Bitcoin Test Networks

Never test with real bitcoins. Bitcoin provides multiple test networks for development and experimentation.

Network Comparison

Network	Coins	Block Time	Stability	Use Case
Mainnet	Real BTC	~10 min	Stable	Production
Testnet3	Free tBTC	~10 min	Variable	Integration testing
Signet	Free sBTC	~10 min	Stable	Reliable testing
Regtest	Generated	Instant	Local	Unit testing

Testnet3

The primary public test network since 2012.

Characteristics

Address prefix: m or n (P2PKH), 2 (P2SH), tb1 (Bech32)
Genesis block: Different from mainnet
Difficulty: Resets if no block for 20 minutes
Coins: Free from faucets

API Access

# mempool.space testnet
curl https://mempool.space/testnet/api/blocks/tip/height

# Address info
curl https://mempool.space/testnet/api/address/{address}

Faucets

Faucet	URL
coinfaucet.eu	https://coinfaucet.eu/en/btc-testnet/
mempool.co	https://testnet-faucet.mempool.co/
bitcoinfaucet	https://bitcoinfaucet.uo1.net/

Limitations

Unstable difficulty: Long block times during low activity
Spam: Sometimes flooded with test transactions
Reorgs: More common than mainnet

Signet

A more reliable test network with signed blocks (BIP-325).

Characteristics

Address prefix: Same as testnet (tb1)
Block signing: Centralized signers (default: Bitcoin Core devs)
Predictable blocks: ~10 minutes, no difficulty resets
Coins: Free from faucets

Why Use Signet?

Testnet	Signet
Unpredictable blocks	Consistent 10-min blocks
Difficulty resets	Stable difficulty
Anyone can mine	Signed by authorities
More reorgs	Fewer reorgs

API Access

# mempool.space signet
curl https://mempool.space/signet/api/blocks/tip/height

Faucet

Configuration

# bitcoin.conf
signet=1
[signet]
signetchallenge=... # Default uses Bitcoin Core signet

Regtest (Regression Test)

Local, private test network for development.

Characteristics

No network: Runs locally only
Instant blocks: Generate on demand
Full control: You create all blocks and transactions
Perfect for: Unit tests, CI/CD

Setup

# Start regtest node
bitcoind -regtest -daemon

# Create wallet
bitcoin-cli -regtest createwallet "test"

# Generate address
bitcoin-cli -regtest getnewaddress

# Mine 101 blocks (100 for maturity + 1)
bitcoin-cli -regtest generatetoaddress 101 <address>

# Check balance
bitcoin-cli -regtest getbalance

Instant Transactions

# Send transaction
bitcoin-cli -regtest sendtoaddress <address> 1.0

# Mine block to confirm
bitcoin-cli -regtest generatetoaddress 1 <mining_address>

Network-Specific Settings

Address Prefixes

Type	Mainnet	Testnet/Signet
P2PKH	`1`	`m` or `n`
P2SH	`3`	`2`
Bech32	`bc1`	`tb1`

Version Bytes

Key Type	Mainnet	Testnet
WIF	0x80	0xef
xpub	0x0488B21E	0x043587CF
xprv	0x0488ADE4	0x04358394

Agent Development Workflow

1. Unit Tests (Regtest)

# Fast, isolated tests
def test_transaction_creation():
    # Generate blocks for funds
    rpc.generatetoaddress(101, address)

    # Create and broadcast transaction
    txid = rpc.sendtoaddress(recipient, 0.1)

    # Mine to confirm
    rpc.generatetoaddress(1, address)

    # Verify
    tx = rpc.gettransaction(txid)
    assert tx['confirmations'] == 1

2. Integration Tests (Signet)

# Realistic testing with stable network
def test_payment_flow():
    # Get signet coins from faucet first

    # Test with real network conditions
    txid = broadcast_transaction(signed_tx)

    # Wait for confirmation (~10 min)
    wait_for_confirmations(txid, 1)

3. Staging (Testnet)

# Full integration before mainnet
def test_production_flow():
    # Test against testnet services
    # Verify third-party integrations
    # Load testing

Best Practices

Do

✅ Always start development on regtest
✅ Use signet for realistic testing
✅ Test edge cases (reorgs, failures)
✅ Keep testnet/mainnet code paths separate
✅ Return testnet coins to faucets when done

Don’t

❌ Never test with real BTC
❌ Don’t assume testnet stability
❌ Don’t hardcode network parameters
❌ Don’t rely on testnet for production checks

Configuration Examples

JavaScript (bitcoinjs-lib)

const bitcoin = require('bitcoinjs-lib');

// Mainnet (default)
const mainnet = bitcoin.networks.bitcoin;

// Testnet
const testnet = bitcoin.networks.testnet;

// Regtest
const regtest = bitcoin.networks.regtest;

// Use network
const address = bitcoin.payments.p2wpkh({
  pubkey: publicKey,
  network: testnet
}).address;

Python (python-bitcoinlib)

from bitcoin import SelectParams

# Select network
SelectParams('testnet')  # or 'mainnet', 'regtest'

Machine-Readable Summary

{
  "topic": "bitcoin-test-networks",
  "networks": {
    "testnet": {
      "prefix_bech32": "tb",
      "api": "https://mempool.space/testnet/api"
    },
    "signet": {
      "prefix_bech32": "tb",
      "api": "https://mempool.space/signet/api"
    },
    "regtest": {
      "prefix_bech32": "bcrt",
      "local_only": true
    }
  },
  "faucets": {
    "testnet": ["https://coinfaucet.eu/en/btc-testnet/"],
    "signet": ["https://signetfaucet.com/"]
  }
}