Bitcoin Custom Signet

A custom Bitcoin Signet built for the Angor project. It provides a private, controlled test network with 30-second block times and includes a faucet for distributing test coins.

Architecture

The system has three components:

• Bitcoin Signet Node -- Dockerized bitcoind with a custom block-signing challenge and an integrated miner that produces blocks every 30 seconds.
• Faucet API -- C#/.NET 8 ASP.NET Core Web API that talks directly to Bitcoin Core via JSON-RPC to send test coins.
• Faucet Frontend -- Angular 19 SPA with Tailwind CSS that provides a web interface for requesting coins.

Network Details

Parameter	Value
Signet challenge	512102a3f8184701a033e5f8faa295647374b0bbc868082240d6e7ad8e9ecb0d86e6d451ae
Genesis hash	00000008819873e925422c1ff0f99f7cc9bbb232af63a077a480a3633bee1ef6
Block interval	~30 seconds
RPC port	38332
P2P port	38333
Known peer	15.235.3.238:38333

Running the Signet Node

docker-compose up -d

This builds and starts the Bitcoin Core signet node with the custom challenge, miner, and peer configuration. Chain data is persisted in the btc-data Docker volume.

To enable mining on the node, set MINERENABLED=1:

MINERENABLED=1 docker-compose up -d

Faucet

The faucet allows anyone to request test BTC on the Angor signet. It is fully self-bootstrapping -- on first startup it automatically creates the Bitcoin Core wallet, imports the faucet address, and rescans the blockchain. No operator intervention is required.

Faucet API

The API communicates directly with Bitcoin Core via JSON-RPC (no external indexer needed).

Endpoints:

Method	Path	Description
GET	/api/send/{address}/{amount?}	Send test BTC to an address (default 0.001 BTC)
POST	/api/send	Send test BTC via JSON body ({ "address": "...", "amount": 0.01 })
GET	/api/network/status	Network health: chain height, last block time, sync status

Running the Faucet API:

docker-compose -f faucet-api/docker-compose.yml up -d

The API starts on port 5500. It requires the signet node to be running and accessible on the btcnetwork Docker network.

For local development without Docker:

dotnet run --project faucet-api/faucet-api.csproj

Faucet Frontend

cd faucet
npm install
npm start

The dev server starts at http://localhost:4200 and proxies /api requests to the faucet API.

Configuration

The faucet API is configured via environment variables or faucet-api/appsettings.json:

Variable	Default	Description
Bitcoin__Mnemonic	(required)	BIP39 mnemonic for the faucet wallet
Bitcoin__Network	TestNet	Bitcoin network (TestNet for signet)
Bitcoin__FeeRate	10001	Fee rate in satoshis per kilobyte
Bitcoin__ChangeAddressIndex	0	BIP84 derivation index (m/84'/1'/0'/0/{index})
Bitcoin__RpcUrl	http://localhost:38332	Bitcoin Core RPC endpoint
Bitcoin__RpcUser	rpcuser	RPC username
Bitcoin__RpcPassword	rpcpassword	RPC password
Bitcoin__RpcWallet	custom_signet	Bitcoin Core wallet name