Stacks stx

Stacks (formerly associated with the Blockstack name) is a Bitcoin layer-2 blockchain for smart contracts and decentralized applications. The current Stacks site describes it as a Bitcoin L2 that lets users and builders use Bitcoin as a secure base layer, while the official documentation calls it a fast, low-cost, builder-friendly layer 2 on Bitcoin. Its native asset is STX, used for transaction fees, smart-contract execution, and participation in the network's incentive mechanisms.

Stacks keeps its own state and blocks rather than changing Bitcoin's protocol. It is linked to Bitcoin through Proof of Transfer (PoX), a consensus design that records Stacks activity and chain history against Bitcoin. This gives Stacks applications access to Bitcoin's settlement and security properties while retaining a programmable execution environment.

The ecosystem targets Bitcoin-native applications, including decentralized finance, NFTs, naming, and Bitcoin-backed assets such as sBTC. Clarity is Stacks' smart-contract language: contracts are published in readable source form and are designed to be predictable and decidable, reducing classes of bugs associated with opaque compilation and unrestricted execution.

Bitcoin prioritizes a conservative, limited scripting model, which contributes to its security but restricts complex application logic. As a result, developers seeking lending, exchanges, NFTs, naming, and other programmable applications have often had to use separate chains or custodial and wrapped-asset approaches. Those approaches can fragment liquidity and introduce additional trust, bridge, or custody assumptions.

Stacks addresses this gap by placing a programmable layer alongside Bitcoin rather than modifying Bitcoin itself. PoX links the two chains, while Clarity contracts can read relevant Bitcoin state and settle Stacks transactions back to Bitcoin. This is intended to make Bitcoin capital more productive without giving up Bitcoin as the settlement anchor, although users still face ordinary smart-contract, protocol, market, and operational risks and should not interpret Bitcoin anchoring as a guarantee of application safety or token value.

Stacks uses Proof of Transfer (PoX) as its Bitcoin-linked consensus mechanism. Miners compete to produce Stacks blocks by transferring Bitcoin to designated participants rather than destroying it. Those participants, called Stackers, lock or signal STX for a protocol-defined period and receive BTC rewards from the committed Bitcoin. The mechanism creates an economic relationship between Stacks block production and Bitcoin without requiring a Bitcoin network upgrade.

A Stacks block is anchored to a Bitcoin block, and Stacks transactions ultimately settle through this linkage. The Stacks core reference implementation describes leader election as occurring on the Bitcoin blockchain while STX miners write blocks on the separate Stacks blockchain. The resulting architecture combines Bitcoin anchoring with a dedicated execution chain for contracts and applications.

Applications are written in Clarity. Clarity is intentionally decidable and does not use a conventional compiler/bytecode pipeline: the code broadcast to the chain is the code users can inspect. Contracts can observe Bitcoin state, and post-conditions allow users or wallets to require that asset-transfer conditions hold or the transaction aborts. Stacks also uses microblocks to process state transitions and contract interactions between Bitcoin-anchored blocks, improving responsiveness while preserving anchor-based settlement.

STX is the fuel for Stacks transactions and contracts and also supports open participation in mining and stacking. The broader ecosystem includes Bitcoin DeFi, NFTs, BNS names, and sBTC, a 1:1 Bitcoin-backed asset designed to enable movement of BTC into and out of Bitcoin layers. Specific reward rates, protocol parameters, and sBTC operational assumptions can change with network upgrades, so users should consult current documentation before transacting.