> ## Documentation Index > Fetch the complete documentation index at: https://docs.openheaders.com/llms.txt > Use this file to discover all available pages before exploring further. # Extension quick start > Install the Open Headers extension from your browser's store and put your first rule on live traffic. By the end of this page the extension is installed and a rule of yours is modifying live browser requests. The extension is the full toolkit, standalone — no other install required. ## Install Install from your browser's store: Pin the extension to your toolbar — the icon is also where the popup opens from and where the badge shows rule activity. ## Create your first rule 1. Open the popup and go to **Rules**. 2. Create a rule — a request-header rule is the classic first one: pick the header name and value, and scope it to the sites it should apply on. 3. Enable the rule and load a matching page. The **Network** panel shows the request with your modification applied. Rules cover nine types over live traffic — headers, redirects, response overrides, and more — and apply through the browser's own `declarativeNetRequest` engine, so they work even while the popup is closed. ## What else is in the box Everything runs locally in your browser: a DevTools-grade network panel, a full API client (HTTP, GraphQL, gRPC, WebSocket, OAuth 2.0), workflows, an encrypted vault, and multi-workspace collaboration. Pair it optionally with the [desktop app](/quickstart/desktop) for git-backed sync, dynamic value sources, and a local proxy — the extension connects to it automatically when both run on the same machine.