How does Polkadot process a transaction?
Polkadot processes transactions on parachains while the relay chain secures them; DOT transfers run on the relay chain, where validators finalize.
Vahe HakobyanEditor-in-chief
Updated Oct 6, 20263 min readFact-checked
On this page
- A finalized block cannot be undone, so keep your records.
- A collator orders parachain transactions and proves the block.
- Relay validators check that proof and finalize the block.
- Native DOT transfers are handled by the relay chain.
Polkadot splits the work between two kinds of chain. Parachains execute the transactions sent to them and the relay chain secures those blocks, while a native DOT transfer runs on the relay chain itself. Sending either one takes a Polkadot wallet, a recipient address on the right chain, and the chain's fee token.
What do you need before you start?
Each parachain can use its own address format and keep its own transaction history, so one wallet may not cover all of them. Gather these items before you submit anything.
- A wallet that supports Polkadot and the parachain you plan to use.
- The recipient address for that chain.
- The parachain name or ID.
- Enough of the fee token that chain uses: DOT on the relay chain, often the parachain's own token otherwise.
- A backup of your seed phrase.
How does Polkadot process a transaction?
A parachain transaction moves from your wallet to a collator, and then to relay chain validators, who make it final. The steps follow that order.
- 1Sign the extrinsicYour wallet signs the instruction with your key. That signature authorizes the network to act.
- 2Submit it to the networkFor a parachain transaction, your wallet sends it to a collator on that parachain. A native DOT transfer goes to relay-chain validators instead.
- 3Let the collator order itThe collator places your transaction in a parachain block and produces proof that the block is valid. That proof goes to the relay chain.
- 4Relay validators verify itThey check the proof and finalize the parachain block. Finalized means the result is settled.
- 5Wait for finalityFor a parachain transaction, finality arrives after that verification. A DOT transfer is finalized by relay validators directly.
- 6Check the confirmationLook the transaction up in the explorer for the chain that executed it, the parachain for a parachain transfer or the relay chain for DOT.
What should you do after confirmation?
A finalized block cannot be undone, so your own records are how you trace the transaction later. Buying crypto with US dollars is not a taxable event, but the IRS treats cryptocurrency as property, so trading one crypto for another or paying with crypto usually is.
Frequently asked questions
For a parachain transaction, finality comes once relay chain validators verify the proof for the block. Wallet confirmations in Polkadot are usually quick, and a DOT transfer is finalized by relay validators directly.
An extrinsic is a signed instruction from your wallet that asks the network to do something. Once a block includes it, it is recorded as a transaction.
No. Once a block is finalized, the transaction cannot be undone and a payment sent to a wrong address cannot be pulled back. Before finality, it may simply not be included.
Wallets built for Polkadot usually support DOT on the relay chain, and some also support particular parachains. Check the wallet's chain list before you use it on a parachain.
