Scalability and the blockchain trilemma
Why blockchains are slower than Visa, and the honest trade-offs behind every "faster" chain.
The blockchain trilemma is the observation that a simple blockchain finds it hard to be very scalable, very secure and very decentralized at the same time. Handling more transactions usually means each node needs more powerful hardware, so fewer people can run one. Bitcoin and Ethereum favor decentralization and security on their base layers and push scale to layer 2s; some newer chains accept heavier hardware for more speed.
The three corners
- Scalability: how many transactions the network can handle, and how cheaply.
- Security: how much it would cost to attack it, for example to rewrite history or censor transactions.
- Decentralization: how many independent people can check and take part, which mostly depends on how cheap it is to run a full node.
The tension comes from one fact: in a basic blockchain, every full node processes every transaction. Double the throughput and every node needs roughly double the bandwidth, storage and computing power.
Example: why not just make blocks bigger?
That was the argument behind Bitcoin Cash in 2017. Bigger blocks do carry more transactions. But every node must download and store them forever, so over time fewer people can afford to run one, and checking the rules shifts toward data centers. Bitcoin's community chose small blocks and layer 2s (Lightning); Bitcoin Cash chose bigger blocks. Neither is "correct"; they weigh the corners differently.
How different networks choose
| Approach | Examples | Trade-off |
|---|---|---|
| Small base layer, scale on top | Bitcoin + Lightning; Ethereum + rollups | Cheap to verify; users juggle extra networks and bridges |
| Fast base layer, heavy hardware | Solana | High throughput; validators need powerful servers and fast connections |
| Small, known validator set | BNB Chain, Tron, permissioned ledgers | Fast and cheap; trusts a few dozen block producers |
| Many chains, shared security | Polkadot, Cosmos | Scales across chains; more moving parts |
Ways around it
- Layer 2s do the heavy work off the base chain and use it only for settlement and data. See layer 1 vs. layer 2.
- Data availability sampling. Since Fusaka (December 2025), Ethereum nodes check random samples of rollup data instead of downloading all of it, so capacity can grow without every node doing more work.
- Zero-knowledge proofs let one party do a large computation and everyone else check a small proof. See zero-knowledge proofs.
- Better software: faster clients, better compression and gradual gas-limit increases as hardware improves.
Limits of the idea
- It's a rule of thumb, not a mathematical theorem. Clever designs move the boundary.
- Decentralization has no single number. Node counts, stake distribution, client diversity and who controls upgrades all matter.
- Transactions-per-second claims are often peak lab numbers. Compare real, sustained use, and ask what a node costs to run.
Frequently asked questions
Who came up with the blockchain trilemma?
The term was popularized by Ethereum co-founder Vitalik Buterin, who described it in his writing on sharding and scaling.
Why is Bitcoin so slow?
Bitcoin deliberately keeps blocks small and about 10 minutes apart so ordinary computers can verify the whole chain. Faster payments are meant to use layers such as Lightning.
Has any blockchain solved the trilemma?
No network has convincingly maximized all three on one layer. Layer 2s and data availability sampling are the main attempts to get close.
Is a higher TPS always better?
No. High throughput can come from fewer, more powerful validators, which trades away decentralization. Ask what it costs to run a node.
Where to next
Sources
- Scaling (ethereum.org)
- Why sharding is great: demystifying the technical properties (Vitalik Buterin, 2021)
- Danksharding and PeerDAS (ethereum.org)
- Ethereum forks timeline (ethereum.org)
- Bitcoin white paper
Written for beginners and checked against the sources listed. Last reviewed November 4, 2026. This page is educational and is not financial, tax or legal advice. How we write and check pages.