On-chain transactions refer to Bitcoin transactions that occur on the blockchain and remain dependent on the state of the blockchain for their validity. On-chain transactions are considered valid only when the blockchain has been updated to reflect the transactions on the public ledger, such as a confirmation. On-chain transactions offer security and transparency since they can’t be altered once they’re verified and recorded on the network, they are immutable. However, there are some drawbacks to on-chain transactions, which include higher fees and slow processing times.