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Solidity Support

Arbitrum Nitro chains are Ethereum compatible, and therefore allow you to trustlessly deploy Solidity contracts (as well as Vyper or any other language that compiles to EVM bytecode).

Differences from Solidity on Ethereum

Although Arbitrum supports Solidity code, there are differences in the effects of a few operations, including language features that don't make much sense in the Layer 2 context:

  • blockhash(x) returns a cryptographically insecure, pseudo-random hash for x within the range block.number - 256 <= x < block.number. If x is outside of this range, blockhash(x) will return 0. This includes blockhash(block.number), which always returns 0 just like on Ethereum. The hashes returned do not come from L1.
  • block.coinbase returns zero
  • block.difficulty returns the constant 2500000000000000
  • block.number return an "estimate" of the L1 block number at which the Sequencer received the transaction (see Block Numbers and Time)
  • msg.sender works the same way it does on Ethereum for normal L2-to-L2 transactions; for L1-to-L2 "retryable ticket" transactions, it will return the L2 address alias of the L1 contract that triggered the message. See retryable ticket address aliasing for more.