Tanstack DB Skills Tanstack DB

TanStack DB Skills

TanStack DB is the reactive client store for your API. It provides sub-millisecond live queries, instant optimistic updates, and seamless integration with REST APIs and sync engines like ElectricSQL.

Routing Table

Quick Detection

Route to live-queries/ when:

• Building queries with useLiveQuery or createLiveQueryCollection
• Using from, where, select, join, groupBy, orderBy
• Working with aggregations (count, sum, avg, min, max)
• Joining data across multiple collections
• Creating derived/materialized views
• Performance questions about query updates

Route to mutations/ when:

• Using collection.insert(), collection.update(), collection.delete()
• Creating custom actions with createOptimisticAction
• Working with transactions via createTransaction
• Implementing paced mutations (debounce, throttle, queue)
• Handling mutation errors or rollbacks
• Questions about optimistic state lifecycle

Route to collections/ when:

• Setting up a new collection
• Choosing between QueryCollection, ElectricCollection, LocalStorage, etc.
• Configuring sync modes (eager, on-demand, progressive)
• Understanding collection lifecycle
• Loading data from APIs or sync engines

Route to schemas/ when:

• Defining schemas with Zod, Valibot, or other StandardSchema libraries
• Understanding TInput vs TOutput types
• Transforming data (string to Date, etc.)
• Setting default values
• Handling validation errors

Route to electric/ when:

• Setting up ElectricSQL integration
• Working with shapes and real-time sync
• Implementing txid matching for mutations
• Debugging sync issues
• Building an Electric proxy

Core Concepts

import { createCollection, useLiveQuery, eq } from '@tanstack/react-db'
import { queryCollectionOptions } from '@tanstack/query-db-collection'

// 1. Define a collection (data source)
const todoCollection = createCollection(
  queryCollectionOptions({
    queryKey: ['todos'],
    queryFn: async () => fetch('/api/todos').then((r) => r.json()),
    getKey: (item) => item.id,
    onUpdate: async ({ transaction }) => {
      await api.todos.update(
        transaction.mutations[0].original.id,
        transaction.mutations[0].changes,
      )
    },
  }),
)

// 2. Query with live queries (reactive, incremental updates)
function TodoList() {
  const { data: todos } = useLiveQuery((q) =>
    q
      .from({ todo: todoCollection })
      .where(({ todo }) => eq(todo.completed, false))
      .orderBy(({ todo }) => todo.createdAt, 'desc'),
  )

  // 3. Mutate with optimistic updates
  const toggleTodo = (id: string) => {
    todoCollection.update(id, (draft) => {
      draft.completed = !draft.completed
    })
  }

  return (
    <ul>
      {todos?.map((todo) => (
        <li key={todo.id} => toggleTodo(todo.id)}>
          {todo.text}
        </li>
      ))}
    </ul>
  )
}

Data Flow

TanStack DB extends unidirectional data flow beyond the client:

┌─────────────────────────────────────────────────────────────┐
│                     OPTIMISTIC LOOP (instant)               │
│  User Action → Optimistic State → UI Update                 │
└─────────────────────────────────────────────────────────────┘
                              ↓
┌─────────────────────────────────────────────────────────────┐
│                     PERSISTENCE LOOP (async)                │
│  Mutation Handler → Server → Sync Back → Confirmed State    │
└─────────────────────────────────────────────────────────────┘

Package Overview