arpeesee is a Chrome extension + desktop app that intercepts and decodes Connect RPC and gRPC-web traffic. It shows you field names instead of binary garbage.
No account. No email. No credit card. Genuinely. Or sign up, I guess →
Four steps. No wizard. No onboarding email sequence.
Download arpeesee for macOS or Linux. It runs in the background, decodes your traffic and gives you a UI to inspect it.
Add the Chrome extension. It intercepts gRPC-web and Connect RPC calls in your browser and forwards them to the desktop app.
Tell arpeesee where your .proto files live. A local directory, a git repo or a GitHub repo. It builds a schema registry from whatever you point it at.
Open any app that makes RPC calls. Watch them appear, decoded, in the arpeesee panel. Inspect requests, responses, latency and gRPC status codes.
Everything runs on your machine. Nothing leaves.
We're not going to say "supercharge" or "10x" anything. Here's what it does.
Maps raw proto bytes to field names and values using your local schema. Supports grpc-web, connect-proto, connect-json and grpc-web-text.
Your API calls never leave your machine. No cloud decode service. No analytics. No phoning home. The binary doesn't even ask for your name.
Point at a local directory, a git repo or a GitHub repo. Supports buf workspaces. Refreshes when your schemas change.
Exposes a Model Context Protocol server so Claude, Cursor or any MCP-compatible agent can inspect your captured calls. You approve every connection.
We made arpeesee because debugging gRPC-web calls was annoying. Chrome DevTools shows you binary. The network tab shows you noise. We wanted to see actual field names.
So we built it. Now it's yours.
There's no SDK to install. No middleware to register. No handler to wire up. You don't touch your app at all. The Chrome extension intercepts calls at the network layer and arpeesee decodes them on your machine using the proto files you already have.
It doesn't care how your frontend is structured. One app, fifty micro-frontends, a monorepo, a mess. Doesn't matter. If it makes RPC calls, arpeesee sees them. The only thing it needs is your .proto files.
No subscription. No freemium tier. No features gated behind a paid plan. No investor to explain the monetization strategy to.
It's just a developer tool. We needed it. Maybe you do too.
We agonized over this. Here's what we came up with.