Layer 2 blockchain · settles to Ethereum
Arbitrum One ticker ARB
Summary
Optimistic rollup on Ethereum. A sequencer orders transactions and posts batches to the Sequencer Inbox contract on Ethereum; validators post assertions about L2 state backed by a bond (minimum 3600 ETH). The BoLD dispute protocol is active on Arbitrum One and lets anyone challenge an incorrect assertion; assertions confirm after a challenge period of 45818 L1 blocks (about 6.4 days). Block production does not use its own stake or work. The core contracts are upgradable: DAO proposals pass through timelocks, and a 9-of-12 Security Council multisig can upgrade without delay in an emergency. 14671415
Design
- System
- Layer 2 blockchainArbitrum One (chain ID 42161) is an optimistic rollup on Ethereum running the Nitro stack. ETH is the gas asset; ARB is a governance token. Arbitrum Nova (AnyTrust) and other Arbitrum-branded chains are separate networks not described here.
- Settles to
- EthereumBatches are posted to Ethereum and assertions confirm there after about 6.4 days if unchallenged; deposits and forced transactions enter via the delayed inbox on Ethereum. The DAO can change the challenge window, and the Ethereum-side contracts can be upgraded by DAO governance or, in an emergency, by the Security Council without delay.
- Settlement family
- Ethereum / EVM
- Scarce resource
- Other
- State model
- Accounts
- Finality
- Other
- Who makes blocks
- A single centralized logical sequencer (several nodes behind one leader-elected sequencer), maintained by Offchain Labs according to the Arbitrum FAQ. Its policy is set by the chain owner, the Arbitrum One Upgrade Executor, which only the Security Council and DAO governance (through the L1 timelock) can call. Users can bypass the sequencer through the delayed inbox on Ethereum after at most 24 hours.
- Fork choice
- No open L2 fork choice: transaction order comes from the sequencer and the delayed inbox on Ethereum, and state claims are settled by BoLD interactive fraud proofs on Ethereum.
Qualifications
- Scarce resource · Not applicable. Arbitrum One block production uses no stake or work of its own; assertion bonds secure disputes, and security is derived from Ethereum plus BoLD.
- Finality · Partial. An L2 receipt reports sequencer inclusion only; settlement anchored on Ethereum follows batch posting and assertion confirmation, so Arbitrum One's finality does not fit the standard finality categories used for base-layer chains.
- Network scope · Not applicable. Arbitrum Nova (AnyTrust data-availability committee) and dedicated Arbitrum chains have separate identities and trust assumptions and are outside this profile.
Tradeoffs
- Emphasizes
- Scalability and Security
- Gives up
- Decentralized sequencing and upgrade neutrality: one centralized sequencer maintained by Offchain Labs orders transactions, and forced inclusion via Ethereum can take up to 24 hours. A 9-of-12 Security Council can upgrade core contracts without delay in emergencies, and used this in April 2026 to move about 30,766 ETH out of an exploiter's address on Arbitrum One. Withdrawals to Ethereum take about a week.The security emphasis rests on Ethereum settlement and permissionless BoLD fraud proofs, qualified by the Security Council's instant emergency upgrade power. The 3600 ETH assertion bond and the DAO's power to change the challenge window are also part of the trust model, and BoLD gives the Security Council a two-day grace period to intervene in disputes. A ZK settlement roadmap is not active from the reviewed evidence.
- Full node at home
- Demanding 8Arbitrum's full-node docs give Arbitrum One snapshot sizes of about 2.3 TB (pruned HashDB) and 2.4 TB (PathDB), and a node needs an Ethereum RPC and beacon endpoint. CPU and RAM minimums were not found in the reviewed pages.
- Throughput claims
- No classified figure recorded
Scaling layers
No scaling layer recorded in this profile.
Capabilities
| Capability | How it is provided | Notes and sources |
|---|---|---|
| Account abstraction | Structured assessment pending | Not yet assessed for any chain. |
| Atomic swaps | Independent softwareLimited scope | Garden, a third-party swap service, settles cross-chain swaps through hashed time-locked contracts (HTLCs): a swap either completes on both chains or can be refunded. Its supported-chains page lists Arbitrum (WBTC and iBTC) among its mainnet chains. The protocol has no built-in swap, and no Offchain Labs or Arbitrum Foundation swap tool is cited. Limited: only the assets Garden lists. Contract risk, liquidity and other hash-locked swap services on Arbitrum One were not reviewed. 2122 |
| Authenticated data publication | Unknown | Not yet assessed under this row's current definition. |
| Light clients | Unknown | A light-client verification path for Arbitrum One was not reviewed. |
| Native staking or delegation | Structured assessment pending | Not yet assessed for any chain. |
| On-chain governance | Structured assessment pending | Not yet assessed for any chain. |
| Parallel execution | Structured assessment pending | Not yet assessed for any chain. |
| Payment or state channels | Unknown | No payment or state channel layer anchored to Arbitrum One was reviewed. |
| Programmable spending | Native (protocol or core-team software) Earlier definition | Nitro runs EVM-compatible contracts, and Stylus adds WASM-targeting languages such as Rust. 35 |
| Protocol-verified messaging | Structured assessment pending | Not yet assessed for any chain. |
| Reversible transfers or recovery | Unknown | Not yet assessed under this row's current definition. |
| Rollups | Unknown | Rollups anchored to Arbitrum One (L3s) were not reviewed. Arbitrum One itself is a rollup on Ethereum; see the mechanism and Ethereum-dependency sections of this profile. |
| Shielded transfers | Structured assessment pending | Not yet assessed for any chain. |
| Signed partial offers | Unknown | Not yet assessed under this row's current definition. |
Reading these values
- How this feature is provided
- Built into the protocol, core-team software or independent software says where a feature lives and who can change it. These are implementation layers, not quality: core-team software is not closer to the protocol than independent software.
- Structured assessment pending
- The shared review has not assessed this feature for any chain yet (Account abstraction, Native staking or delegation, On-chain governance, Parallel execution, Protocol-verified messaging and Shielded transfers). That does not mean it is absent, and a chain’s profile may already describe it.
- Unknown
- The review has not established this for this chain under the current definition; the note beside it says why. Unknown is not absent and not a low score. A feature reads “Not present” only when a source shows it is absent.
- Earlier definition
- Payment or state channels, Programmable spending and Rollups keep the earlier definition until the next fact-check. There, “Native” does not separate the protocol from core-team software, “Ecosystem software” does not say who publishes it, and “Partial” does not say which layer.
- Reading across rows
- The list of capabilities is incomplete. Do not read these rows as a chain leading or lagging overall.
Ecosystem & custody
| Product type | Status | Notes and sources |
|---|---|---|
| Automated market makers | Established in the ecosystemCamelot | Camelot documents a decentralized exchange and liquidity protocol founded on Arbitrum One. Liquidity depth was not measured and other venues were not reviewed. 9 |
| Issuer-native stablecoins | Established in the ecosystemUSDC (Circle) | Circle lists natively issued USDC on Arbitrum One (0xaf88d065e77c8cC2239327C5EDb3A432268e5831). Native means issuer-issued on Arbitrum One, not a protocol asset. 10 |
| Algorithmic stablecoins | Unknown | Algorithmic or hybrid stablecoins on Arbitrum One were not reviewed. |
| Bridges | Native to the protocolArbitrum canonical bridge (Delayed Inbox, Bridge and Outbox contracts on Ethereum) | Deposits enter through the delayed inbox on Ethereum. A withdrawal is a message from Arbitrum One that anyone can execute on Ethereum through the Outbox contract, with a proof of inclusion, once the assertion containing it is confirmed. Arbitrum's bridge guide says withdrawals take at least seven days (shown as a 7-8 day countdown), because the 6.4-day (45818-block) challenge period must pass first. Third-party bridges were not reviewed. Risk: Withdrawals rely on at least one honest BoLD challenger. If the assertion covering a withdrawal is disputed, BoLD caps resolution at two challenge periods plus a two-day Security Council grace period, roughly 15 days. A 9-of-12 Security Council can upgrade the Delayed Inbox, Bridge and Rollup contracts on Ethereum without delay in an emergency. It used this in April 2026 to upgrade the Delayed Inbox and move about 30,766 ETH out of an exploiter's address on Arbitrum One, and in May 2026 to patch Bridge.executeCall(). The DAO can change the challenge window. 12615161718 |
| Block explorers | Established in the ecosystemArbiscan, Blockscout (arbitrum.blockscout.com) | Arbitrum's chain-information page lists both explorers for Arbitrum One. Explorer indexes are not canonical consensus. 1 |
| Hardware wallets | Established in the ecosystemTrezor (Safe 3, 5, 7), Ledger (Ethereum app) | See the custody section: Trezor lists Arbitrum One as a supported network, and Ledger's Arbitrum page points users to an Arbitrum account in Ledger Wallet, signed with the device's Ethereum app. The Ledger reading is lower confidence because Ledger's current code keeps Arbitrum behind a feature switch that is off by default. 11121924 |
Hardware-wallet custody
| Device maker | Status | What users can and cannot do |
|---|---|---|
| Ledger | Native supportSame as native: Unknown | Can: Set up an Arbitrum account in the Ledger Wallet app (formerly Ledger Live), per Ledger's Arbitrum coin page Can: Sign with the device's Ethereum app: Ledger's wallet code defines Arbitrum as an EVM account on chain 42161 with ETH as the currencyLower confidence. Current Ledger Wallet code has an Arbitrum module behind a feature switch that is off by default in code; as for other networks judged under the same custody rule, Ledger's templated Arbitrum coin page telling users to set up an account in Ledger Wallet is taken as the sign the switch is on for users. Ledger's support article could not be read, so ARB and ERC-20 token handling is not listed. An older tagged release (desktop 2.64.2) also marked Arbitrum as supported. 111920232425 |
| Trezor | Native supportSame as native: Unknown | Can: Use the Arbitrum One network with Trezor Safe 3, Safe 5 and Safe 7, per Trezor's Arbitrum pageTrezor's page lists Ethereum, Arbitrum One and Arbitrum Nova as supported networks for the Safe models; token and contract-interaction coverage was not reviewed. 12 |
Public data
Your AI can request these lookups through the connection. The website itself runs no lookups. Networks: mainnet.
| Lookup | Status | What it covers and its limits |
|---|---|---|
| Address or account | Available | native ETH balance, transaction count and code presence at provider-reported latest state |
| Tokens and assets | Available | paginated Blockscout-indexed ERC-20 and aggregate ERC-721/ERC-1155 balance rows |
| NFTs | Available | paginated Blockscout-indexed ERC-721/ERC-1155 token IDs and exact quantities |
| Transactions | Available | transaction and receipt execution from the fixed public RPC |
Sourced developments
Developments: Review overdue Reviewed Sep 26, 2026; next review was due Oct 6, 2026.
Publication date · newest first
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Nitro v3.11.4 was released
Offchain Labs published Nitro v3.11.4 on GitHub on September 16 (its release notes carry a September 9 version date) with bounded proof and fee-history request behavior plus fixes. A node-software release does not itself prove deployment or activation on Arbitrum One.
- Type:Release
- Proposal:Not applicable
- Release:Released
- Activation:Not established by release
Source: Offchain Labs — Arbitrum Nitro v3.11.4 (external site)
-
ArbOS 61 Elara activated on Arbitrum One
Official documentation records governance approval and activation at 17:00 UTC, with One-specific minimum-base-fee management and a 96 KB Stylus limit. Priority-fee collection, compliance filtering and AltDA were not enabled on One by this activation.
- Type:Upgrade
- Proposal:Governance approved
- Release:Released
- Activation:Activated mainnet
Sources: Arbitrum Foundation — ArbOS Elara: Compliance Filtering, Priority Fee Support (external site) · Arbitrum Documentation — ArbOS 61 Elara (external site)
-
Arbitrum described a roadmap toward ZK settlement
An official Arbitrum blog post with an individual author byline described engineering milestones and said Offchain Labs would bring a future DAO proposal, which would be required to upgrade Arbitrum One. Roadmap publication is not production activation.
- Type:Roadmap
- Proposal:Roadmap before dao proposal
- Release:Not established
- Activation:Not active from this evidence
Source: Arbitrum Foundation — ZK Settlement is Coming to Arbitrum (external site)
-
Nitro v3.11.3 was released for ArbOS 61 operators
Offchain Labs published Nitro v3.11.3 on GitHub on August 12 (its release notes carry an August 3 version date), and the ArbOS 61 documentation identifies it as the minimum mandatory version for Arbitrum One and Nova node operators ahead of Elara activation. The client release alone is not activation evidence.
- Type:Release
- Proposal:Not applicable
- Release:Released
- Activation:Not established by release
Sources: Offchain Labs — Arbitrum Nitro v3.11.3 (external site) · Arbitrum Documentation — ArbOS 61 Elara (external site)
Topics your AI can explain
Your AI can explain these topics for Arbitrum One through the connection, with sources.
Known gaps
What this profile's review did not establish:
- Whether Arbitrum governance has since released or reassigned the ETH frozen by the Security Council in April 2026, and whether the Council used emergency powers again after May 2026, were not reviewed.
- CPU and RAM minimums for an Arbitrum One full node were not found; the home full-node assessment relies on published snapshot sizes.
- Ledger's support article on Arbitrum (support.ledger.com) is script-rendered and could not be read. Current Ledger Wallet code keeps Arbitrum behind a feature switch that is off by default and Ledger's remote switch settings are not public, so reading it as full support rests on Ledger's templated Arbitrum coin page plus an older tagged release (desktop 2.64.2); ARB and ERC-20 token handling appeared only in search snippets and is not listed as verified.
- Trezor coverage of older models (Model One, Model T) and of tokens and contract calls on Arbitrum One was not reviewed.
- No scaling options built on Arbitrum One (L3 rollups, channels) were reviewed, so this profile lists none.
- The ZK settlement roadmap was described by Arbitrum in August 2026 but requires a future DAO proposal; it is not reflected as active.
- Reversible or delayed transfers, account recovery, light clients and algorithmic stablecoins on Arbitrum One were not reviewed; for atomic swaps only Garden's listing was checked.
- Third-party bridges (e.g. Circle CCTP) and venues other than Camelot were not reviewed.
Sources
Oldest dated source check: Source checked Sep 25, 2026 Next check due Oct 25, 2026.
- Arbitrum chain information (external site)
- Quickstart: Arbitrum bridge (external site)
- Arbitrum Nitro (external site)
- Arbitrum Nitro: A Second-Generation Optimistic Rollup (external site)
- A gentle introduction to Stylus (external site)
- A gentle introduction to BoLD (external site)
- The Sequencer and censorship resistance (external site)
- How to run a full node for an Arbitrum chain (external site)
- Camelot Documentation: Overview (external site)
- USDC Contract Addresses (external site)
- Arbitrum wallet (external site)
- Arbitrum wallet (external site)
- ZK Settlement is Coming to Arbitrum (external site)
- Arbitrum FAQ (external site)
- Arbitrum Governance (docs/overview.md) (external site)
- Security Council Emergency Action – 21/04/2026 (external site)
- Security Council Emergency Action – 24/05/2026 (external site)
- Child to parent chain messaging (external site)
- Ledger Live crypto-asset definitions (cryptoassets currencies.ts, tag @ledgerhq/[email protected]) (external site)
- Supported crypto assets (Ledger Live desktop cryptoassets.md, tag @ledgerhq/[email protected]) (external site)
- HTLCs (external site)
- Supported Chains and Assets (external site)
- Ledger Wallet coin-module loaders (loaders.ts, develop branch) (external site)
- Ledger Wallet feature switch currencyArbitrum (develop branch) (external site)
- Ledger feature-flag definitions (define.ts): a switch declared with no value is off by default (external site)
Report an error
Found something wrong or out of date? Reporting is free, and every chain goes through the same process. Published corrections appear in the public log.
Funding disclosure
Funding disclosures appear here when an upkeep arrangement exists, in the form “Upkeep funded by [name]; verdicts unaffected.” The funder ledger has not been published yet. Neutrality & funding