Auction Phases

Information on Block Timing and Kairos Phases

Timing

By default, transactions take 500ms to reach the validator node due to the 'announcement' propagation style, as outlined in the FastLane whitepaper. This means that for the current block time on Polygon PoS of 2 seconds, searchers competing in a PGA for block N and sending their transactions 1.5 second after the start of the previous block will see those transactions included at block N+1.

Default Transaction Inclusion Timing

Through Kairos, FastLane allows searchers to stay competitive in block N after the 1.5 second mark, and up until 100ms before the theoretical sealing time of that block.

Kairos Transaction Inclusion Timing

Auction Phases

Auctions are divided in different phases with their own set of rules, defined as follow:

• Phase A: From [the start of the block] to [500ms before the sealing of that block]:

  • effectiveGasPrice must be higher than the highest for the current auction.

  • totalPrice must be higher than the highest for the current auction.

  • fastBids are propagated (announced) to the network.

• Phase B: From [500ms before the sealing of the block] to [100ms before the sealing of the block]:

  • effectiveGasPrice must be higher than the highest seen in phase A for the current auction.

  • fastBids are not propagated to the network.

• Phase Z: From [100ms before the sealing of the block] to [the start of the next block]:

  • the auction is closed, fastBids will be rejected.

Kairos Phases

Whether in phase A or phase B, fastGasPrice is not allowed to be higher than effectiveGasPrice.

Winning a Kairos auction does not guarantee to be placed at the very top of the block. Searchers still need to have the top gas price to be ranked at the top of the block.

Kairos allow FastLane searchers to keep bidding and increase their transactions' gas price when non-FastLane searchers can't anymore.