Precompiles reference

ArbOS provides L2-specific precompiles with methods smart contracts can call the same way they can solidity functions. This reference page exhaustively documents the specific calls ArbOS makes available through precompiles. For a more conceptual description of what precompiles are and how they work, please refer to the precompiles conceptual page.

This reference page is divided into two sections. The first one lists all precompiles in a summary table with links to the reference of the specific precompile, along with the address where they live, their purpose and links to the go implementation and solidity interface. The second one details the methods available in each precompile with links to the specific implementation.

General information of precompiles

This section is divided into two tables. We first list precompiles we expect users to most often use, and then the rest of precompiles. However, both tables display the same information: name and purpose of the precompile, address, and links to the solidity interface and the go implementation.

Common precompiles

Precompile	Address	Solidity interface	Go implementation	Purpose
ArbAggregator	`0x6d`	Interface	Implementation	Configuring transaction aggregation
ArbGasInfo	`0x6c`	Interface	Implementation	Info about gas pricing
ArbRetryableTx	`0x6e`	Interface	Implementation	Managing retryables
ArbSys	`0x64`	Interface	Implementation	System-level functionality

Other precompiles

Precompile	Address	Solidity interface	Go implementation	Purpose
ArbAddressTable	`0x66`	Interface	Implementation	Supporting compression of addresses
ArbBLS	`0x67`	-	-	Disabled (Former registry of BLS public keys)
ArbDebug	`0xff`	Interface	Implementation	Testing tools
ArbFunctionTable	`0x68`	Interface	Implementation	No longer used
ArbInfo	`0x65`	Interface	Implementation	Info about accounts
ArbOwner	`0x70`	Interface	Implementation	Chain administration, callable only by chain owner
ArbOwnerPublic	`0x6b`	Interface	Implementation	Info about chain owners
ArbosTest	`0x69`	Interface	Implementation	No longer used
ArbStatistics	`0x6f`	Interface	Implementation	Info about the pre-Nitro state

Precompiles reference

ArbAddressTable

ArbAddressTable (Interface | Implementation) provides the ability to create short-hands for commonly used accounts.

Method	Solidity interface	Go implementation	Description
`addressExists(address addr)`	Interface	Implementation	AddressExists checks if an address exists in the table
`compress(address addr)`	Interface	Implementation	Compress and returns the bytes that represent the address
`decompress(bytes calldata buf, uint256 offset)`	Interface	Implementation	Decompress the compressed bytes at the given offset with those of the corresponding account
`lookup(address addr)`	Interface	Implementation	Lookup the index of an address in the table
`lookupIndex(uint256 index)`	Interface	Implementation	LookupIndex for an address in the table by index
`register(address addr)`	Interface	Implementation	Register adds an account to the table, shrinking its compressed representation
`size()`	Interface	Implementation	Size gets the number of addresses in the table

ArbAggregator

ArbAggregator (Interface | Implementation) provides aggregators and their users methods for configuring how they participate in L1 aggregation. Arbitrum One's default aggregator is the Sequencer, which a user will prefer unless SetPreferredAggregator is invoked to change it.

Compression ratios are measured in basis points. Methods that are checkmarked are access-controlled and will revert if not called by the aggregator, its fee collector, or a chain owner.

Method	Solidity interface	Go implementation	Description
⚠️`getPreferredAggregator(address addr)`	Interface	Implementation	Deprecated: Do not use this method.
⚠️`getDefaultAggregator()`	Interface	Implementation	Deprecated: Do not use this method.
`getBatchPosters()`	Interface	Implementation	GetBatchPosters gets the addresses of all current batch posters
`addBatchPoster(address newBatchPoster)`	Interface	Implementation	Adds newBatchPoster as a batch poster
`getFeeCollector(address batchPoster)`	Interface	Implementation	GetFeeCollector gets a batch poster's fee collector
`setFeeCollector(address batchPoster, address newFeeCollector)`	Interface	Implementation	SetFeeCollector sets a batch poster's fee collector (caller must be the batch poster, its fee collector, or an owner)
⚠️`getTxBaseFee(address aggregator)`	Interface	Implementation	Deprecated: returns 0
⚠️`setTxBaseFee(address aggregator, uint256 feeInL1Gas)`	Interface	Implementation	Deprecated: does nothing

Note: methods marked with ⚠️ are deprecated and their use is not supported.

ArbBLS

Disabled

This precompile has been disabled. It previously provided a registry of BLS public keys for accounts.

ArbDebug

ArbDebug (Interface | Implementation) provides mechanisms useful for testing. The methods of ArbDebug are only available for chains with the AllowDebugPrecompiles chain parameter set. Otherwise, calls to this precompile will revert.

Method	Solidity interface	Go implementation	Description
`becomeChainOwner()`	Interface	Implementation	Caller becomes a chain owner
`events(bool flag, bytes32 value)`	Interface	Implementation	Emit events with values based on the args provided
`eventsView()`	Interface	Implementation	Tries (and fails) to emit logs in a view context
`customRevert(uint64 number)`	Interface	Implementation	Throws a custom error
`legacyError()`	Interface	Implementation	Throws a hardcoded error

Event	Solidity interface	Go implementation	Description
`Basic`	Interface	Implementation	Emitted in `Events` for testing
`Mixed`	Interface	Implementation	Emitted in `Events` for testing
`Store`	Interface	Implementation	Never emitted (used for testing log sizes)

ArbFunctionTable

ArbFunctionTable (Interface | Implementation) provides aggregators the ability to manage function tables, to enable one form of transaction compression. The Nitro aggregator implementation does not use these, so these methods have been stubbed and their effects disabled. They are kept for backwards compatibility.

Method	Solidity interface	Go implementation	Description
`upload(bytes calldata buf)`	Interface	Implementation	Upload does nothing
`size(address addr)`	Interface	Implementation	Size returns the empty table's size, which is 0
`get(address addr, uint256 index)`	Interface	Implementation	Get reverts since the table is empty

ArbGasInfo

ArbGasInfo (Interface | Implementation) provides insight into the cost of using the chain. These methods have been adjusted to account for Nitro's heavy use of calldata compression. Of note to end-users, we no longer make a distinction between non-zero and zero-valued calldata bytes.

Method	Solidity interface	Go implementation	Description
`getPricesInWeiWithAggregator(address aggregator)`	Interface	Implementation	GetPricesInWeiWithAggregator gets prices in wei when using the provided aggregator
`getPricesInWei()`	Interface	Implementation	GetPricesInWei gets prices in wei when using the caller's preferred aggregator
`getPricesInArbGasWithAggregator(address aggregator)`	Interface	Implementation	GetPricesInArbGasWithAggregator gets prices in ArbGas when using the provided aggregator
`getPricesInArbGas()`	Interface	Implementation	GetPricesInArbGas gets prices in ArbGas when using the caller's preferred aggregator
`getGasAccountingParams()`	Interface	Implementation	GetGasAccountingParams gets the rollup's speed limit, pool size, and tx gas limit
`getMinimumGasPrice()`	Interface	Implementation	GetMinimumGasPrice gets the minimum gas price needed for a transaction to succeed
`getL1BaseFeeEstimate()`	Interface	Implementation	GetL1BaseFeeEstimate gets the current estimate of the L1 basefee
`getL1BaseFeeEstimateInertia()`	Interface	Implementation	GetL1BaseFeeEstimateInertia gets how slowly ArbOS updates its estimate of the L1 basefee
`getL1GasPriceEstimate()`	Interface	Implementation	GetL1GasPriceEstimate gets the current estimate of the L1 basefee
`getCurrentTxL1GasFees()`	Interface	Implementation	GetCurrentTxL1GasFees gets the fee paid to the aggregator for posting this tx
`getGasBacklog()`	Interface	Implementation	GetGasBacklog gets the backlogged amount of gas burnt in excess of the speed limit
`getPricingInertia()`	Interface	Implementation	GetPricingInertia gets the L2 basefee in response to backlogged gas
`getGasBacklogTolerance()`	Interface	Implementation	GetGasBacklogTolerance gets the forgivable amount of backlogged gas ArbOS will ignore when raising the basefee
`getL1PricingSurplus()`	Interface	Implementation	Returns the surplus of funds for L1 batch posting payments (may be negative)
`getPerBatchGasCharge()`	Interface	Implementation	Returns the base charge (in L1 gas) attributed to each data batch in the calldata pricer
`getAmortizedCostCapBips()`	Interface	Implementation	Returns the cost amortization cap in basis points
`getL1FeesAvailable()`	Interface	Implementation	Returns the available funds from L1 fees

ArbInfo

ArbInfo (Interface | Implementation) provides the ability to lookup basic info about accounts and contracts.

Method	Solidity interface	Go implementation	Description
`getBalance(address account)`	Interface	Implementation	GetBalance retrieves an account's balance
`getCode(address account)`	Interface	Implementation	GetCode retrieves a contract's deployed code

ArbosTest

ArbosTest (Interface | Implementation) provides a method of burning arbitrary amounts of gas, which exists for historical reasons. In Classic, ArbosTest had additional methods only the zero address could call. These have been removed since users don't use them and calls to missing methods revert.

Method	Solidity interface	Go implementation	Description
`burnArbGas(uint256 gasAmount)`	Interface	Implementation	BurnArbGas unproductively burns the amount of L2 ArbGas

ArbOwner

ArbOwner (Interface | Implementation) provides owners with tools for managing the rollup. Calls by non-owners will always revert.

Most of Arbitrum Classic's owner methods have been removed since they no longer make sense in Nitro:

What were once chain parameters are now parts of ArbOS's state, and those that remain are set at genesis.
ArbOS upgrades happen with the rest of the system rather than being independent
Exemptions to address aliasing are no longer offered. Exemptions were intended to support backward compatibility for contracts deployed before aliasing was introduced, but no exemptions were ever requested.

Method	Solidity interface	Go implementation	Description
`addChainOwner(address newOwner)`	Interface	Implementation	AddChainOwner adds account as a chain owner
`removeChainOwner(address ownerToRemove)`	Interface	Implementation	RemoveChainOwner removes account from the list of chain owners
`isChainOwner(address addr)`	Interface	Implementation	IsChainOwner checks if the account is a chain owner
`getAllChainOwners()`	Interface	Implementation	GetAllChainOwners retrieves the list of chain owners
`setL1BaseFeeEstimateInertia(uint64 inertia)`	Interface	Implementation	SetL1BaseFeeEstimateInertia sets how slowly ArbOS updates its estimate of the L1 basefee
`setL2BaseFee(uint256 priceInWei)`	Interface	Implementation	SetL2BaseFee sets the L2 gas price directly, bypassing the pool calculus
`setMinimumL2BaseFee(uint256 priceInWei)`	Interface	Implementation	SetMinimumL2BaseFee sets the minimum base fee needed for a transaction to succeed
`setSpeedLimit(uint64 limit)`	Interface	Implementation	SetSpeedLimit sets the computational speed limit for the chain
`setMaxTxGasLimit(uint64 limit)`	Interface	Implementation	SetMaxTxGasLimit sets the maximum size a tx (and block) can be
`setL2GasPricingInertia(uint64 sec)`	Interface	Implementation	SetL2GasPricingInertia sets the L2 gas pricing inertia
`setL2GasBacklogTolerance(uint64 sec)`	Interface	Implementation	SetL2GasBacklogTolerance sets the L2 gas backlog tolerance
`getNetworkFeeAccount()`	Interface	Implementation	GetNetworkFeeAccount gets the network fee collector
`getInfraFeeAccount()`	Interface	Implementation	GetInfraFeeAccount gets the infrastructure fee collector
`setNetworkFeeAccount(address newNetworkFeeAccount)`	Interface	Implementation	SetNetworkFeeAccount sets the network fee collector to the new network fee account
`setInfraFeeAccount(address newInfraFeeAccount)`	Interface	Implementation	SetInfraFeeAccount sets the infra fee collector to the new network fee account
`scheduleArbOSUpgrade(uint64 newVersion, uint64 timestamp)`	Interface	Implementation	ScheduleArbOSUpgrade to the requested version at the requested timestamp
`setL1PricingEquilibrationUnits(uint256 equilibrationUnits)`	Interface	Implementation	Sets equilibration units parameter for L1 price adjustment algorithm
`setL1PricingInertia(uint64 inertia)`	Interface	Implementation	Sets inertia parameter for L1 price adjustment algorithm
`setL1PricingRewardRecipient(address recipient)`	Interface	Implementation	Sets reward recipient address for L1 price adjustment algorithm
`setL1PricingRewardRate(uint64 weiPerUnit)`	Interface	Implementation	Sets reward amount for L1 price adjustment algorithm, in wei per unit
`setL1PricePerUnit(uint256 pricePerUnit)`	Interface	Implementation	Set how much ArbOS charges per L1 gas spent on transaction data.
`setPerBatchGasCharge(int64 cost)`	Interface	Implementation	Sets the base charge (in L1 gas) attributed to each data batch in the calldata pricer
`setAmortizedCostCapBips(uint64 cap)`	Interface	Implementation	Sets the cost amortization cap in basis points
`releaseL1PricerSurplusFunds(uint256 maxWeiToRelease)`	Interface	Implementation	Releases surplus funds from L1PricerFundsPoolAddress for use

Event	Solidity interface	Go implementation	Description
`OwnerActs`	Interface	Implementation	Emitted when a successful call is made to this precompile

ArbOwnerPublic

ArbOwnerPublic (Interface | Implementation) provides non-owners with info about the current chain owners.

Method	Solidity interface	Go implementation	Description
`isChainOwner(address addr)`	Interface	Implementation	IsChainOwner checks if the user is a chain owner
`getAllChainOwners()`	Interface	Implementation	GetAllChainOwners retrieves the list of chain owners
`getNetworkFeeAccount()`	Interface	Implementation	GetNetworkFeeAccount gets the network fee collector
`getInfraFeeAccount()`	Interface	Implementation	GetInfraFeeAccount gets the infrastructure fee collector

ArbRetryableTx

ArbRetryableTx (Interface | Implementation) provides methods for managing retryables. The model has been adjusted for Nitro, most notably in terms of how retry transactions are scheduled. For more information on retryables, please see the retryable documentation.

Method	Solidity interface	Go implementation	Description
`redeem(bytes32 ticketId)`	Interface	Implementation	Redeem schedules an attempt to redeem the retryable, donating all of the call's gas to the redeem attempt
`getLifetime()`	Interface	Implementation	GetLifetime gets the default lifetime period a retryable has at creation
`getTimeout(bytes32 ticketId)`	Interface	Implementation	GetTimeout gets the timestamp for when ticket will expire
`keepalive(bytes32 ticketId)`	Interface	Implementation	Keepalive adds one lifetime period to the ticket's expiry
`getBeneficiary(bytes32 ticketId)`	Interface	Implementation	GetBeneficiary gets the beneficiary of the ticket
`cancel(bytes32 ticketId)`	Interface	Implementation	Cancel the ticket and refund its callvalue to its beneficiary
`getCurrentRedeemer()`	Interface	Implementation	Gets the redeemer of the current retryable redeem attempt
`submitRetryable()`	Interface	Implementation	Do not call. This method represents a retryable submission to aid explorers. Calling it will always revert.

Event	Solidity interface	Go implementation	Description
`TicketCreated`	Interface	Implementation	Emitted when creating a retryable
`LifetimeExtended`	Interface	Implementation	Emitted when extending a retryable's expiry date
`RedeemScheduled`	Interface	Implementation	Emitted when scheduling a retryable
`Canceled`	Interface	Implementation	Emitted when cancelling a retryable
`Redeemed`	Interface	Implementation	DEPRECATED in favour of new `RedeemScheduled` event after the nitro upgrade.

ArbStatistics

ArbStatistics (Interface | Implementation) provides statistics about the chain as of just before the Nitro upgrade. In Arbitrum Classic, this was how a user would get info such as the total number of accounts, but there are better ways to get that info in Nitro.

Method	Solidity interface	Go implementation	Description
`getStats()`	Interface	Implementation	GetStats returns the current block number and some statistics about the rollup's pre-Nitro state

ArbSys

ArbSys (Interface | Implementation) provides system-level functionality for interacting with L1 and understanding the call stack.

Method	Solidity interface	Go implementation	Description
`arbBlockNumber()`	Interface	Implementation	ArbBlockNumber gets the current L2 block number
`arbBlockHash(uint256 arbBlockNum)`	Interface	Implementation	ArbBlockHash gets the L2 block hash, if sufficiently recent
`arbChainID()`	Interface	Implementation	ArbChainID gets the rollup's unique chain identifier
`arbOSVersion()`	Interface	Implementation	ArbOSVersion gets the current ArbOS version
`getStorageGasAvailable()`	Interface	Implementation	GetStorageGasAvailable returns 0 since Nitro has no concept of storage gas
`isTopLevelCall()`	Interface	Implementation	IsTopLevelCall checks if the call is top-level (deprecated)
`mapL1SenderContractAddressToL2Alias(address sender, address unused)`	Interface	Implementation	MapL1SenderContractAddressToL2Alias gets the contract's L2 alias
`wasMyCallersAddressAliased()`	Interface	Implementation	WasMyCallersAddressAliased checks if the caller's caller was aliased
`myCallersAddressWithoutAliasing()`	Interface	Implementation	MyCallersAddressWithoutAliasing gets the caller's caller without any potential aliasing
`withdrawEth(address destination)`	Interface	Implementation	WithdrawEth send paid eth to the destination on L1
`sendTxToL1(address destination, bytes calldata data)`	Interface	Implementation	SendTxToL1 sends a transaction to L1, adding it to the outbox
`sendMerkleTreeState()`	Interface	Implementation	SendMerkleTreeState gets the root, size, and partials of the outbox Merkle tree state (caller must be the 0 address)

Event	Solidity interface	Go implementation	Description
`L2ToL1Tx`	Interface	Implementation	Logs a send transaction from L2 to L1, including data for outbox proving
`L2ToL1Transaction`	Interface	Implementation	DEPRECATED in favour of the new `L2ToL1Tx` event above after the nitro upgrade
`SendMerkleUpdate`	Interface	Implementation	Logs a new merkle branch needed for constructing outbox proofs

General information of precompiles​

Common precompiles​

Other precompiles​

Precompiles reference​

ArbAddressTable​

ArbAggregator​

ArbBLS​

ArbDebug​

ArbFunctionTable​

ArbGasInfo​

ArbInfo​

ArbosTest​

ArbOwner​

ArbOwnerPublic​

ArbRetryableTx​

ArbStatistics​

ArbSys​

General information of precompiles

Common precompiles

Other precompiles

Precompiles reference

ArbAddressTable

ArbAggregator

ArbBLS

ArbDebug

ArbFunctionTable

ArbGasInfo

ArbInfo

ArbosTest

ArbOwner

ArbOwnerPublic

ArbRetryableTx

ArbStatistics

ArbSys