The decision has been made. Blazor is becoming more and more popular, and it’s ready to shape the future of .NET development.
But with every new framework or technology comes the challenge of knowing where to begin. If you’re just starting out, exploring and experimenting will only get you so far. But when it’s time to get serious and create something production-ready, it’s essential to understand the different architectural choices available.
In this guide, I’ll cover the core decisions you’ll need to make with Blazor, specifically whether to opt for Blazor Server or Blazor WebAssembly (WASM). Both options offer their own unique benefits and potential limitations. For larger, more complex applications, we’ll also explore the possibility of combining the two.
But, first things first, let’s break down what each approach offers and what it means for your development process.
Why should I use Blazor?
Blazor brings .NET development into interactive web applications, offering developers an alternative to traditional JavaScript frameworks. For .NET enthusiasts, this opens a world of possibilities, from single-page applications (SPAs) to complex web apps.
Yet, this promise of versatility also presents a choice. Do you take a server-side approach with Blazor Server. Or, do you make use of your client’s device with Blazor WebAssembly?
And for those who still haven’t met Blazor yet, you can discover more here.
What are the pros and cons of Blazor Server?
Blazor Server is a powerful option, with applications fully hosted on the server. Here’s how it stacks up in terms of performance, security, and ease of management:
Instant load times
Because the app’s runtime and libraries reside on the server, users don’t have to download them onto their devices. This keeps load times snappy, especially when you use prerendering. Blazor Server apps benefit from centralized control, allowing administrators to handle configurations and pre-install necessary components. In short this makes it more flexible and compatible with a wide range of browsers, including older ones.
Familiar development process
If you’ve previously worked on MVC applications or APIs, the Blazor Server model will feel familiar. This will make onboarding developers quicker. Much of the logic and principles carry over, easing the transition into Blazor.
However, like any technology, Blazor Server has its limitations.
Scalability concerns
Every user session in Blazor Server requires a dedicated SignalR connection. This can strain resources during high traffic. For those working in Azure, configurations can handle much of this automatically. Otherwise, managing scaling in other hosting environments may require a little extra effort.
Latency and network dependency
Communication in Blazor Server occurs over an established pipeline, requiring constant connectivity and low latency. Network delays can affect the user experience, and offline support is out of reach—something increasingly expected in web applications.
Blazor WebAssembly, the pros & cons of the client-side alternative
Blazor WebAssembly, or WASM, takes a different Blazor development approach. It shifts the application to run on the user’s device. When you load the first page, the app is downloaded and cached. This means faster interactions without round-trips to the server. Let’s look at the pros and cons of this client-side approach.
Fast, serverless experience
WASM runs directly on the client’s device, which means after the initial load, user interactions are immediate. Hosting the app as a Static Web Application (a Microsoft-recommended choice) can also reduce hosting costs and increase stability.
It comes with offline support
With proper setup, WASM apps offer offline functionality, with components cached for offline access. Although it doesn’t turn the app into a full native application, it gives a similar feel by retaining functionality even when in areas of low connectivity.
Despite its advantages, Blazor WebAssembly comes with its own set of drawbacks.
It raises security concerns
Because the entire app runs on the client’s browser, sensitive information is more exposed than in server-based applications. Encrypting sensitive data helps, but crucial logic should be kept on the server via API calls.
It has longer initial load times
Since the whole app needs to be downloaded first of all, heavier applications may result in longer load times. One solution is to make it essential to keep the app’s payload lean.
Some bonus tips to remember about Blazor WebAssembly
- Managing load: keep file sizes low and optimize for fast loading. Make sure to use Runtime Relinking and Ahead-of-Time (AOT) Compilation where possible.
- Browser-based constraints: remember that sensitive operations should be kept server-side and accessed via APIs.
- State management: the application’s state is managed in the browser. Consider using browser-based storage options for persistence across sessions.
Mixing Blazor Server and WebAssembly
Why choose one when you can potentially have both? Combining Blazor Server and WebAssembly allows you to use the strengths of each while mitigating some of their weaknesses. Here’s what a mixed approach can look like:
You have a more flexible memory allocation. In a hybrid setup, memory-heavy operations can be handled server-side, while lightweight client interactions are managed via WASM. This balances the load between the server and the user’s device, allowing for better performance.
You have the choice of selective state persistence. In a hybrid model, WASM can handle the front-end application state while Blazor Server controls core business logic. This offers better user experience without exposing sensitive data on the client side.
However, there is one major downside to combining both models, and it’s the increased complexity. Configuring communication between the server and client instances, and managing separate memory loads, may require more effort from your developers.
How to Decide Between Blazor Server, WebAssembly, and Hybrid
When you are faced with the choice between Blazor Server, WebAssembly, and a mixed approach, the answer boils down to your project’s unique requirements. Here’s a quick guide to help you weigh up your options:
- Small Projects: for simple, lightweight apps with limited functionality, either Blazor Server or WebAssembly on their own should do. Keep it straightforward, avoid unnecessary complexity, and choose the approach that best aligns with the app’s scale and requirements.
- Scalable Applications: for applications that require high scalability, offline functionality, and a responsive user interface, a mixed approach may be ideal. However, this solution is better suited for complex projects with ample resources to handle the added complexity.
Oh, and more final tip, encapsulate components into libraries wherever possible. This way, if you need to switch approaches in the future, much of your work will remain portable. It’s another bonus of Blazor. This allows you to adjust configurations rather than rebuild from scratch.
As you look to get stuck into your Blazor project consider these three questions first:
1.How will your choice impact scalability and resource management?
Each model places unique demands on memory, latency, and user sessions. Make sure your chosen approach aligns with the intended scale of your application.
- Is offline functionality a must-have?
If yes, Blazor WebAssembly might be your best choice, especially for environments with unstable connectivity. For Blazor Server, offline support remains a bit of a challenge.
- What level of data security does your project require?
While Blazor Server offers controlled environments, WebAssembly demands careful handling of sensitive data to avoid exposure.
By answering these questions, you’ll gain greater clarity on which Blazor approach best suits your project needs. Whether server-side, client-side, or a mix of both, Blazor’s flexibility will help you deliver engaging, high-performance applications across various devices and networks. Happy coding!
