Realtime Overview

Live subscriptions and optimistic mutations via Zero

The SDK includes a realtime layer powered by Zero, a local-first sync engine. Use it when you need live-updating data or instant optimistic writes.

import { setup, realtime } from '@start-chat/sdk'
import { channelMessages } from '@start-chat/sdk/queries'

await setup({ apiKey: 'sk_live_your_api_key' })

const sub = realtime.subscribe(
  channelMessages,
  { serverId: 'srv_...', channelId: 'ch_...' },
  (messages) => {
    console.info('Messages:', messages.length)
  },
)

API surface

11 subscriptions and 20 optimistic mutations — same queries and mutations as the REST API, but with instant local updates and offline support.

One-shot reads

Use run() for a single read through the realtime layer. This waits for the server to confirm the data is complete, then returns.

import { setup, run } from '@start-chat/sdk'
import { serverMembers } from '@start-chat/sdk/queries'

await setup({ apiKey: 'sk_live_your_api_key' })

const members = await run(serverMembers, { serverId: 'srv_...' }, 'complete')

Value	Behavior
`'complete'`	Wait until server confirms all data is synced
`'lazy'`	Resolve with whatever data is locally available

When to use which

Approach	Latency	Offline	Use case
`query.*`	Server round-trip	No	Scripts, server-side, one-shot reads
`mutate.*`	Server round-trip	No	Scripts, server-side, confirmed writes
`realtime.subscribe`	Instant (local)	Yes	Live UI, dashboards, bots with presence
`realtime.mutate.*`	Instant (local)	Yes	Interactive apps, chat UIs
`run()`	Server-confirmed	No	One-shot reads that need freshness guarantee

Patterns

Queries