Bitcoin SPV inside a Soroban contract, in one picture.
The contract does not call a Bitcoin node.
The caller brings 6 headers, a Merkle proof, and the raw transaction.
The contract checks the math.
Babylon, Templar, and others are in this design space too.
We are not claiming the only honest design. We are claiming this one: script on Bitcoin, verifier on Soroban, USDC on Stellar.
Wrapped BTC is an IOU.
A good IOU is still an IOU. An issuer holds BTC and mints a token on another chain.
Writz is a script on Bitcoin and a verifier on Soroban. The collateral never becomes a token named BTC.
Phase 1 still has a protocol key. That is a real limitation.
The direction is less protocol key, not more. We write about that when there is code, not a promise.
How the BTC gets locked.
A P2WSH output on Bitcoin. Two paths out. Only two.
Path A: you and the protocol sign.
Path B: the timelock expires, you sign alone.
The relayer is public on testnet: https://t.co/IttLJ1Br0s
Give it a txid. It returns the headers and the proof shaped for the call.
Docs: https://t.co/MExMCNjQrm
Bitcoin SPV inside a Soroban contract, in one picture.
The contract does not call a Bitcoin node.
The caller brings 6 headers, a Merkle proof, and the raw transaction.
The contract checks the math.
Your Bitcoin never leaves Bitcoin. Your loan, nobody sees.
Real BTC collateral, verified on-chain via SPV. Zero custodians. ZK-private positions.
Your keys. Your coins. Your loans.
Proof of win 🥇
Had the privilege of pitching @WritzProtocol in Bogotá at Pulso Hackathon Colombia 🇨🇴 and we won 1st place!
This unlocked:
✈️ A trip to São Paulo for the Stellar Builder Summit
💰 Funding through Instawards program to keep building
Proud of this team ⚡️
We will post here the way we build: in public, technically, without a launch every week.
If you hold BTC and have never used it as collateral without handing it to someone, this is for you.
Questions in the replies. We read them.
Writz Protocol lets you lock real BTC from a Bitcoin wallet and borrow USDC on Stellar.
No bridge.
No custodian.
No wrapped token.
A short thread on what that means, what we have already shipped, and where to read the code.
What you can open today:
Site and testnet app: https://t.co/8vYAKfdUyS
Docs: https://t.co/MExMCNjQrm
Code (Apache-2.0): https://t.co/b6g6yFsOKt
Testnet. Not mainnet. We will say mainnet when mainnet is true.
This is where it started
5 July 2026. One video. No protocol account. The first time Writz existed on X.
Everything since then has been making that post true.
Writz Protocol ₿ 💰
BTCFi on Stellar 🔥
Lock real BTC directly from your Bitcoin wallet, borrow USDC on Stellar, and keep every position private - always.
- No bridge.
- No custodian.
- No wrapped tokens.
- No public balance sheet.