TimeBoost

TimeBoost is Arbitrum’s priority sequencing auction that grants the winner a 200ms express lane advantage over the public mempool. This is a key differentiator for the platform — the agent can bid for express lane access, execute priority trades, and resell unused capacity for profit.

What Is TimeBoost?

TimeBoost is Arbitrum’s answer to MEV. Instead of a first-come-first-served mempool, Arbitrum runs a sealed-bid, second-price auction every 60 seconds. The winner of each round becomes the express lane controller and can submit transactions that get sequenced 200 milliseconds before any public mempool transactions.

60-Second Rounds

Each auction round lasts 60 seconds. Bids must be submitted at least 15 seconds before the round starts.

Sealed-Bid Auction

Bids are private. You pay the second-highest bid, not your own — incentivizing truthful bidding.

200ms Priority

The express lane controller’s transactions are sequenced 200ms ahead of public mempool transactions.

Why It Matters

The 200ms priority window creates a structural advantage for:

DEX arbitrage: capture price discrepancies across Uniswap, Camelot, and other DEXs before other traders
Liquidations: be first to liquidate undercollateralized lending positions on Aave, Radiant, etc.
Backrunning: execute profitable backrun trades on large public mempool transactions
Priority execution: ensure your time-sensitive trades execute before competitors

On Arbitrum, TimeBoost replaces traditional block builder MEV extraction. The revenue goes to the Arbitrum DAO treasury rather than to individual block builders, making it a fairer system overall.

How the Bidder Works

The TimeBoostBidder class manages the full lifecycle of express lane participation.

Bid Loop

When started, the bidder runs a continuous loop:

Detect round transition — polls the auctioneer for the current round number
Estimate round value — calculates expected MEV profit from available strategies
Compare against threshold — skips rounds where expected profit is below minProfitThresholdWei
Fetch auctioneer stats — gets the average winning bid to avoid overbidding
Submit bid — places a bid at 80% of expected profit, capped at 90% of the average winning bid
Wait for result — if won, emits roundWon event; otherwise emits roundLost

Bid Submission

Bids are submitted via JSON-RPC to the autonomous auctioneer:

Method: auctioneer_submitBid
Params: {
  chainId,
  expressLaneController,
  auctionContractAddress,
  round,
  amount
}

The auctioneer only considers the most recent bid per address, so the bidder can update its bid as new information arrives before the auction closes.

Express Lane Transactions

When the bidder wins a round, it can submit transactions via the express lane:

Method: timeboost_sendExpressLaneTransaction
Params: {
  round,
  sequenceNumber,
  transaction,
  auctionContractAddress,
  signature
}

These transactions are sequenced by the Arbitrum sequencer with 200ms priority over the public mempool.

MEV Estimation

The bidder estimates the expected value of each round using a per-strategy model with historical calibration.

Strategy Values

Strategy	Estimated Value	Description
`arb`	~0.002 ETH	Cross-DEX arbitrage opportunities
`liquidation`	~0.005 ETH	Lending protocol liquidation profit
`sandwich`	~0.0015 ETH	Sandwich trading (higher risk)
`backrun`	~0.0008 ETH	Backrunning large transactions
`resale`	~0.003 ETH	Express lane resale revenue

Historical Calibration

The bidder maintains a rolling history of the last 100 round outcomes. This history adjusts the estimation multiplier:

History Signal	Multiplier	Effect
< 5 rounds of data	1.0x	Neutral (no data)
Average profit negative	0.6x	Reduce bid aggressiveness
Average profit > 0.005 ETH	1.2x	Increase bid aggressiveness
Otherwise	1.0x	No adjustment

The bidder also subtracts estimated gas costs (~0.00002 ETH on Arbitrum) from the total expected value before placing a bid.

Call bidder.recordRoundResult(round, profitWei) after each won round to feed the historical calibration system. More data leads to more accurate bid sizing.

Express Lane Resale

A key revenue multiplier: if you win a round but do not need the full 60 seconds of express lane access, you can resell capacity to other searchers.

How Resale Works

Win an express lane round for cost X
Other searchers pay you USDC via x402 micropayments for sub-round access
The resellExpressLane(buyer, pricePaidUsdc) method grants the buyer express lane forwarding rights for the remainder of the round
Multiple resale slots can be active simultaneously within a single round

Revenue Model

The total revenue from a won round can come from three sources:

Direct MEV

Profit from executing priority arbitrage, liquidations, and backruns during the 200ms window.

Resale Revenue

USDC payments from other searchers who buy sub-round express lane access.

Skill Execution

Other agents pay USDC to use the express lane as a paid skill via the MCP server.

TimeBoost Vault Contract

The TimeBoostVault Stylus contract manages the financial infrastructure for bidding and resale:

Bid funding: agents deposit ETH or USDC that the vault uses for auction bids
Resale payments: authorized buyers pay USDC to the vault in exchange for express lane transaction forwarding
Earnings tracking: the contract tracks total_resale_earnings and total_bid_cost for P&L calculation
Owner withdrawal: accumulated profits can be withdrawn by the vault owner

The TimeBoostVault is a Stylus contract written in Rust. It manages the USDC payment flow for resale but does not directly interact with the auctioneer. The off-chain TimeBoostBidder handles bid submission.

Auctioneer Stats

The bidder can query aggregate auction statistics to inform bidding strategy:

const stats = await bidder.refreshAuctioneerStats();
// stats.avgWinningBidWei — average winning bid over recent rounds
// stats.recentRounds    — number of rounds in the sample
// stats.winRate         — our win rate percentage

Stats are cached for 5 minutes to avoid excessive RPC calls.

Risk Factors

TimeBoost bidding involves real financial risk. Consider these factors before enabling automated bidding.

Risk	Description
Overbidding	Bidding more than the MEV you can extract leads to losses
Execution risk	Winning the round does not guarantee profitable MEV execution
Competition	Sophisticated searchers dominate most rounds
Capital lockup	Bid capital is committed for the round duration
Gas costs	Failed strategies still consume gas

Configuration

The TimeBoostBidder accepts these configuration options:

Option	Type	Default	Description
`privateKey`	`Hex`	Required	Signing key for bids and express lane txs
`rpcUrl`	`string`	Arbitrum One public RPC	Arbitrum RPC endpoint
`auctioneerUrl`	`string`	`https://arb1-auctioneer.arbitrum.io/`	TimeBoost auctioneer RPC endpoint
`minProfitThresholdWei`	`bigint`	`0n`	Minimum expected profit to place a bid

Example Usage

Enable TimeBoost bidding with a 0.001 ETH minimum profit threshold

What's the current express lane status?

How many TimeBoost rounds have we won this session?

Resell express lane access at 5 USDC per slot

Getting Started

Agent API

Features

Contracts

Bots

Guides

What Is TimeBoost?

60-Second Rounds

Sealed-Bid Auction

200ms Priority

Why It Matters

How the Bidder Works

Bid Loop

Bid Submission

Express Lane Transactions

MEV Estimation

Strategy Values

Historical Calibration

Express Lane Resale

How Resale Works

Revenue Model

Direct MEV

Resale Revenue

Skill Execution

TimeBoost Vault Contract

Auctioneer Stats

Risk Factors

Configuration

Example Usage

​What Is TimeBoost?

60-Second Rounds

Sealed-Bid Auction

200ms Priority

​Why It Matters

​How the Bidder Works

​Bid Loop

​Bid Submission

​Express Lane Transactions

​MEV Estimation

​Strategy Values

​Historical Calibration

​Express Lane Resale

​How Resale Works

​Revenue Model

Direct MEV

Resale Revenue

Skill Execution

​TimeBoost Vault Contract

​Auctioneer Stats

​Risk Factors

​Configuration

​Example Usage

What Is TimeBoost?

Why It Matters

How the Bidder Works

Bid Loop

Bid Submission

Express Lane Transactions

MEV Estimation

Strategy Values

Historical Calibration

Express Lane Resale

How Resale Works

Revenue Model

TimeBoost Vault Contract

Auctioneer Stats

Risk Factors

Configuration

Example Usage