Polkadot (DOT)

What Polkadot is

Polkadot is a network that rents secure blockspace to other blockchains. DOT is its native asset, and the Polkadot Wiki gives it three jobs: governance, staking and network access. Holders "can vote network governance and propose changes to the protocol, including fees, token inflation, and code upgrades"; they "can lock their tokens to secure the network and get staking rewards"; and DOT buys Coretime, the computation and interoperability capacity that chains built on Polkadot consume (source: Polkadot Wiki, learn-dot, read September 2026).

The chains that plug into Polkadot are called parachains, and the wiki now also describes them as rollups. They do not run their own validator set. They inherit Polkadot's, which is what "shared security" means in this context.

For where to buy Polkadot from your country or state, see the availability tables on this page and the venues at Exchanges.

How it works

The relay chain is the coordinating layer, and it does deliberately little. The wiki states that "the relay chain has deliberately minimal functionality — its primary purpose is to facilitate block production, core scheduling, data availability, and provide shared security to the rest of the network." It goes further: "the relay chain does not support user-facing functionalities — accounts, balance transfers, staking, and more have been migrated to Asset Hub, a system parachain."

That migration matters for anyone reading older material about Polkadot. Balance transfers and staking now happen on Asset Hub, not on the relay chain itself. The relay chain schedules work and guarantees that the work was done correctly.

Capacity is sold as cores, which the wiki compares to processor cores. A chain gets access to a core in one of two ways: as a dedicated parachain holding a core over a period, or as an on-demand parachain sharing cores with others. Both routes are paid for in DOT through the agile Coretime mechanism. This is the substantive difference from the earlier parachain auction model, in which a chain had to win a slot by locking a large amount of DOT for a fixed term. Coretime turns blockspace into something a project can buy in the amount it needs.

Three roles keep the system running. Validators produce relay chain blocks and verify the validity proofs that parachains submit. Nominators bond DOT behind validators to help them into the active set and share in the rewards. Collators are full nodes of both a parachain and the relay chain; they collect that parachain's transactions and generate the state transition proofs validators check.

Polkadot's consensus is nominated proof of stake. The wiki describes the mechanism plainly: "any potential validators can indicate their intention to be a validator candidate. Their candidacies are made public to all nominators, and a nominator, in turn, submits a capped list of candidates that it supports." Time is divided into eras, defined as "a period of 24 hours (6 hours on Kusama) during which an active set of validators is producing blocks."

Two details of the reward design are worth knowing before you stake. First, "the staking system pays out rewards equally to all validators regardless of stake," and nominators receive their share pro rata after the validator's commission. Backing an already-enormous validator therefore dilutes your share of a fixed per-validator payout. Second, slashing is joint: "if there is an attack in the case of NPoS, both the validator(s) and nominators will be slashed resulting in their stake being partly or fully confiscated by the network and then deposited to the treasury." Choosing a validator is a real decision, not a formality.

Supply and tokenomics

Polkadot changed its issuance model in November 2024. The old design targeted a percentage inflation rate, which compounds. The new one fixes the number of tokens issued each year, which does not.

A fixed number of new tokens against a growing base produces linear supply growth and a declining percentage inflation rate, which is exactly what the wiki says the change was for: it "shifted from a constant percentage model to one generating linear supply growth with decreasing inflation rates."

Gross issuance is not the whole picture. The wiki notes that "net inflation accounts for burned tokens through treasury expenditures and Coretime sales, making actual inflation less predictable than gross figures." In other words, DOT spent on blockspace and unspent treasury funds reduce the effective expansion, and how much they reduce it depends on demand rather than on a schedule.

The staking yield an individual nominator earns is a different number again. It depends on the total DOT staked network-wide, on the validator's commission, on that validator's uptime, and on whether any slashing occurred. A quoted apy from one era is not a promise about the next.

History

Polkadot's founding idea was that a single chain should not have to be everything. Instead of one execution environment that every application shares, Polkadot supplies consensus, data availability and scheduling, and lets each connected chain define its own state transition rules. A chain that wants privacy, or a different fee model, or an unusual virtual machine, can have it without recruiting its own validator set.

The wiki's framing of shared security is the load-bearing claim: "parachains connected to the relay chain all share in the security of the relay chain… Since the validator set on the relay chain is expected to be secure with a large amount of stake put up to back it, parachains should benefit from this security."

Two structural changes have reshaped the network since launch. The move from fixed-term parachain slot auctions to agile Coretime turned access into a purchase rather than a competition, lowering the entry cost for smaller teams. The migration of accounts, balances and staking off the relay chain and onto Asset Hub narrowed the relay chain to coordination alone, which is where the wiki says its value lies.

The November 2024 issuance change belongs in the same category. It replaced a compounding percentage with a fixed annual quantity, which makes long-run supply arithmetic something a holder can do without modeling the staking ratio.

Risks and what to watch

Validator concentration is the standing structural concern. Because rewards are paid equally per validator rather than per unit of stake, the economics push against concentration, but the actual distribution of stake and the number of independent operators are worth checking rather than assuming.

Staked DOT is not liquid on demand. Unbonding takes time, and the wiki points to its chain state values page for the current duration rather than fixing it in prose, so the figure is omitted here. Anyone planning around an unbonding period should read the current value before bonding.

Governance is a real dependency, not a ceremony. Inflation, fees and code upgrades are all decided by DOT holders, and a holder is exposed to those decisions whether or not they participate.

Demand for Coretime is the variable that connects usage to the token. Coretime sales burn DOT, so a quiet network burns less and a busy one burns more. That is a healthier link between activity and supply than a fixed fee schedule, and it also means the offset to issuance is not something a holder can rely on in advance.

Frequently asked questions

How much new DOT is created each year?

From November 2024 the network issues a fixed 120,000,000 DOT per year, split 85% to stakers and 15% to the treasury. Because the quantity is fixed rather than the percentage, the inflation rate declines as supply grows.

Does DOT have a maximum supply?

The Polkadot Wiki states no supply cap. It describes a fixed annual expansion offset by burns from treasury expenditures and Coretime sales, and notes that net inflation is therefore less predictable than the gross figure.

What is Coretime?

The capacity a chain buys to have its blocks validated by Polkadot. Chains can hold a dedicated core or buy on-demand access shared with others, and both are paid for in DOT under the agile Coretime mechanism.

Where can you buy Polkadot?

Availability depends on your country or US state. See where to buy Polkadot for the exchanges serving your jurisdiction, and Exchanges to compare fees, kyc requirements and supported payment methods.