Polkadot is a decentralized, nominated proof-of-stake blockchain with smart contract functionality. The cryptocurrency native to the blockchain is the DOT.

Designed to facilitate interoperability, Polkadot enables independent blockchains to exchange data and assets securely without relying on centralized intermediaries. This cross-chain communication framework allows for the development of decentralized applications (dApps) and services that span multiple blockchains within a unified network architecture.

Polkadot was created by the Ethereum co-founder Gavin Wood, Robert Habermeier and Peter Czaban. The white paper for Polkadot was published by Wood in 2016. The Polkadot SDK and other core technology components are being developed by Parity Technologies. The project raised over $144.3 million in its Initial coin offering in October 2017.

In 2017, Gavin Wood, Aeron Buchanan, Peter Czaban, Reto Trinkler, and Mathias Bucher, established the Web3 Foundation, a non-profit organization based in Zug, Switzerland, to promote and provide funding for blockchain-based decentralized web technologies. The Polkadot SDK and other core technology components are being developed by Parity Technologies, a blockchain infrastructure company founded in 2015 by Gavin Wood and Jutta Steiner.

In October 2017, Polkadot raised over $144.3 million in its initial coin offering (ICO). Shortly after the ICO, a vulnerability in the multi-signature wallets developed by Parity Technologies led to the freezing of approximately $150 million worth of Ethereum, including a significant portion of the funds raised. Over 500 wallets were impacted, including Polkadot’s wallet, which held a significant portion of the $144.3 million raised during its ICO. In 2019, Polkadot raised an additional $43 million through a private token sale.

In May 2020, Polkadot launched its mainnet under a proof-of-authority consensus model, managed by the Web3 Foundation during its early phase. By June 2020, the network transitioned to a Nominated Proof-of-Stake (NPoS) consensus mechanism, allowing token holders to nominate validators to secure the network and process transactions.

In December 2021, Polkadot introduced parachain functionality, allowing multiple blockchains to run simultaneously and connect to the network's Relay Chain.

In December 2024, Polkadot's canary network Kusama underwent a stress test known as "The Spammening," handling approximately 143,000 transactions per second (TPS) at just 23% capacity.

Polkadot is founded on the premise that there will be a multitude of blockchains in the future. It provides an open-source software development kit called Polkadot SDK that can be used by development teams to build their own blockchains. These blockchains can function independently, known as "solochains," or integrate into the Polkadot network as "parachains," thereby benefiting from shared security and cross-chain communication capabilities.

Polkadot offers three properties to parachains: sovereignty, shared security and interoperability.