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Wrap & Unwrap BTC

frBTC is your Bitcoin made programmable: a token backed 1:1 by real BTC that works with on-chain apps and settles natively on Bitcoin. Wrapping is how you get frBTC; unwrapping turns it back into native BTC.

Minting frBTC (Wrapping BTC to frBTC)​

Minting frBTC locks your BTC and mints an equal amount of frBTC in the same step. It is a 1:1 conversion: 1 BTC mints you 1 frBTC, instantly.

In practice you rarely wrap by hand. When you swap starting from BTC, the app wraps to frBTC and performs the swap in a single, atomic transaction. The wrapping happens behind the scenes.

Redeeming BTC (Unwrapping frBTC to BTC)​

Unwrapping burns your frBTC and releases the underlying native BTC back to you. Unlike wrapping, unwrapping is authorized by the distributed group of signers that custodies the Bitcoin (no single party controls it). See What is SUBFROST for how that custody works.

Why there is a wait​

Your BTC arrives after 3 to 7 block confirmations. The exact number moves with fee-rate volatility, so treat it as a range rather than a fixed number.

The wait exists to protect the reserve from a Bitcoin reorg, and the reason is worth understanding, because it is the kind of thing that sounds like caution and is actually arithmetic:

Suppose there were no wait, and your frBTC became BTC the instant you unwrapped. Now Bitcoin reorgs away the last block. The signers already agreed to the unwrap and paid out, but the burn of your frBTC was undone by the reorg. You would end up holding both the frBTC and the BTC, and the reserve would be short.

Waiting a few blocks closes that window. A reorg deep enough to reach past 3 to 7 blocks is prohibitively expensive to pull off, so that depth is enough.

Fees​

Minting and redeeming each charge 0.1%, and the rate is the same in both directions. Wrap 1 BTC and you mint 0.999 frBTC; unwrap 1 frBTC and you redeem 0.999 BTC.

The fee is not fixed in the contract's code. It is an on-chain parameter that the protocol can change, so treat 0.1% as the rate in force today rather than a permanent guarantee. The app always quotes you the exact amount you will receive before you confirm.

Next steps​