Bitcoin on Sui: Getting Started with Hashi
Bitcoin is the largest pool of idle capital in crypto, and most of it never moves, because using it anywhere else has meant handing it to a custodian or a wrapped-token bridge. Hashi is Sui's answer. Your BTC stays on Bitcoin, held at an address controlled jointly by Hashi's validator committee, which signs with threshold MPC, and an independent guardian layer. Against it, hBTC is minted on Sui and works across Sui apps. Burn the hBTC and the BTC is released back on Bitcoin. Hashi is now live on Sui mainnet in a phased rollout, partners first, backed by more than $500 million in commitments from over 20 partners including Anchorage Digital. In early November about 9.6 hBTC had been minted onchain, and you can watch that number grow.
This session explains how Hashi works under the hood and gets you building with it. We read the live mainnet deployment directly: the Hashi object, the deposit and withdrawal queues, the committee and the hBTC supply. Then we use the Hashi TypeScript SDK on testnet with Bitcoin signet to run the full user journey: generate a personal Bitcoin deposit address for a Sui account, send signet BTC to it, follow the deposit through committee approval until hBTC is minted, and request a withdrawal back to Bitcoin. You build hBTC Desk, a small app that runs the testnet round trip and shows the live mainnet numbers beside it.
What You'll Learn
- How Hashi keeps BTC on Bitcoin: per-account deposit addresses, joint control by the validator committee and the guardian layer, threshold MPC signing, and how hBTC is minted and burned
- What is live today: reading the mainnet package, the deposit and withdrawal queues and the hBTC supply with GraphQL, and what a phased rollout means for builders
- The SDK: @mysten/hashi, generating a deposit address, submitting a deposit, tracking its status, and requesting or cancelling a withdrawal
- Building on hBTC: using it like any other Sui coin in your own Move code and programmable transactions, with 8 decimals and integer base units from end to end
- Honest limits: the SDK is pre-1.0 and not yet wired to mainnet, deposits wait for Bitcoin confirmations and a time delay, and how to show pending states so nobody pays twice
- How to ship hBTC Desk: deposit signet BTC, watch hBTC arrive on Sui testnet, withdraw back to a Bitcoin address, and compare it with the live mainnet numbers
Who Should Attend
- DeFi builders who want Bitcoin as collateral in lending, trading or vaults
- Wallet and payments teams that want to hold and move BTC inside Sui apps
- Developers who joined the bridging and CCTP sessions and want the Bitcoin side of the story
- Bitcoin holders curious how BTC can be used on another chain without giving up custody to a single company
What to Bring
- Laptop with Node.js 22+ and pnpm, and the latest @mysten/sui and @mysten/hashi
- A Sui testnet wallet
- A Bitcoin wallet that supports signet, such as Sparrow. We share a signet faucet in class
- Basic TypeScript. No Bitcoin scripting required
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