Getting Started with Session Key

@symmio/session-key is the framework-agnostic runtime behind SYMMIO’s popup-free trading. It generates and manages a session key — a locally held EVM keypair the app signs trades with silently — so a trader authorizes their wallet once and then trades with no prompt on the hot path. No React, no wagmi, no DOM globals; the same manager runs in browsers, workers, and Node.

1. Install

pnpm add @symmio/session-key viem

viem is a peer dependency — the manager derives accounts and signs through it.

2. Provide storage

The manager persists the key through a SessionKeyStorage adapter you implement. This is where the key lives between sessions — localStorage, IndexedDB, a Node keystore, whatever fits your app.

import { createSessionKeyManager, type SessionKeyStorage } from "@symmio/session-key";
 
const storage: SessionKeyStorage = createAppStorage(); // you own this adapter
 
const manager = createSessionKeyManager({ storage });

3. Initialize and sign

initialize(owner) loads the owner’s existing key from storage, or generates and persists a new one. After that, every sign runs in the background with no wallet prompt.

const state = await manager.initialize(owner); // { address, ... }
 
const { signature } = await manager.sign("hello");

4. Authorize the key on-chain

A fresh session key can sign, but the protocol won’t honor its signatures until the owner delegates to it once — a single wallet popup via grantDelegation (on the InstantLayer). After that, trades sign silently until the delegation expires or is revoked.

import { grantDelegation } from "@symmio/trading-core";
 
await grantDelegation(config, { sessionKey: state.address });

See How it works for the full delegation flow and key lifecycle.

Next steps

• Overview — the complete manager, key-material, and transfer-payload surface.
• How it works — why session keys exist and the grantDelegation flow end to end.
• Provider integration — wiring the manager into SymmioProvider so SDK writes sign through the session key.