Block Slots and Timing

How Block Builders are assigned to and interact with slots on Signet.

Round Robin Slot Assignment

Block Builders may read from the transactions cache at any time, but the sequencer API, the bundles cache, and the orders cache are private and accessible only during the builder's slot.

Block Builders are assigned slots in a round robin fashion. During a Block Builder's assigned slot, the Block Builder may fetch bundles and orders from the cache, and they may receive signatures from the sequencer API.

Block Builder access to the cache and sequencer API is blocked during slots they aren't assigned to. Requests made outside of the Builder's assigned slot timings will receive a 403 error response.

There is a 2 second buffer at the start and end of each block slot during which API access is also blocked to prevent timing games.

Service	API Access	Time Constraints
Transactions Cache	Public	Always Read or Write
Bundles Cache	Authentication Required	During assigned slot
Orders Cache	Authentication Required	During assigned slot
Sequencer API	Authentication Required	During assigned slot

See the SlotCalculator in signet-sdk for more examples of how to determine slot numbers.