/lhjnapningfniffjhppldmpgebkdahpp?utm_source=b2bgold.app&utm_medium=referral&utm_campaign=product&utm_content=chrome/http-header-modifier&utm_term=faq)

### Is HTTP Header Modifier free?

Yes. It's free to install from the Chrome Web Store, with no account and no paid tier, and its source code is public on GitHub.

### Can it remove a header or change response headers?

No. Every rule sets a request header: it adds the header, or replaces the value the browser would have sent. A header can't be deleted or given an empty value, and response headers aren't touched.

### How do I write a URL pattern?

Type it into URL match when you add a rule. *://*.example.com/* covers a site and its subdomains, *://api.example.com/* covers one host, and * matches anything. Separate several patterns with commas to give them the same headers. Chrome checks the pattern against the full address of every request, including the page's own calls to APIs.

### Where are my rules stored, and does it send data anywhere?

In Chrome's synced extension storage, so if Chrome sync is on, your rules follow your Chrome profile to your other computers. The extension itself makes no network requests. The Requests list is kept in memory: it holds the last 300 matches and empties when you click Clear or Chrome restarts the extension's background process.

### How do I check that a header was sent?

Open the Requests tab. It lists recent requests a rule matched, with the headers each rule set, and the toolbar icon shows a green tick on a tab where a rule matched. The list uses a simpler matcher than Chrome, so in rare cases it differs from what Chrome applied; what your server received is the final word.

## Install HTTP Header Modifier from the Chrome Web Store. {#install-heading}

Need help with HTTP Header Modifier? Email [chrome@afixer.app](mailto:chrome@afixer.app).

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