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Add, change, or remove HTTP request headers on the sites you choose. Runs locally, no account, no tracking. HeaderNinja lets you add, change, or remove HTTP request headers on the sites you choose, straight from the Chrome toolbar. No proxy, no DevTools, no account. TYPICAL USES • Send an Authorization or bearer token to an API you are testing • Set a custom User-Agent to see how a site behaves on other devices • Pass a feature flag or debug value to a staging server • Reproduce a bug that only appears with a specific request header • Try out CORS, caching, or content-negotiation behaviour by hand FEATURES • Add or override any request header by name and value • Optional URL filter per rule, so a value applies only where you want it • One-click switch to enable or disable every rule at once • Rules are saved locally and survive browser restarts • Small, focused popup with no sign-up, paywall, or upsell HOW IT WORKS HeaderNinja uses Chrome's declarativeNetRequest API (Manifest V3), so your rules are applied by the browser's own network layer without the performance and privacy cost of the older blocking webRequest approach. Everything is stored in your browser. PRIVACY • No tracking, analytics, or telemetry • No data leaves your browser • No remote code • Two permissions only: declarativeNetRequest to apply your rules, and storage to save them Built for developers, QA engineers, and anyone who tests APIs. Free and open source under the MPL-2.0 licence.
Sep 6, 2026
rating_count is the Chrome Web Store ratings count, not a written-review count.
Media assets
Screenshots and videos on the listing.
Has promo video
Whether the listing includes at least one video.
Languages
Declared language locales.
Developer website
Listing exposes a developer website URL.
Contact email
Listing exposes a contact email.
Keyword in name
Case-insensitive substring match in the name.
Keyword in description
Case-insensitive substring match in the description.
Keyword occurrences in description
Count of case-insensitive occurrences in the description.
Category user-count percentile
Share of same-category extensions with fewer users (null if unknown).
These are transparent listing completeness / keyword signals, not a prediction of Chrome Web Store search ranking.