I Built an Offline-First HTTP Request Queue for Angular

GitHub

Have you ever had a user submit a form, lose their internet connection, and watch their request fail?

I wanted to solve this problem in Angular without forcing developers to build their own queue, IndexedDB storage, retry logic, and network synchronization.

So I built ngx-offline-sync — an open-source Angular library for offline-first HTTP request synchronization.

How it works

When the application is online, requests work normally through Angular’s HttpClient.

When the connection is lost:

HTTP Request
     ↓
Offline
     ↓
Queue
     ↓
IndexedDB

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The request is persisted locally instead of simply being lost.

Once the connection comes back:

IndexedDB
    ↓
Sync
    ↓
HTTP Request
    ↓
Completed

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What it currently supports

• Automatic queuing of POST, PUT, PATCH, and DELETE requests
• IndexedDB persistence
• Automatic synchronization after reconnect
• Retry handling
• Request status tracking
• Parallel queue processing with batchSize
• Angular HTTP interceptor integration
• No additional dependencies required

The goal is to keep the API simple — you continue using Angular’s HttpClient as usual.

Example

provideOfflineSync({
  batchSize: 5,
});

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That’s it. The library handles the queue and synchronization infrastructure for you.

The project is still evolving, and I’m working on improving the API, documentation, testing, and network-state handling.

If you’re working with Angular and building applications where network interruptions are a real possibility, I’d love for you to take a look.

GitHub
npm