Quartermaster Lens
A read-only browser extension that lets you test-drive the Quartermaster x402 API from your toolbar — ask the Router which tool fits a goal, inspect any page as an x402 endpoint, search the Bazaar, and preview payment challenges.
It is not a wallet. No keys, no seed phrases, no signing, no custody, no automatic payments. Every action is a read-only request.
Firefox
One-click install · signed by Mozilla
Install for FirefoxClick to install. If Firefox blocks it, choose Continue to Installation, then Add.
Chrome · Edge · Brave
Load unpacked (developer mode)
Download source (.zip)Unzip, open chrome://extensions, turn on Developer mode, click Load unpacked, and pick the unzipped folder. (Chrome does not allow one-click installs from outside its Web Store.)
What it does
- Ask — type a goal in plain English (“price of eth”, “audit https://api…/paid”) and the x402 Router shows which tool it would run. Free preview — nothing is paid.
- Inspect — scores whether the page you're on is an x402-payable endpoint (grade, price, network, asset, pay-to, findings), using the free x402 Inspector, with a one-click link to the full scored report.
- Bazaar — searches the live x402 Bazaar catalog of payable endpoints.
- Free tools — calls Quartermaster's free endpoints (hash, uuid, time, IP, x402 test vector). Real results, no payment.
- Preview 402 — requests a paid tool without paying, decodes the payment challenge, and hands you a copy-paste snippet to actually pay it. Nothing is paid or signed in the extension.
Safe by design
- Manifest V3, minimal permissions:
activeTab+ host access limited toquartermaster.surewhynot.appandapi.cdp.coinbase.com. - No content scripts — it never injects into the pages you visit.
- No wallet, no keys, no signing, no automatic payments. No
eval, no remote code.
More
Quartermaster home · How to pay (buyers) · Connect an agent (MCP) · All tools