Introduction to Real-time with tRPC
Understand the concepts behind real-time communication and how tRPC extends to handle subscriptions.
Introduction to Real-time with tRPC is a free tRPC End-to-End Type Safe APIs lesson on CoddyKit — lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the tRPC End-to-End Type Safe APIs learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Stay Updated: What is Real-time?
Real-time communication means getting updates instantly, as they happen. Unlike traditional web pages where you refresh to see new content, real-time apps push new information to you immediately.
Traditional vs. Real-time Interactions
Understanding the difference is key:
- Traditional APIs: You send a request, the server sends a response. Each action needs a new request.
- Real-time: Once connected, the server can send updates to you anytime, without you asking again. It's like a continuous conversation.
Where Do We See Real-time?
Real-time communication powers many apps you use daily!
- Chat applications: See messages instantly.
- Live sports scores: Updates as points are scored.
- Stock tickers: Price changes reflected immediately.
- Notifications: Get alerts right when they happen.
The Magic Behind Instant Updates
How do apps get these instant updates?
The most common technology for real-time web communication is WebSockets. Unlike HTTP, WebSockets create a persistent, two-way connection between your browser (client) and the server.
This "open line" allows both sides to send data at any time, enabling instant updates.
Simulating a Live Feed
Imagine receiving data every second. This simple JavaScript code simulates a continuous update stream in your browser console.
Try running it to see how new "data" appears over time without you refreshing!
let updateCount = 0;
const intervalId = setInterval(() => {
updateCount++;
console.log(`Live Update: Data item ${updateCount} received!`);
if (updateCount >= 3) {
clearInterval(intervalId); // Stop after 3 updates
console.log("Stream ended.");
}
}, 1000);Bringing Type Safety to Real-time with tRPC
tRPC is known for its incredible end-to-end type safety for traditional API calls (queries and mutations). But what about real-time?
Good news! tRPC extends its magic to real-time communication through a feature called subscriptions. This allows you to build real-time features with the same type safety and developer experience you love.
What are tRPC Subscriptions?
A tRPC subscription is a special kind of procedure that allows a client to "subscribe" to a stream of data from the server. Once subscribed, the client receives updates whenever the server publishes new data related to that subscription.
Think of it like subscribing to a YouTube channel – you get notified every time a new video (data) is published.
How Subscriptions Work: Client & Server Dance
The basic flow for a tRPC subscription involves:
- Client subscribes: The frontend initiates a connection and requests updates for a specific topic.
- Server publishes: When new data becomes available for that topic, the backend pushes it to all connected clients who subscribed.
- Client receives: The frontend instantly gets the new data and can update the UI.
The Power of Type Safety in Subscriptions
One of the biggest advantages of tRPC subscriptions is maintaining end-to-end type safety.
This means that both the data your server publishes and the data your client expects to receive are strictly typed. You'll catch potential errors at development time, not at runtime, making real-time features much more robust and easier to build.
Test Your Understanding
Which of the following best describes the key difference between a traditional API query and a real-time subscription?
Lesson Summary: Real-time Essentials
In this lesson, we explored the world of real-time communication:
- Real-time provides instant updates, unlike traditional request-response.
- WebSockets are the common tech enabling persistent connections.
- tRPC extends its type-safety benefits to real-time via subscriptions.
- tRPC subscriptions allow clients to receive continuous, type-safe data streams from the server.
Next, we'll dive into setting up WebSockets to power these tRPC subscriptions!
Frequently asked questions
Is the “Introduction to Real-time with tRPC” lesson free?
Yes — the full text of “Introduction to Real-time with tRPC” is free to read here on the web, and the tRPC End-to-End Type Safe APIs course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the tRPC End-to-End Type Safe APIs course, upgrade to CoddyKit PRO.
What will I learn in “Introduction to Real-time with tRPC”?
Understand the concepts behind real-time communication and how tRPC extends to handle subscriptions. You practise tRPC End-to-End Type Safe APIs with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start tRPC End-to-End Type Safe APIs?
No prior experience is required. tRPC End-to-End Type Safe APIs on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Introduction to Real-time with tRPC” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this tRPC End-to-End Type Safe APIs lesson?
Yes. Every tRPC End-to-End Type Safe APIs lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Introduction to Real-time with tRPC
- Setting Up WebSockets for Subscriptions
- Implementing Live Data Subscriptions
- Handling Reconnection and Subscription Cleanup