Our work
We made USDC available on Bitcoin.
The Runes bridge connects Starknet and Bitcoin, so Bitcoin users can hold assets like USDC directly on the Bitcoin network. We built it for Starknet, with Xverse.
- Client
- Starkware
- Protocol
- Runes on Bitcoin
- Date
- May 2025
Overview
What is the Runes bridge?
USDC was not available on Bitcoin. A Bitcoin user who wanted it had to leave the network.
The bridge solves this with Runes, a protocol for creating and moving tokens on Bitcoin. Starknet launched Asset Runes on it in May 2025, starting with USDC. They live on Bitcoin and can be redeemed 1:1 on Starknet, which announced them as fully reserved.
Why it matters
Why it was useful
Bitcoin users got a dollar asset on the network they already use. At launch they could trade it and provide liquidity on DotSwap.
The bridge also goes the other way. At launch, the top five Bitcoin Runes could move to Starknet and trade there.
Security
Who secures the bridge
A federation of Bitcoin actors secures the bridge through a multisig, and Xverse is one of the signers. These co-signers, not smart contracts, enforce the rules.
So users trust the group. Xverse says this model relies on the signers' honesty, and that activating OP_CAT, a Bitcoin script operation, would remove the need for them.
The hard parts of the project were the complexity of Bitcoin and the Runes protocol, and building a strong security model in step with those signers.
Contact our team
We take 4 protocols per quarter. Formal verification demands deep focus. We'd rather verify fewer contracts well than many poorly.
Continue reading
Learn more
Starknet's announcement of Asset Runes.
Bitcoin Use Cases on Starknet Are Getting Real, Starknet's recap of the launch.
How to swap tokens from Bitcoin to Starknet, the Xverse guide.