The scalability concerns facing blockchain technology and how they’re being addressed
Fares
Why busy blockchains get slow and expensive, and how rollups, sharding and payment channels try to fix it.
Every full node on a blockchain checks every transaction. That is what makes the network trustworthy, and it is also why throughput is limited: Bitcoin handles a handful of transactions per second and Ethereum's main chain only a few dozen.
The trade-off
Raising block size or speed makes nodes harder to run, which pushes the network towards fewer, larger operators. Designers call this the scalability trilemma: security, decentralisation and speed pull against each other.
How it is being addressed
- Rollups bundle thousands of transactions off-chain and post a compact proof to the main chain.
- Sharding splits data so that no node has to store everything.
- Payment channels such as Lightning settle many small payments with two on-chain transactions.
What it means for you
Fees on layer-2 networks are now cents rather than dollars. The open question is how smoothly money and apps move between all these layers.