Vaultrice JS/TS SDK

A secure, real-time cloud storage SDK with a familiar localStorage-like API — enhanced for cross-device, cross-domain sync, optional end-to-end encryption (E2EE), presence, and optional offline-first usage.

Vaultrice is ideal for state sharing between tabs, browsers, devices, or domains — with built-in real-time updates and optional encryption... without managing custom backend WebSocket infrastructure.

Vaultrice offers a free tier — get started without having to pay!

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Table of contents

1. Install
2. Quick start
3. Feature overview
4. Authentication
5. API overview
6. Presence
7. End-to-end encryption (E2EE)
8. Rate Limiting & Throttling
9. SyncObject (reactive object)
10. Offline-first APIs
11. Durable Object Location Strategy
12. Which API Should I Use?
13. Real-World Examples
14. Related Packages
15. Support

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🔧 Installation

npm install @vaultrice/sdk
# or
yarn add @vaultrice/sdk
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🚀 Quick start

import { NonLocalStorage } from '@vaultrice/sdk'

const nls = new NonLocalStorage({
  projectId: 'your-project-id',
  apiKey: 'your-api-key',
  apiSecret: 'your-api-secret'
}, 'your-object-id') // optional explicit ID

await nls.setItem('key', 'value')
const item = await nls.getItem('key')
console.log(item?.value) // 'value'
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📋 Feature Overview

Feature	Description
localStorage-like API	Familiar setItem, getItem, removeItem, etc.
Cross-tab/browser/device/domain	Seamless state sharing across environments
Real-time sync	WebSocket-based updates, instant across clients
Optional end-to-end encryption	Data encrypted client-side, never readable on the server
Client-Side Throttling	Built-in rate limiting to prevent accidental abuse
TTL support	Auto-expiry per key or object
Event system	Listen to changes, removals, messages
SyncObject API	Reactive object that syncs automatically
Offline-first API	createOfflineNonLocalStorage, createOfflineSyncObject
Custom storage adapters	Use IndexedDB, SQLite, or any custom backend (default: LocalStorage)
Full TypeScript support	Strong typings, interfaces, autocompletion
Works in browsers and Node.js	Cross-platform by design

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🔐 Authentication

The SDK supports three authentication approaches — choose based on your threat model and architecture:

1. apiKey + apiSecret (SDK automatically fetches and refreshes short-lived accessToken)
   • Easiest to use for quick builds and server-side code.
   • If used in clients, combine with origin restrictions or a proxy.
2. accessToken (short-lived token, e.g. ~1 hour) — manual refresh
   • Your backend issues a token and the client receives it.
   • You are responsible for refreshing the token before expiry.
3. getAccessToken (async function that returns a token) — recommended for production
   • The SDK calls the function when it needs a token or when a token is close to expiry.
   • You can optionally provide an initial accessToken together with getAccessToken for immediate use (the SDK will validate & auto-refresh as needed).

Example: token-provider (recommended)

const nls = new NonLocalStorage({
  projectId: 'my-project-id',
  accessToken: 'initial-token-if-available',
  getAccessToken: async () => {
    // call your backend to get a fresh token
    const r = await fetch('/api/vaultrice-token')
    if (!r.ok) throw new Error('token fetch failed')
    const { accessToken } = await r.json()
    return accessToken
  }
})
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Access token expiry hooks (if no getAccessToken defined)

nls.onAccessTokenExpiring(() => {
  // ~2 minutes before expiry - useful to prefetch a token or show UX
  const token = await refreshTokenFromBackend()
  nls.useAccessToken(token)
})
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Server-side: Retrieve an access token on the backend

You can securely mint access tokens on your backend using:

import { retrieveAccessToken } from '@vaultrice/sdk'

const accessToken = await retrieveAccessToken('projectId', 'apiKey', 'apiSecret')
// Optionally pass origin if the api key has origin restriction:
// const accessToken = await retrieveAccessToken('projectId', 'apiKey', 'apiSecret', { origin: 'https://your-app.com' })
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Choosing an approach

Option	Token refresh	Secrets in client?	Example uses
apiKey + apiSecret	Auto	Yes (if in client)	Quick setup, automatic renewal, flexible
Short-lived accessToken	Manual	No	Environments where you avoid long-lived secrets

Note: Both methods are fully supported — it’s up to you to decide which fits your architecture and security model.

Read more about it here.

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📚 API overview

Constructor

new NonLocalStorage(credentials, options?)
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credentials: { projectId, apiKey?, apiSecret?, accessToken?, getAccessToken? } options: { id?, class?, ttl?, passphrase?, getEncryptionHandler?, ... }

Storage API (familiar)

// All write operations accept an optional `options` object:
// options: { ttl?: number, updatedAt?: number }
await nls.setItem('key', value, options?)
const item = await nls.getItem('key') // { value, createdAt, updatedAt, expiresAt, keyVersion? }
await nls.setItems({ key1: { value }, key2: { value, ...options } })
await nls.getItems(['key1','key2'])
await nls.getAllKeys()
await nls.getAllItems()
await nls.removeItem('key')
await nls.removeItems(['k1','k2'])
await nls.clear()

// Atomic numeric ops:
await nls.incrementItem('counter', options?)           // increments by 1 (default)
await nls.incrementItem('counter', 5)        // increments by 5
await nls.decrementItem('counter')           // decrements by 1 (default)
await nls.decrementItem('counter', 2) 

// Collection / object helpers:
await nls.push('my-array', element, options?)          // append element to array (creates array if missing)
await nls.splice('my-array', startIndex, deleteCount, items?, options?) // remove/replace elements (like Array.prototype.splice)
await nls.merge('my-obj', { a: 1 }, options?)          // shallow merge into an existing object (creates object if missing)
await nls.setIn('my-obj', 'user.profile.name', 'Alice', options?) // set deep path inside an object (creates parents as needed)
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Example: splice

// remove 2 elements at index 1 and insert 'x','y'
await nls.setItem('arr', ['a','b','c','d'])
await nls.splice('arr', 1, 2, ['x','y'])
const updated = await nls.getItem('arr') // ['a','x','y','d']
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Atomic Operations

The SDK offers atomic numeric operations for counters and similar use-cases:

• incrementItem(name, amount = 1, options?) — Atomically increments a numeric value on the server and returns the updated item metadata.
• decrementItem(name, amount = 1, options?) — Atomically decrements a numeric value on the server and returns the updated item metadata.

Collection / object helpers

• push(name, element, options?) — Appends element to an array stored at the key. If the key does not exist it will be created as an array.
• merge(name, objectToMerge, options?) — Performs a shallow merge of provided object into the stored object at key. Creates the object if missing.
• setIn(name, path, value, options?) — Sets a nested value inside a stored object using dot-path (or array of keys). Parents are created as needed.

Events & realtime

nls.on('connect', () => {})
nls.on('disconnect', () => {})
nls.on('message', msg => {})
nls.on('setItem', evt => {})                     // all
nls.on('setItem', 'myKey', evt => {})            // key-specific
nls.on('removeItem', evt => {})
nls.on('error', e => {})
nls.off('setItem', handler)
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Send messages

nls.send({ type: 'chat', message: 'hi' })                 // via WebSocket
await nls.send({ type: 'notice' }, { transport: 'http' }) // via HTTP (also reaches sender)
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👥 Presence

await nls.join({ userId: 'u1', name: 'Alice' })  // announces presence
await nls.leave()                                 // leave presence
const conns = await nls.getJoinedConnections()   // get {connectionId, joinedAt, data}
nls.on('presence:join', c => {})                 // listen for joins
nls.on('presence:leave', c => {})                // listen for leaves
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Messages sent through nls.send with transport: 'ws' are broadcast to other connected clients (not echoed to sender). transport: 'http' reaches all clients including sender.

Verifying User Identity

While the main SDK authentication verifies that your client can connect to an object, you might also need to verify that a user within that object is who they say they are. This prevents identity spoofing in multi-user applications like chat rooms.

You can enable this feature in your Class Settings in the Vaultrice dashboard. It works for both the join() and send() methods by passing an optional auth object.

There are three modes available:

1. No Verification (Default): The server accepts all join and send calls without user verification.
2. User ID Signature Verification: Your backend signs a specific user ID from your payload. This is great for guaranteeing a user's identity while keeping the rest of the payload flexible.
3. JWT Consistency Verification: Your backend issues a standard JWT. Vaultrice verifies the token and also ensures that any overlapping data between your payload and the token's claims are consistent. This is the most robust option.

Example: JWT Verification (Mode 2)

// --- On your backend ---
import jwt from 'jsonwebtoken'

const payload = { 
  sub: 'user-123',        // The user's unique ID
  name: 'Alice', 
  role: 'moderator' 
}
const identityToken = jwt.sign(payload, YOUR_PRIVATE_KEY, { algorithm: 'RS256' })
// Send this token to your client

// --- In your Client-Side SDK ---
const auth = { identityToken }

// Authenticate when joining
await nls.join(
  { sub: 'user-123', name: 'Alice', customData: '...' }, // Payload must be consistent with token
  auth
)

// Authenticate when sending a message
await nls.send(
  { sub: 'user-123', name: 'Alice', type: 'chat', text: 'Hello!' }, 
  { auth }
)
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Example: User ID Signature (Mode 3)

// --- On your backend ---
import crypto from 'crypto'

const userId = 'user-123'
const userIdSignature = crypto
  .createHmac('sha256', YOUR_SECRET_KEY)
  .update(userId)
  .digest('hex')
// Send signature to your client

// --- In your Client-Side SDK ---
const auth = { 
  userIdSignature
}

// Authenticate when joining (userId in payload must match auth.userId)
await nls.join(
  { userId: 'user-123', name: 'Alice', role: 'user' },
  auth
)

// Authenticate when sending messages
await nls.send(
  { userId: 'user-123', type: 'chat', message: 'Hello!' },
  { auth }
)
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Note: User ID signature verification will not work with encrypted payloads or non-string payloads.

For a complete deep-dive into the security model and configuration options, see our Security Guide.

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🔐 End-to-end encryption (E2EE)

Enable by passing passphrase or getEncryptionHandler when constructing:

const nls = new NonLocalStorage(credentials, {
  id: 'object-id',
  passphrase: 'super secret'
})

await nls.getEncryptionSettings()   // fetch salt + key version
await nls.setItem('secret', 'value') // automatically encrypted when needed
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• The SDK supports key versioning and lazy decryption of previous keys.
• Use rotateEncryption() to create a new key version.

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⚡ Rate Limiting & Throttling

To ensure stability and prevent accidental abuse, the Vaultrice SDK includes a built-in, configurable client-side throttle manager for all operations (both HTTP requests and WebSocket messages).

By default, the SDK limits operations to 100 per minute. This is designed to be permissive enough for almost all use cases while protecting your application and the backend service.

Custom Configuration

You can customize or disable throttling via the throttling option during initialization.

import { NonLocalStorage } from '@vaultrice/sdk'

const nls = new NonLocalStorage(credentials, {
  id: 'my-object-id',
  throttling: {
    enabled: true,          // Enable or disable throttling
    maxOperations: 200,     // Max operations per window
    windowMs: 30 * 1000,    // Time window in milliseconds (30 seconds)
    operationDelay: 50      // Add a 50ms delay between each operation
  }
})
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Option	Description	Default
enabled	A boolean to enable or disable the throttle.	true
maxOperations	The maximum number of operations allowed within the windowMs.	100
windowMs	The time window in milliseconds to track operations.	60000
operationDelay	An artificial delay (in ms) to enforce between consecutive operations.	0

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🧩 SyncObject (reactive object)

High-level reactive object API that syncs fields automatically across clients with presence and messaging:

import { createSyncObject } from '@vaultrice/sdk'

const doc = await createSyncObject(credentials, 'doc-123')
doc.title = 'Hello'             // auto-sync to other clients
console.log(doc.title)          // for another client
doc.on('setItem', (evt) => {})  // or additionally listen to property changes
await doc.join({ name: 'Bob' }) // presence
await doc.send({ type: 'cursor', x: 10 })
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📴 Offline-First APIs

Vaultrice now supports offline-first storage and sync, making your app resilient to network interruptions.

OfflineNonLocalStorage

A drop-in replacement for NonLocalStorage that works offline and automatically syncs changes when reconnected.

import { createOfflineNonLocalStorage } from '@vaultrice/sdk'

const nls = await createOfflineNonLocalStorage(
  { projectId: 'your-project-id', apiKey: 'your-api-key', apiSecret: 'your-api-secret' },
  { id: 'your-id', ttl: 60000 }
)

await nls.setItem('key', 'value') // Works offline!
const item = await nls.getItem('key')
console.log(item.value) // 'value'
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• Local-first: Reads/writes use local storage when offline.
• Automatic sync: Queues changes and syncs with the server when online.
• Conflict resolution: Last-write-wins by default, customizable.
• Custom storage adapters: Use your own storage backend (IndexedDB, SQLite, etc).

OfflineSyncObject

A reactive object that syncs properties locally and remotely, with offline support.

import { createOfflineSyncObject } from '@vaultrice/sdk'

const obj = await createOfflineSyncObject(
  { projectId: 'your-project-id', apiKey: 'your-api-key', apiSecret: 'your-api-secret' },
  { id: 'your-id', ttl: 60000 }
)

obj.foo = 'bar' // Updates locally and syncs when online
console.log(obj.foo) // 'bar'
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• Proxy-based: Use like a normal JS object.
• Events: Listen for changes, removals, presence, and messages.
• Presence: Track who’s online, join/leave notifications.
• Works offline: Changes are queued and synchronized automatically.

This makes it safe on mobile, airplane mode, or unstable networks.

🛠️ Custom Storage Adapter

You can inject your own storage backend for offline mode (for example, IndexedDB, SQLite, or any custom implementation).

Pass your adapter via the storage option when creating an offline instance:

import { createOfflineNonLocalStorage } from '@vaultrice/sdk'

// Example: a minimal custom adapter
class MyAdapter {
  async get(key) { /* ... */ },
  async set(key, value) { /* ... */ },
  async remove(key) { /* ... */ },
  async getAll() { /* ... */ }
}

const nls = await createOfflineNonLocalStorage(
  { projectId: 'your-project-id', apiKey: 'your-api-key', apiSecret: 'your-api-secret' },
  { id: 'your-id', storage: MyAdapter }
)

// Now all offline reads/writes use your adapter!
await nls.setItem('foo', 'bar')
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Requirements: Your adapter should implement these async methods:

• get(key): Promise<any>
• set(key, value): Promise<void>
• remove(key): Promise<void>
• getAll(): Promise<Record<string, any>>

This works for both createOfflineNonLocalStorage and

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📍 Durable Object Location Strategy

Vaultrice uses Cloudflare Durable Objects. The first successful request for an ID fixes its "home" region:

• All subsequent writes for that ID go to that region.
• Useful for data residency & latency considerations.
• To enforce regions, initialize from the right region first:

const prefsUS = await createSyncObject(credentials, 'prefs-us') // US region
const prefsEU = await createSyncObject(credentials, 'prefs-eu') // EU region
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📦 Which API Should I Use?

Use Case	Recommended API
Simple, key-based storage	NonLocalStorage
Real-time object sync	createSyncObject
Works offline with auto-resync	createOfflineSyncObject or createOfflineNonLocalStorage

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🚀 Real-World Examples

Collaborative Text Editor (Full SyncObject)

interface DocumentState {
  content?: string
  title?: string
  lastModified?: number
  selectedText?: { start: number, end: number }
}

const doc = await createSyncObject<DocumentState>(credentials, 'doc-123')

// Join as a user
await doc.join({ 
  userId: 'user-123', 
  name: 'Alice',
  avatar: 'avatar1.png',
  role: 'editor'
})

// Real-time collaborative editing
doc.on('setItem', 'content', (item) => {
  if (item.value !== editor.getText()) {
    editor.setText(item.value) // Update editor with remote changes
  }
})

// Auto-save on edit
editor.on('text-change', () => {
  doc.content = editor.getText()
  doc.lastModified = Date.now()
})

// Show who's editing
doc.on('presence:join', (conn) => {
  showActiveUser(conn.data)
  showNotification(`${conn.data.name} joined the document`)
})

doc.on('presence:leave', (conn) => {
  hideActiveUser(conn.connectionId)
  showNotification(`${conn.data.name} left the document`)
})

// Real-time cursor sharing
doc.on('message', (msg) => {
  if (msg.type === 'cursor-move') {
    updateCursor(msg.userId, msg.position)
  } else if (msg.type === 'selection') {
    showSelection(msg.userId, msg.range)
  }
})

// Send cursor updates
editor.on('cursor-move', (position) => {
  doc.send({ 
    type: 'cursor-move', 
    userId: 'user-123', 
    position,
    timestamp: Date.now()
  })
})

// Send text selection updates
editor.on('selection-change', (range) => {
  doc.send({ 
    type: 'selection', 
    userId: 'user-123', 
    range,
    timestamp: Date.now()
  })
})

// Show live user count
const updateUserCount = () => {
  userCountElement.textContent = `${doc.joinedConnections.length} users online`
}
doc.on('presence:join', updateUserCount)
doc.on('presence:leave', updateUserCount)
updateUserCount() // Initial count
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Real-Time Gaming with SyncObject

interface GameState {
  players?: { [id: string]: { x: number, y: number, score: number, health: number } }
  gameStatus?: 'waiting' | 'playing' | 'finished'
  currentRound?: number
}

const game = await createSyncObject<GameState>(credentials, 'game-room-456')

// Join as player
await game.join({ 
  playerId: 'player-123', 
  name: 'Alice',
  character: 'warrior',
  level: 15
})

// Initialize game state
if (!game.gameStatus) {
  game.gameStatus = 'waiting'
  game.players = {}
  game.currentRound = 1
}

// Update player position
function movePlayer(x: number, y: number) {
  if (!game.players) game.players = {}
  game.players = {
    ...game.players,
    'player-123': { 
      ...(game.players['player-123'] || { score: 0, health: 100 }),
      x, 
      y 
    }
  }
}

// Listen for game state changes
game.on('setItem', 'players', (item) => {
  updateGameBoard(item.value)
})

game.on('setItem', 'gameStatus', (item) => {
  if (item.value === 'playing') {
    startGameLoop()
  } else if (item.value === 'finished') {
    showGameResults()
  }
})

// Handle player actions via messaging
game.on('message', (msg) => {
  switch (msg.type) {
    case 'attack':
      handleAttack(msg.from, msg.target, msg.damage)
      break
    case 'power-up':
      handlePowerUp(msg.playerId, msg.powerUpType)
      break
    case 'chat':
      showChatMessage(msg.from, msg.message)
      break
  }
})

// Send attack action
function attack(targetPlayerId: string, damage: number) {
  game.send({
    type: 'attack',
    from: 'player-123',
    target: targetPlayerId,
    damage,
    timestamp: Date.now()
  })
}

// Show live player list
game.on('presence:join', (conn) => {
  addPlayerToLobby(conn.data)
})

game.on('presence:leave', (conn) => {
  removePlayerFromLobby(conn.connectionId)
  
  // Remove from game state too
  if (game.players && game.players[conn.data.playerId]) {
    const updatedPlayers = { ...game.players }
    delete updatedPlayers[conn.data.playerId]
    game.players = updatedPlayers
  }
})
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📦 Related Packages

• Vaultrice SDK for React.js
• React.js UI-Components

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🧰 Support

Have questions, ideas or feedback? Open an issue or email us at support@vaultrice.com

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Made with ❤️ for developers who need real-time storage, without the backend hassle.

Try Vaultrice for free!