Layer 2 or Ethereum mainnet: what to build on
A layer 2 executes transactions itself and sends their data to Ethereum, so an action there is usually cheaper while security rests on mainnet. The Solidity code is almost the same everywhere; the differences are withdrawals, who runs the network and where your users already are.
Same Solidity, different trade-offsLayer 1 and layer 2 point by point
What changes for the product and the user.
| Layer 1 and layer 2 point by point | Mainnet (layer 1) | Layer 2 |
|---|---|---|
| What it is | Ethereum itself | A separate network that extends Ethereum |
| Security | Its own | Rests on Ethereum: transaction data is posted to layer 1 |
| Fee per action | Higher | Usually lower: transactions are batched |
| Withdrawal to layer 1 | Not needed | Through a bridge, with a challenge period on optimistic rollups |
| Code and tools | Solidity, Foundry, Hardhat | Usually the same: the networks are EVM-compatible |
How it works
From the ethereum.org and Polygon documentation, read on 15 November 2026.
- A layer 2 inherits security
A layer 2 extends Ethereum and inherits its security guarantees. Rollups send transaction data to layer 1 and execute the transactions themselves.[1]
- Optimistic and ZK rollups
Optimistic rollups assume transactions are valid and check disputed ones with fault proofs. ZK rollups post a proof of validity for the computation to layer 1.[1]
- Polygon PoS is a sidechain
Polygon PoS is described as an EVM-compatible proof-of-stake sidechain for Ethereum. It is often grouped with layer 2s, but its security model is its own.[2]
What we compare when choosing a layer 2
The code is the same; the rest is not.
Where to launch
Decided by what users do and how often.
- Actions are few, and each one matters
- The contract anchors other networks
- Partners work on mainnet only
- Actions are many and small
- Users would notice the mainnet fee
- Users already hold wallets on that layer 2
How we choose
A shortlist, tests, a decision.
- Shortlist
Two or three networks, by users, assets and flows.
- Test on each
Your contracts and the gas per action, network by network.
- Decide and design
Bridges, withdrawals and admin keys.
- Launch and monitor
Deployed from a multisig, then monitored. The development price is in the contract.
Read next
Networks, comparisons and terms.
Checked on 15 November 2026
This is not legal advice. Laws change: before launch, check the current version on adilet.zan.kz and talk to a lawyer or accountant.
Short and to the point.
How do Arbitrum, Optimism and Base differ?
All three are optimistic rollups that send their data to Ethereum. Optimism and Base are built on the OP Stack; Arbitrum has its own. For most contracts the code is the same; the ecosystems, bridges and governance differ.
Is Polygon a layer 2 like the others?
Polygon PoS is an EVM-compatible sidechain with its own validators, so its security model differs from a rollup’s. For many apps that is acceptable, but we explain the difference before you choose.
Can we deploy to several layer 2s at once?
Yes. The same Solidity usually deploys everywhere, but each network needs its own addresses, admin keys, indexing and monitoring, and transfers between them go through bridges. We start with one unless your users are split.
How much does a layer 2 build cost?
There is no separate price in our price list. We name it after the brief and fix it in the contract. Each extra network is priced as extra scope.
Do we need a licence because we use a layer 2?
Not because of the network. Developing software to order is not licensed; what counts is what the product does for users. The status for issuing, exchanging or holding digital assets is the client’s, and their lawyer decides it.
Which networks are you weighing?
Describe the product and users; we reply quickly with a shortlist.