Building Real-Time Features with FeathersJS

Modern web applications increasingly need real-time capabilities. Users expect to see updates without refreshing the page—new messages appearing in chat, order statuses changing, inventory levels updating as items sell. Building these features from scratch is complex, but FeathersJS makes it remarkably approachable.

What is FeathersJS?

FeathersJS is a lightweight framework for building APIs and real-time applications. It runs on Node.js and provides a clean architecture for creating services that can communicate over REST, WebSockets, or both simultaneously. The same service code handles both traditional HTTP requests and real-time connections.

What sets FeathersJS apart from alternatives like Express or Fastify is its built-in real-time layer. When data changes, connected clients receive updates automatically. You don't need to manually manage WebSocket connections or figure out which clients need which updates—Feathers handles this elegantly.

The Service Architecture

At its core, FeathersJS organises your backend around "services"—modules that handle standard operations: create, find, get, update, patch, and remove. This might seem restrictive, but it covers the vast majority of what applications need to do with data.

A service for managing orders might look something like this conceptually: you create orders, find orders (with filters), get specific orders, update order details, and potentially remove cancelled orders. FeathersJS provides consistent patterns for all of this, plus hooks for adding business logic before or after any operation.

Hooks are where FeathersJS really shines. Need to validate data before creating a record? Add a before hook. Need to send an email after an order is placed? Add an after hook. Need to restrict access based on user roles? Add an authorization hook. This separation keeps your service logic clean while allowing sophisticated behaviour.

Real-Time Without the Complexity

The traditional approach to real-time features involves:

1. Setting up a WebSocket server alongside your REST API
2. Managing connections and disconnections
3. Determining which clients should receive which events
4. Serialising and sending updates
5. Handling reconnection and missed events
6. Keeping REST and WebSocket responses consistent

FeathersJS handles all of this automatically. When you create an order via the REST API, any clients connected via WebSocket and listening to the orders service receive the new order in real-time. The same applies to updates and deletions.

This bidirectional transport is particularly powerful. A mobile app might use REST for occasional requests while a dashboard maintains a persistent WebSocket connection for live updates. Both interact with the same service code.

Practical Use Cases

Here are some real-time features we've built with FeathersJS:

Live Order Tracking

For a service business, we built a system where customers could track their order status in real-time. When staff updated an order—from "confirmed" to "in progress" to "completed"—the customer's browser updated instantly. No refreshing, no polling, no missed updates.

Inventory Synchronisation

An eCommerce client with both online and physical presence needed inventory to stay synchronised. When items sell online, the shop floor system shows updated stock. When items sell in-store, the website updates availability. FeathersJS made this bidirectional sync straightforward.

Collaborative Editing

A project management tool where multiple team members could edit project details simultaneously. Changes from one user appeared on others' screens in real-time, with conflict resolution handled gracefully.

Live Dashboards

Business dashboards showing sales, enquiries, and system status that update continuously. No need to refresh to see the latest figures—they stream in as events occur.

Integration with Frontend Frameworks

FeathersJS provides official client libraries for browser applications. These handle connection management, authentication, and real-time subscriptions cleanly.

When working with SvelteKit, we typically use the Feathers client to establish a connection, then use Svelte's reactive stores to reflect real-time updates in the UI. A change in the database flows through FeathersJS, to the client library, into a Svelte store, and updates the DOM—all automatically.

This architecture means the frontend doesn't need to know whether data came from an initial load, a user action, or a push from another client. It's all just data flowing into reactive stores.

Authentication and Authorisation

Real-time applications have particular security considerations. If everyone receives all updates, you're leaking data. FeathersJS includes a robust authentication system and fine-grained control over which clients receive which events.

Channels let you control real-time distribution. You might have a channel for each user that only receives their orders, a channel for administrators that receives all orders, and a public channel that receives only aggregated, anonymised data. The same service handles all three cases.

Authentication supports local strategies (username/password), OAuth (Google, Facebook, etc.), and JWT tokens. The auth system integrates with hooks, so protecting a service is as simple as adding an authenticate hook.

Scaling Considerations

Single-server deployments are straightforward, but what happens when you need multiple servers? Real-time applications face a challenge: if user A is connected to server 1 and user B is connected to server 2, how does an update from A reach B?

FeathersJS supports various adapters for distributing events across servers. Redis is the most common choice—events publish to Redis, and all servers subscribe, ensuring every connected client receives relevant updates regardless of which server they're connected to.

For most small to medium applications, a single server handles thousands of concurrent WebSocket connections comfortably. You often don't need to worry about scaling until you're genuinely successful.

When FeathersJS Makes Sense

FeathersJS is an excellent choice when:

• Real-time is a core requirement—if users need live updates, FeathersJS handles this elegantly.
• You need both REST and real-time—rather than maintaining two systems, one codebase serves both.
• Rapid development matters—the service/hook architecture provides structure while remaining flexible.
• You're building with JavaScript/TypeScript—FeathersJS is a Node.js framework; if your frontend is also JS, everything stays in one language.

It may not be the best fit for applications that are purely REST-based with no real-time requirements (though it works fine for these), or when you need a non-JavaScript backend.

Getting Started

If you're considering a project that needs real-time features—a booking system, dashboard, chat feature, or live-updating application—we'd be happy to discuss how FeathersJS might fit. We've built a variety of applications on the framework and can advise on whether it's right for your specific requirements.

Get in touch to discuss your project, or explore our FeathersJS development services.