On-chain
Also known as: onchain, on the chain
Describing transactions or activity recorded directly on a blockchain, as opposed to off-chain activity held only in a provider's internal records.
Definition
On-chain means an action is settled and recorded on the blockchain itself, visible to anyone and permanent. Off-chain activity — such as internal exchange trades — is not written to the chain and lives in the provider's ledger. For tax, on-chain data lets you independently verify transfers and disposals via public addresses, while off-chain activity relies on exchange statements you must import and reconcile.
Example
A withdrawal from an exchange to your wallet is on-chain and traceable; a trade inside the exchange may be off-chain, visible only in your statement.