Plasma
A layer 2 scaling design that moves transactions to child chains while using the main blockchain for security and dispute resolution.
Plasma is a layer 2 scaling framework, most associated with Ethereum, that creates separate “child chains” connected to a main blockchain. Transactions happen on the child chain, and only compact summaries or commitments are posted to the main chain. If something goes wrong, users can challenge invalid activity and withdraw their funds back to the main chain through an exit process. This lets many transactions be processed without every detail being executed directly on the base layer.
Plasma matters because it was an early approach to making blockchains cheaper and faster for use cases like payments, token transfers, and simple exchange activity. For example, a game or payment app could process frequent small transfers on a Plasma chain, then rely on Ethereum only for final settlement and disputes. Compared with rollups, Plasma generally places more responsibility on users to monitor the chain and exit if data is withheld or fraud occurs, which made it less flexible for complex smart contracts. Still, it remains an important concept in layer 2 scaling history.
Other terms in Layer 2 & Scaling
Data Availability
The assurance that the transaction data needed to verify a blockchain or layer 2 network can be accessed by anyone who needs it.
Fraud Proof
A fraud proof is evidence submitted to a blockchain to show that a proposed transaction result or rollup state is invalid.
Layer 2
A Layer 2 is a secondary network or protocol built on top of a blockchain to process transactions faster and cheaper while relying on the main chain for security.
Layer 3
A Layer 3 is an application-specific blockchain layer built on top of a Layer 2 to add customization, scalability, or specialized features.