Subscriptions are configurable listeners that define what events to watch and how to deliver notifications. They're the foundation of reactivity—create one, and the chain does the rest.
Key Features
Filters: Wildcard (*) for all events, or specify emitters, topics.
On-chain
Costs: Minimum 32 SOM balance to cover handler invocation costs on-chain (validators execute handlers) + small amount of gas (~21K) to create each subscription
Options:
isGuaranteed: Eventual delivery with some block inclusion distance (true/false).
isCoalesced: Batch multiple events into one notification within a block.
Handler Gas params: priorityFeePerGas, maxFeePerGas, gasLimit
Off-chain
Costs: Cost of running the Somnia node or paying an RPC provider
