How can you check whether a layer 2 or a bridge is safe enough to use?

Question 1: Where does it keep its data?

ethereum.org says one clear test is whether a network stores its data on Ethereum's main network. Projects that do are often called rollups.¹ Sidechains and validiums do not get their security or their data from Ethereum.⁴

ethereum.org warns that many layer 2 projects are still young and somewhat experimental. No layer 2 is as battle-tested as Ethereum's main network.⁴

Question 2: Who can change it or stop it?

L2BEAT, a site that tracks the risks of layer 2s, rates rollups in "Stages".² ethereum.org points readers to L2BEAT for its risk assessment of each project.⁴

• Stage 0: fully controlled by a few people or companies.²
• Stage 1: somewhere in between.²
• Stage 2: fully controlled by its code.²

To reach Stage 2, a rollup must give users at least 30 days to leave before an unwanted upgrade.² If it uses fraud proofs, anyone must be able to submit them, not just an approved list.²

L2BEAT warns that Stages measure decentralisation, not security. It is very easy, it says, to launch a very unsafe project that still counts as Stage 2.²

ethereum.org builds its own labels on these stages. A "Robust" network must be Stage 2, while an "Emerging" network is Stage 0 and run by a central operator.⁵

Question 3: How do I get my money out?

• Optimistic rollup, own bridge: expect to wait roughly seven days, or pay a liquidity provider a fee to be paid sooner.³
• ZK rollup: no challenge wait once the proof is verified.⁶
• If the operator ignores you: rollups let users send transactions straight to the rollup's contract on Ethereum.^3,6

Question 4: Which bridge, and who runs it?

With a trusted bridge, you rely mostly on the operator's reputation.⁷ Its operators could, in theory, stop transfers or work together to steal funds.⁷ ethereum.org points to L2BEAT's risk analysis of bridges to help people choose.⁷

Question 5: Am I on the real site, with the right amount?

• Check you are on the right website address, especially after clicking a link.⁸
• Read what a transaction does before you sign it.⁸
• Before you confirm, check how much you will receive and what the fees are.⁹
• Start with a small transaction.¹
• Remember that a transaction sent on Ethereum can't be reversed.⁸

Before the quiz