What is Scalability?

Scalability is a blockchain's ability to handle growing transaction volume while keeping fees low and maintaining decentralization. Bitcoin processes roughly 7 transactions per second; Ethereum roughly 15 far below the thousands needed for mainstream use.

How does Scalability work?

Layer 2s execute transactions off-chain and settle batches on Layer 1, boosting throughput dramatically.
Sharding divides the blockchain into parallel chains, each processing transactions independently.
Improved consensus mechanisms like Proof of Stake reduce overhead versus Proof of Work.
Sidechains run parallel chains with their own validators and lower costs.

Why does Scalability matter?

Without it, high fees and slow confirmations make blockchains impractical for everyday use and mass adoption.

Key features of Scalability

Measured in transactions per second (TPS)
Every solution trades off security, decentralization, or complexity
Layer 2s are the dominant near-term solution for Ethereum
Sharding is Ethereum's long-term approach

Examples of Scalability

Arbitrum and Optimism process 1000+ TPS while settling to Ethereum for security. Solana achieves higher raw throughput but with greater centralization trade-offs.