What Arbitrum is
Arbitrum One is a layer 2 network for Ethereum. It is an optimistic rollup: it runs transactions off Ethereum, posts them to Ethereum in batches, and treats each result as valid unless it is challenged. It launched in 2021 on technology built by Offchain Labs; the Arbitrum DAO, made up of ARB holders and their delegates, governs it, and the Arbitrum Foundation operates it.
It works with Ethereum's wallets, tools and smart contracts unchanged, and tokens move between it and Ethereum through bridges. Teams that want Ethereum for settlement and security, with quicker transfers, use it, which is why it is one of the Ethereum layer twos our custody module supports.
What it does in your platform
Custody & wallets
Gives each customer an Arbitrum One address for ETH and the tokens you list there, credits deposits under the finality rule you choose, and signs withdrawals under policy. As an EVM chain, it runs on the same connector as Ethereum, with its own settings.
How the connection works
The module reads Arbitrum One over the same JSON-RPC interface as Ethereum, from your own node or a node provider such as Infura, Alchemy or QuickNode, and signs through your custody provider or your own keys.
An address per customer
The module gives the customer an Arbitrum One address, which receives ETH and every token you support there.
The sequencer orders it
Arbitrum's sequencer orders transactions into blocks and gives a soft confirmation in under a second, which relies on the sequencer behaving honestly.
Posted to Ethereum
The sequencer's batches are posted to Ethereum, and once Ethereum finalises them, the transactions reach hard finality.
Counted under your rule
Your rules decide which one a deposit waits for: the quick soft confirmation, or hard finality on Ethereum.
Screened and credited
The deposit is screened and credited, and the movement appears in the backoffice.
A withdrawal signed
After limits, screening and approvals, the transaction is signed by your custody provider or your own keys, sent to the network and reconciled.
Next to other chains
Arbitrum shares Ethereum's address format and node interface, so it runs on the module's EVM connector with its own node access, tokens and finality rule, under the same policies, approvals, screening and reconciliation as every other chain.
ETH on Arbitrum and ETH on Ethereum are separate balances on separate chains, and the ledger keeps them apart. Moving treasury funds from Arbitrum back to Ethereum through its own bridge takes about a week, because of the challenge period, so those moves are planned ahead.
When Arbitrum fits best
A strong fit when
- Your customers use Ethereum tokens and want quicker transfers on a layer 2.
- You already run Ethereum and want its layer twos with little extra work.
- You want a quick soft confirmation for everyday deposits, with Ethereum finality there when you need it.
Also worth a look
- Base, another Ethereum layer 2, if your customers are there.
- Ethereum itself, for large transfers and tokens that live only there.
How we get you live
Node access
We connect the module to Arbitrum One through your own node or a node provider such as Infura, Alchemy or QuickNode.
Custody and tokens
We check that your custody provider supports Arbitrum One and each token you list, by its contract address on Arbitrum, or set up your own keys.
Finality rule
We agree with you whether deposits count at soft confirmation or wait for hard finality on Ethereum.
A testnet run
The whole flow runs on Arbitrum Sepolia, its testnet, before real funds move.
