Learn more about the Stacks blockchain


The Stacks 2.0 blockchain connects to Bitcoin for security and enables decentralized apps and predictable smart contracts. Stacks 2.0 implements a new mining mechanism called Proof of Transfer (PoX). PoX anchors to Bitcoin security and makes it possible to reward holders of Stacks (STX) tokens, the native token of the Stacks 2.0 blockchain, with bitcoins.


The Stacks 2.0 blockchain is in active development. While the final release ("mainnet") is in the works, you can already get familiar with Stacks 2.0 capabilities on the "testnet".

For more information on the testnet, have a look at this page:

Graphic for: Testnet
Learn about testnet phases, timelines, and features


You can view accounts, blocks, transactions, and smart contracts broadcasted to the Stacks 2.0 blockchain using the Stacks 2.0 Explorer.


Managing accountsLearn how to generate and review accounts
Managing accounts
Sending tokensLearn how to transfer tokens
Sending tokens
Running a testnet nodeLearn how to set up and run a testnet node.
Running a testnet node


Clarity Smart Contracts

A Smart Contract is code running on the Stacks Blockchain that executes autonomously.

Smart contracts on the Stacks 2.0 blockchain are written in a new language called Clarity. This language gives developers a safe way to build complex smart contracts. It's main features are:

  • Predictability: The Clarity language uses precise and unambiguous syntax that allows developers to predict exactly how their contracts will be executed
  • Security: The Clarity language allows users to supply their own conditions for transactions that ensure that a contract may never unexpectedly transfer a token owned by a user
  • No compiling: Contracts written in Clarity are broadcasted on the blockchain exactly as they are written by developers. This ensures that the code developers wrote, analyzed, and tested, is exactly what gets executed
Graphic for: Write smart contracts
Write smart contracts
Overview and guides for getting started with Clarity

Stacks Mining

Mining is required to make the network trustworthy and secure, by verifying transaction information. Mining is the act of participation in the consensus mechanism of the Stacks 2.0 blockchain, called Proof of Transfer (PoX). To incentivize miners, who have to run mining software on their machine, they receive freshly minted Stacks (STX) tokens.

Graphic for: Mine Stacks tokens
Mine Stacks tokens
Set up and run a miner on the Stacks 2.0 testnet

Proof of Transfer (PoX)

Proof of Transfer (PoX) is the consensus mechanism that leverages the security and stability of Bitcoin to create new blockchains, without modifying the Bitcoin protocol.

PoX makes it possible to reward holders of Stacks Token (STX) with Bitcoin: instead of spending energy, Stacks miners transfer Bitcoin to holders of Stacks Token (STX) to mine blocks. An implementation of this is called Stacking.


Stackers are Stacks (STX) Token holders who help secure the network by effectively acting as validators on the network, incentivizing honest behavior on the part of miners. Stackers have to lock up Stacks (STX) for a certain period of time. As a reward, Stackers receive the Bitcoin that miners transfer as part of Proof of Transfer (PoX).

Protocol specification

The Stacks 2.0 blockchain specification consists a set of proposals, called Stacks improvement proposals (SIPs). Each SIP is aimed at describing the implementation of a part of the Stacks 2.0 blockchain. Together, all proposals contain concise technical specifications of features or standards and the rationale behind it.

You can review the SIP folder to find all proposals. Reading through the SIPs will help understand the Stacks 2.0 details on a propotcol level.