What is Reactivity?

tldr; Pub/sub, for blockchain dApps regardless of environment including

Reactivity is Somnia's event-driven paradigm for dApps. It pushes notifications—combining emitted events and related blockchain state—to subscribers in real-time, enabling "reactive" logic without polling.

Reactivity is currently only available on TESTNET

Core Concepts

• Events: Triggers from smart contracts (e.g., Transfer, Approval).

• State: View calls for contract data fetched at the event's block height.

• Push Delivery: Chain validators / nodes handle notifications, invoking handlers or WebSocket callbacks directly.

• Subscribers: Off-chain apps (TypeScript) or on-chain contracts (Solidity).

This shifts dApps from reactive querying to proactive responses, like a pub/sub system baked into the blockchain.