Zest V1 Review 2026: Bitcoin Lending on Stacks

Zest V1 is the version of Zest Protocol tracked as a lending market on Stacks. Zest describes itself as an open-source, on-chain lending platform built for Bitcoin, where users can earn on or borrow against their BTC. The tracker has listed it since April 2024.

At about $2.4M in TVL, V1 is small. The Zest homepage shows a much larger figure of roughly $80.9M across its Stacks suite, which covers lending, swaps and yield vaults. The two numbers measure different scopes, so they should not be read as the same product.

The team presents itself as Stacks core contributors and Bitcoin DeFi operators. It claims 2+ years of mainnet lending with zero bad debt and a peak TVL of $100M. These are the project's own claims. Its current messaging centres on Bitcoin Collateral Vaults, a newer design that is separate from V1.

Zest V1 is a pooled lending market. Lenders deposit assets into a shared pool and earn interest paid by borrowers. Borrowers lock collateral, such as sBTC, and draw loans against it up to a limit set by the protocol.

Rates float with supply and demand. When more of a pool is borrowed, rates generally rise. If a borrower's collateral value drops too far relative to the debt, the position can be liquidated so lenders are repaid.

All of this runs through smart contracts on Stacks, a Bitcoin layer. That means BTC exposure here is through Stacks assets such as sBTC. Zest's newer Bitcoin Collateral Vaults take a different route, keeping BTC in a Taproot vault on Bitcoin while the borrowing happens on another chain.

Zest V1's fee schedule is not published on the homepage. Users normally see the supply rate, borrow rate and any protocol reserve cut inside the app or the technical documentation, along with network transaction fees paid on Stacks.

The homepage shows example rates, such as a 0.98% supply rate on sBTC, 4.05% on STX and 3.41% on USDCx borrowing. These are snapshots that move with utilization. Check the live figures in the app before acting.

No audits are listed for Zest V1 in the tracking data, and the homepage does not name auditors. The code is described as open source, so it can be reviewed publicly, but that is not the same as an independent audit. Lending protocols carry smart-contract, oracle and liquidation risk, and funds can be lost if any of these fail.

The protocol is non-custodial in the usual DeFi sense: users interact with contracts from their own wallet. The team claims zero bad debt and no BTC lost over 2+ years of mainnet lending, which is self-reported. Zest does not state any regulatory licence on its homepage. Only deposit what you can afford to lose, and verify the official site and token contract before connecting a wallet.

Zest V1 is for crypto users who hold BTC-linked assets on Stacks and want to lend them or borrow against them. It suits people who accept DeFi smart-contract risk and can monitor a loan position. It is less suited to anyone who wants native BTC to stay on Bitcoin, which is what Zest's newer vault product targets.