Polkadot is a blockchain network built so that many separate blockchains can share one set of validators and send messages to each other. It was conceived by Gavin Wood, a co-founder of Ethereum and the author of Ethereum's technical specification. He published the Polkadot whitepaper in 2016, and the network's first block was produced in May 2020. The native token is DOT. The official Polkadot website is the starting point for the project.
Who Builds and Governs It
Three groups are often confused. Parity Technologies is the software company that wrote much of the core code. The Web3 Foundation is a Swiss foundation that funds research and development. Neither one governs the network. Protocol changes are decided by DOT holders through on-chain voting, under a system called OpenGov that went live in 2023. Approved upgrades are applied by the chain itself, without a hard fork.
The Layer-0 Idea
Most blockchains run alone. Each has its own validators and its own security, and none can natively read another chain's state. Polkadot sits underneath a group of chains and provides consensus and security for all of them. This is why it is often called a layer-0 network.
The pitch to developers is that they can build a chain tailored to one purpose without having to recruit and pay for their own validator set.
How Polkadot Works
- Relay Chain: the central chain. It runs consensus, handles staking and finalizes blocks for every connected chain. It was deliberately kept simple and does not host general smart contracts.
- Parachains: independent blockchains connected to the Relay Chain. Each has its own logic and often its own token. Their blocks are checked and finalized by Relay Chain validators.
- Collators: nodes that gather transactions on a parachain and produce candidate blocks for validators to verify.
- Bridges: connections to outside networks such as Ethereum, which are not part of the shared security set.
Parachains talk to each other using XCM, a cross-chain message format. XCM lets one chain instruct another to move tokens or call a function, which is how assets travel between parachains without a third-party bridge. The Polkadot developer documentation covers the architecture in depth.
Shared Security
A new blockchain normally has to attract its own validators. In the early days that set is small, which makes the chain cheap to attack. A Polkadot parachain does not have this problem. Its state transitions are verified by the Relay Chain validator set, which is backed by all staked DOT. A parachain with a small community gets the same security guarantees as a large one.
The cost is dependence. A parachain relies on the Relay Chain to keep running and has to pay for access to it.
From Slot Auctions to Coretime
For the first few years, access was sold through parachain slot auctions, which began on Polkadot in late 2021. Teams bid DOT for a lease lasting up to about two years. The winning DOT was locked for the lease and then returned. Many teams raised their bids through crowdloans, where supporters lent their DOT in exchange for the project's tokens.
That model made entry expensive and rigid. In 2024, Polkadot replaced it with Agile Coretime. A chain or application now buys processing time on the network, either in bulk for a fixed period or on demand. This change was a central part of the upgrade program known as Polkadot 2.0, and auctions are no longer how new projects join.
What DOT Does
- Staking: validators and nominators stake DOT to secure the network. Nominators back validators they trust and share in both rewards and penalties.
- Governance: DOT holders vote on referenda that cover upgrades, parameters and treasury spending.
- Coretime: DOT is used to buy the block production time that chains need.
- Fees: DOT pays transaction fees on Polkadot's system chains.
Polkadot uses Nominated Proof of Stake. Staked DOT is subject to slashing if the validator you nominate misbehaves, and unstaking has involved a waiting period that has historically been 28 days.
For most of its history DOT had no supply cap, and new tokens were issued each year to pay stakers and fund the treasury. In 2025, token holders voted to introduce a maximum supply of 2.1 billion DOT, with issuance stepping down over time. Check the official documentation for the current schedule before relying on any figure.
Kusama
Kusama is Polkadot's sister network, launched in 2019. It runs very similar code with faster governance and lower economic stakes. New features and parachains often go live on Kusama first. It has its own token, KSM, and it is a real network with real value, not a testnet.
Risks to Understand
- Competition: Ethereum Layer 2 networks, Cosmos and other ecosystems also offer ways to launch application-specific chains.
- Complexity: the Relay Chain, parachains, coretime and XCM are harder to understand than a single-chain design, for users and developers alike.
- Fragmentation: tokens and liquidity are spread across many parachains.
- Slashing: nominators can lose part of their stake for a validator's faults.
- Dilution: holders who do not stake see their share of supply shrink as new DOT is issued.
A common mistake is choosing validators only by the highest advertised return. Commission, uptime and the risk of being slashed matter as much.
Nothing in this article is financial advice.
Key Polkadot Facts
- Whitepaper: 2016, by Gavin Wood
- Network launch: May 2020
- Consensus: Nominated Proof of Stake
- Governance: on-chain voting by DOT holders (OpenGov)
- Access model: Agile Coretime, which replaced slot auctions in 2024
- Sister network: Kusama (KSM)
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