RxDB - Local Ionic Storage with Encryption, Compression & Sync

When building Ionic apps, developers face the challenge of choosing a robust Ionic storage mechanism that supports:

• Offline-First usage
• Data Encryption to protect sensitive content
• Compression to reduce storage usage and improve performance
• Seamless Sync with any backend for real-time updates

RxDB (Reactive Database) offers all these features in a single, local-first database solution tailored to Ionic and other hybrid frameworks. Keep reading to learn how RxDB solves the most common storage pitfalls in hybrid app development while providing unmatched flexibility.

Why RxDB for Ionic Storage?

1. Offline-Ready NoSQL Storage

Offline functionality is crucial for modern mobile applications, particularly when devices encounter unreliable or slow networks. RxDB stores all data locally so your Ionic app can run seamlessly without needing a continuous internet connection. When a network is available again, RxDB automatically synchronizes changes with your backend - no extra code required.

2. Powerful Encryption

Securing on-device data is paramount when handling sensitive information. RxDB includes encryption plugins that let you:

• Encrypt data fields at rest with AES
• Invalidate data access by simply withholding the password
• Keep your users' data confidential, even if the device is stolen

This built-in encryption sets RxDB apart from many other Ionic storage options that lack integrated security.

3. Built-In Data Compression

Large or repetitive data can significantly slow down devices with minimal memory. RxDB's key-compression feature decreases document size stored on the device, improving overall performance by:

• Reducing disk usage
• Accelerating queries
• Minimizing network overhead when syncing

4. Real-Time Sync & Conflict Handling

In addition to functioning fully offline, RxDB supports advanced replication options. Your Ionic app can instantly sync updates with any backend (CouchDB, Firestore, GraphQL, or custom REST), maintaining a real-time user experience. Plus, RxDB handles conflicts gracefully - meaning less worry about clashing user edits.

5. Easy to Adopt and Extend

RxDB runs with a NoSQL approach and integrates seamlessly into Ionic Angular or other frameworks you might use with Ionic. You can extend or replace storage backends, add encryption, or build advanced offline-first features with minimal overhead.

Quick Start: Implementing RxDB with Dexie Storage

For a simple proof-of-concept or testing environment in Ionic, you can use Dexie.js as your underlying storage. Later, if you need better native performance, you can switch to the SQLite storage offered by the RxDB Premium plugins.

1. Install RxDB and Dexie-based Storage

npm install rxdb rxjs dexie

2. Initialize the Database

import { createRxDatabase } from 'rxdb/plugins/core';
import { getRxStorageDexie } from 'rxdb/plugins/storage-dexie';

async function initDB() {
  const db = await createRxDatabase({
    name: 'myionicdb',
    storage: getRxStorageDexie(), // Using Dexie for local storage
    multiInstance: false // or true if you plan multi-tab usage
    // Note: If you need encryption, set `password` here
  });

  await db.addCollections({
    notes: {
      schema: {
        title: 'notes schema',
        version: 0,
        type: 'object',
        primaryKey: 'id',
        properties: {
          id: { type: 'string' },
          content: { type: 'string' },
          timestamp: { type: 'number' }
        },
        required: ['id']
      }
    }
  });

  return db;
}

3. Ready to Upgrade Later?

When you need the best performance on mobile devices, purchase the RxDB Premium SQLite Storage and replace getRxStorageDexie() with getRxStorageSQLite() - your app logic remains largely the same. You only have to change the configuration.

Encryption Example

To secure local data, add the crypto-js encryption plugin (free version) or the premium web-crypto plugin. Below is an example using the free crypto-js plugin:

import { wrappedKeyEncryptionCryptoJsStorage } from 'rxdb/plugins/encryption-crypto-js';
import { getRxStorageDexie } from 'rxdb/plugins/storage-dexie';
import { createRxDatabase } from 'rxdb/plugins/core';

async function initEncryptedDB() {
  const encryptedDexieStorage = wrappedKeyEncryptionCryptoJsStorage({
    storage: getRxStorageDexie()
  });

  const db = await createRxDatabase({
    name: 'secureIonicDB',
    storage: encryptedDexieStorage,
    password: 'myS3cretP4ssw0rd'
  });

  await db.addCollections({
    secrets: {
      schema: {
        title: 'secret schema',
        version: 0,
        type: 'object',
        primaryKey: 'id',
        properties: {
          id: { type: 'string' },
          text: { type: 'string' }
        },
        required: ['id'],
        // all fields in this array will be stored encrypted:
        encrypted: ['text']
      }
    }
  });

  return db;
}

With encryption enabled:

• text is automatically encrypted at rest.
• Queries on encrypted fields are not directly possible (since data is encrypted), but once a document is loaded, RxDB decrypts it for normal usage.

Compression Example

To minimize the storage footprint, RxDB offers a key-compression feature. You can enable it in your schema:

await db.addCollections({
  logs: {
    schema: {
      title: 'logs schema',
      version: 0,
      keyCompression: true, // enable compression
      type: 'object',
      primaryKey: 'id',
      properties: {
        id: { type: 'string' },
        message: { type: 'string' },
        createdAt: { type: 'string', format: 'date-time' }
      }
    }
  }
});

With keyCompression: true, RxDB shortens field names internally, significantly reducing document size. This helps both stored data and network transport during replication.

RxDB vs. Other Ionic Storage Options

Ionic Native Storage or Capacitor-based key-value stores may handle small amounts of data but lack advanced features like:

• Complex queries
• Full NoSQL document model
• Offline-first sync
• Encryption & key compression out of the box
• RxDB stands out by delivering all these capabilities in a unified library.

Follow Up

For Ionic storage that supports offline-first operations, built-in encryption, optional data compression, and live syncing with any backend, RxDB provides a powerful solution. Start quickly with Dexie for local development and testing - then scale up to the premium SQLite storage for optimal performance on production mobile devices.

Ready to learn more?

• Explore the RxDB Quickstart Guide
• Check out RxDB Encryption to protect user data
• Learn about SQLite Storage in RxDB Premium for top performance on mobile.
• Join our community on the RxDB Chat

RxDB - The ultimate toolkit for Ionic developers seeking offline-first, secure, and compressed local data, with real-time sync to any server.