Transaction Builder
Build Bitcoin transactions with full control over inputs, outputs, scripts, and fees. Choose a template or craft your own.
Build from Address
Enter your Bitcoin address to load real UTXOs and craft a transaction.
Enter a mainnet or testnet address, then press Enter or click the refresh button.
How it works
Your wallet holds coins, not a balance
Bitcoin doesn't track a single 'balance' like a bank account. Your wallet actually holds individual digital coins called UTXOs, just like having specific ₹500, ₹200, and ₹100 bills in a physical leather wallet.
You can't split a coin, you spend it whole
Want to pay ₹300? You hand over your ₹500 bill and get ₹200 back as 'change.' Bitcoin works exactly the same: you must put the whole coin into the transaction, sending the leftover back to yourself.
The miner's fee depends on transaction size
Every transaction requires a fee to get confirmed by miners. But the fee isn't based on how much money you send, it's based on data size (vBytes). More input coins equal a physically larger transaction, requiring a higher fee.
Tiny amounts become 'dust', unusable forever
If your change output is too small, it will cost more in miner fees to spend than it's actually worth. These tiny 'dust' amounts get permanently stuck in your wallet. Smart wallets avoid creating them.
Smith handles the complexity automatically
Smith handles all of this automatically. Choose a template to see how different transaction types work, or build your own with full control over inputs, outputs, scripts, and fees.
Ready to build better transactions?
Choose a template to learn how different transaction types work, or build your own with full control.