headerMod — Modify HTTP Headers

headerMod is a developer tool that lets you add or modify HTTP request headers. • Turn rules on/off globally or one by one • Optional URL filter per rule • Grant access per website, or add an API host manually (you stay in control) • Warning when a rule's URL filter targets a host that is not yet authorized • See active rule count and authorized site count at a glance on the toolbar icon • Everything is stored locally in your browser headerMod does not collect, upload, or track your data. There is no account and no analytics.