Gerolamo — Browser Cardano Node
Your browser becomes a Cardano node. Syncing the Preprod testnet via native Ouroboros mini-protocols — no REST API, no centralized backend.
Traditional Wallet
SINGLE POINT OF FAILUREGerolamo (This Page)
NO SINGLE POINT OF FAILUREOuroboros Protocol Log
0 entriesPress "Start Preprod Sync" to begin syncing via Ouroboros ChainSync.
Gerolamo is an alternative Cardano node implementation written entirely in TypeScript by HarmonicLabs. Unlike the official Haskell cardano-node, it runs on the Bun JavaScript runtime.
The key library — @harmoniclabs/ouroboros-miniprotocols-ts — implements the Ouroboros networking protocols (Handshake, ChainSync, BlockFetch) in a transport-agnostic way. It works over TCP (Node.js/Bun) or WebSocket (browser).
This page loads that library directly in your browser. When you click "Start", your browser opens a WebSocket to a transparent TCP bridge, then speaks the native Ouroboros protocol to a Cardano Preprod relay — exactly what a full node does.
How This Page Works
Your Browser (= Gerolamo Node)
Runs @harmoniclabs/ouroboros-miniprotocols-ts. Executes Handshake → ChainSync → BlockFetch. Parses real CBOR-encoded blocks.
WebSocket ↔ TCP Bridge
Transparent byte-level proxy. Does NOT interpret protocol data. Just converts WebSocket frames ↔ TCP stream.
Cardano Preprod Relay
Standard Cardano relay node on the Preprod testnet P2P network.
Why This Matters
- ✓No API keys. No rate limits. No single point of failure.
- ✓If this bridge goes down, connect to any other Ouroboros-compatible WebSocket relay. Your browser runs the protocol — the infrastructure is interchangeable.
- ✓This is what "decentralized" actually means: the client doesn't depend on any specific server to access the blockchain.