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Learn what's possible with the Stacks layer for Bitcoin

What Stacks unlocks


NFTs on Bitcoin

Non-fungible tokens (NFTs) are a type of token that are not interchangeable. NFTs have unique traits that restrict the abillity to replace them with identical tokens. An NFT is a token that is unique, such as a piece of art, or ownership rights to a real-world asset such as a house.

Bringing NFTs to Bitcoin

As with fungible tokens, NFTs on the Stacks blockchain are created with Clarity smart contracts. Because of the relationship between Stacks and Bitcoin, NFTs created on Stacks settle to and are secured by Bitcoin. Marketplaces are enabling Lightning and Bitcoin payments and bitcoin yield-generating NFTs powered by Stacking are rounding out exciting new possibilities.

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DeFi on Bitcoin

Bitcoin DeFi is a large, untapped market given Bitcoin’s nearly $1 trillion market cap and increasing institutional adoption. However, despite the increasing use of Bitcoin as sovereign money, Bitcoin hasn’t been as productive an asset as other cryptocurrencies for DeFi without going through either centralized exchanges or separate blockchains in the form of wrapped BTC. Stacks changes this.

Stacks is uniquely positioned to enable true Bitcoin DeFi, given Stacks contracts' visibility into the Bitcoin state as well as Stacks’ inherent ability to leverage Bitcoin’s security and settlement assurances. The Stacks chain is tethered to Bitcoin through its Proof of Transfer  consensus mechanism, so all Stacks transactions settle on Bitcoin. This ensures that Stacks shares Bitcoin’s long-term, unparalleled security for transaction reorgs.



Blockchain Naming System (BNS) is a network system that binds Stacks usernames to off-chain state without relying on any central points of control.

Unlike DNS, anyone can create a namespace and set its properties. Namespaces are created on a first-come first-serve basis, and once created, they last forever.

BNS names have the following three key properties, making them a powerful tool for building all kinds of network applications.

BNS names properties

Globally unique. The protocol does not allow name collisions.

Human-meaningful. Each name is chosen by its creator.

Strongly owned. Only the name's owner can change the state it resolves to.

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BNS Docs
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How Stacks works


Proof of Transfer

Proof of Transfer (PoX) is a novel blockchain consensus mechanism that allows Stacks to settle transactions to Bitcoin. This unique relationship allows builders to leverage and extend Bitcoin’s powers without modifying Bitcoin itself.

Because all Stacks transactions settle on Bitcoin they benefit from Bitcoin’s security. PoX also has a sustainability benefit, as electricity already spent to secure Bitcoin is reused by Stacks, allowing builders to create more value from energy already spent.

Proof of Transfer whitepaper
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Why Bitcoin?
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Mining and Stacking

PoX is an extension to Proof-of-burn models where miners compete by ‘burning’ (destroying) a proof-of-work cryptocurrency from an established blockchain as a proxy for computing resources. Unlike proof-of-burn, however, rather than burning the cryptocurrency, miners transfer the committed cryptocurrency to other participants in the network who are 'Stacking'.

The Bitcoin transferred by miners is then used to provide Stacking rewards, paid in BTC to token holders for helping to ensure a stable network. Stacker do this by locking up their tokens for a certain time and signaling the canonical chain tip.

Together mining and Stacking secure the network and provide a myriad benefits for Stacks builders.

Benefits of PoX

Stacks and its apps inherit Bitcoin’s security via settlement

Apps built on Stacks can interact with Bitcoin on-chain data and state

Anyone can mine, no special hardware required

PoX allows developers to benefit from Bitcoin’s properties without modifying Bitcoin itself.

PoX reuses the energy already expended in Bitcoin's PoW

Allows to network participants to earn a bitcoin yield for helping secure the network

Provides new business model opportunities and funding models to builders

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Clarity is a safe and predictable language for smart contracts and an upgrade to existing smart contract languages that are rife with features that cause more harm than good. Bugs or malice in smart contracts cause large-scale irreversible harm. Clarity reduces the surface area for these bugs, makes it hard to write dangerous code, and makes it easy to see what the code will do before running it.

A leap forward in user protection

On other networks, users essentially have no choice but to trust developers that smart contract code is free from bugs or malice. With Clarity, smart contract code is available directly on-chain for all to see.

In addition, developers and users alike can see exactly what a Clarity contract will do before running it, eliminating not just surprises, but whole classes of common smart contract bugs as well.

Further, post-conditions enable the user or their wallets to set conditions that must be true when the contract finishes running. If these conditions are not met, because the contract tries to transfer more tokens for example, the transaction will abort.

Benefits of Clarity


Clarity uses precise syntax so developers know exactly how contracts will execute; with no compiler, no assemly, and no bytecode, contracts are broadcasted on the blockchain exactly as written. What you see is what you get.


Clarity is decidable rather than Turing complete; the minor loss of expressiveness is outweighed by the benefits in safety.


Allows users to supply their own conditions for transactions, ensuring a contract will never unexpectedly erroneously transfer any tokens.

Visibility into Bitcoin

Clarity smart contracts have visibility into Bitcoin state and can include Bitcoin-based logic.

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Smart contract docs
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Because each Stacks block is anchored to a Bitcoin block through the Proof of Transfer consensus mechanism, Stacks is necessarily limited to the same block times as the Bitcoin network. Microblocks allow the Stacks blockchain to perform state transitions between anchor blocks.

Microblocks are a powerful mechanism for developers to create performant, high quality applications on Stacks, while still inheriting the security of Bitcoin.

Benefits of Microblocks

Thousands of STX transactions in a single hash on Bitcoin

Speed. Stacks microblocks deliver nearly instant contract interactions

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STX Token

Stacks token (STX) allows for cheaper, more efficient app infrastructure connected to Bitcoin. Stacks also play a key role in incentivizing open mining, which is required on an open network; alternatives would be federated of closed networks.

Stacks are now being used to mine Stacks-based PoX tokens, allowing builders to incentivize early supports with a Stacking yield, which can further be used to generate a regular BTC Stacking yield.

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Expand your knowledge

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Frequently Asked Questions
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