What Saibun does
Saibun helps you split one or more BSV UTXOs into many smaller UTXOs. It builds and signs the transaction in your browser, so your private key never leaves your device.
Client-side only
Signing happens locally. Online is only for fetching UTXOs or broadcasting.
Offline-capable
Paste raw transaction hex + output index (vout), sign offline, broadcast later.
About the name
Saibun (細分)
Japanese for "splitting into smaller parts" or "subdivision". The name reflects the tool's core purpose: breaking down larger UTXOs into many smaller, more manageable outputs.
Just as 細分 means precision division, Saibun helps you precisely control how your UTXOs are split.
Why split UTXOs?
Batch operations
Pre-split into many small UTXOs so future transactions can spend in parallel without reorganizing funds.
Protocol “dust”
Create many tiny UTXOs for token/protocol workflows that need lots of small spends.
Wallet hygiene
Organize funds into predictable chunks (for testing, spending policies, or operational separation).
How it works
Keys
Generate or import a WIF for signing.
UTXOs
Fetch online or paste raw tx hex offline.
Configure
Choose output count, satoshis, fee rate, recipient.
Build
Sign, download hex, and broadcast when ready.
Saibun uses standard P2PKH transactions and computes fees from an estimated byte size. Any remaining balance returns to a change output (your source address).
Glossary
FAQ
Ready to split UTXOs?
Start with a small test amount, review the transaction, then broadcast.
Want to learn Bitcoin Script?
The Script Guide covers 30 templates — hash puzzles, time locks, atomic swaps, and more — with opcode-by-opcode walkthroughs.