Stacks (STX) is a Layer-1 blockchain that uses a "Proof of Transfer" (PoX) consensus mechanism anchored to Bitcoin, rather than a token issued on Ethereum, Solana, or another chain.
Miners spend already-mined BTC to win the right to produce Stacks blocks and are paid in STX, while Stacks blocks settle their state onto the Bitcoin chain. Since the Nakamoto upgrade, Stacks transactions inherit Bitcoin-level finality. The network also supports sBTC, a 1:1 Bitcoin-backed programmable asset live on mainnet since December 17, 2024.
Stacks differentiates itself by building smart-contract and DeFi functionality directly on top of Bitcoin's security rather than on a separate execution chain. This lets STX capture activity from Bitcoin-native lending, staking, and yield products.
The network has surpassed 1.6 million wallets, and Bitcoin Staking — a PoX upgrade letting participants lock BTC alongside STX for BTC-denominated yield without giving up custody — entered public testnet ahead of a planned Q3 2026 mainnet launch. Products such as Zest Protocol's Stacks Vaults and Stacking DAO's stBTC extend this Bitcoin-DeFi ecosystem.
STX is a utility token that functions as the native gas asset of the Stacks blockchain, used to pay transaction and smart-contract fees.
Holders can also participate in "Stacking," locking STX for fixed cycles to support consensus and security, in return earning a share of the Bitcoin that miners transfer as block rewards; this can be done directly, subject to a minimum STX threshold, or through delegation to a pool. STX holders additionally take part in on-chain governance by proposing and discussing Stacks Improvement Proposals (SIPs).
STX has no hard-capped maximum supply, with circulating supply currently around 1.86 billion STX. Roughly 1.8 billion STX is modeled to be in circulation by 2050, a charting reference rather than an actual cap.
Stacks, originally called Blockstack, began as a research project within Princeton University's computer science department in 2013 and later raised $5 million in venture capital. In 2017, it raised approximately $47 million in a token sale conducted under a Regulation D exemption to accredited investors.
In July 2019, the U.S. SEC qualified Blockstack PBC's Regulation A+ token offering, authorized for up to $50 million; the round actually raised $23 million after about ten months of offering activity.
Stacks is its own Layer-1 blockchain that uses a "Proof of Transfer" (PoX) consensus mechanism anchored to Bitcoin, rather than running as a token on Ethereum or Solana.
Miners spend already-mined Bitcoin to win the right to produce Stacks blocks, and Stacks blocks settle their state onto the Bitcoin chain. Since the Nakamoto upgrade, Stacks transactions inherit Bitcoin-level finality, tying Stacks' security directly to Bitcoin's proof-of-work network rather than to an independent validator or staking set.
Stacks was co-founded in 2013 by Muneeb Ali and Ryan Shea within Princeton University's computer science department, under the original name Blockstack.
As of 2026, Muneeb Ali serves as CEO of Trust Machines, a company building Bitcoin Layer-2 application infrastructure, and also holds a board seat at Hiro Systems. Ryan Shea has since moved into angel investing and co-founded a separate venture, Opus Wallet, and no longer holds an operational leadership role at Stacks.
No single company issues or controls Stacks today; development and governance support are split across several organizations.
The original issuer, Blockstack PBC, became the first company to have the SEC qualify a Regulation A+ token offering, in July 2019.
Stacks is governed through a public Stacks Improvement Proposal (SIP) process that anyone in the community can submit, covering protocol design, implementation, and governance changes. The process itself is defined by SIP-000, and proposals are tracked in a public GitHub repository.
STX holders also participate directly in network security through "Stacking," locking tokens for fixed cycles to earn a share of transferred Bitcoin. Two recent proposals, SIP-044 and SIP-045, formalized a "Bitcoin Staking" upgrade to PoX, letting participants lock BTC on the Bitcoin chain itself alongside STX to earn BTC yield without giving up custody.
Bitcoin Staking, a PoX upgrade formalized under SIP-044 and SIP-045, entered public testnet in mid-2026 ahead of a planned Q3 2026 mainnet launch. It will let participants lock BTC alongside STX to earn BTC-denominated yield.
Stacks has been audited by multiple independent security firms, covering both its core blockchain and its sBTC Bitcoin-bridge system. Trail of Bits and NCC Group audited the core blockchain and wallet, while CoinFabrik, Ottersec, and Clarity Alliance separately audited the sBTC bridge system.
Immunefi has also hosted two community "Attackathon" security reviews. Stacks states that all high- or critical-severity issues identified in audits have been mitigated or made obsolete, a self-reported claim. One secondary market-data aggregator estimates the top 25 STX wallets hold roughly half of circulating supply, an unverified concentration figure.