Transaction processing refers to the mechanism that validates and records transactions within a blockchain. When a user initiates a transaction, such as sending coins to another party, the details of this action need to be verified against existing data before being added to the blockchain.The process typically involves several steps. First, the transaction is broadcast to a network of nodes, which are computers that maintain a copy of the blockchain. These nodes work to ensure the transaction is legitimate, checking for issues like insufficient balance or incorrect signatures.Once verified, the transaction is grouped with others into a block. Miners, or validators depending on the protocol, then compete to add this block to the blockchain. This competition usually requires solving complex mathematical problems or validating prior data. After being added, the transaction becomes part of the immutable ledger, making it permanent and accessible to anyone. This ensures transparency and trust in the system, as all participants can confirm the transaction history without needing a central authority.