A guide to hiring a Prism developer
Prism is an open source framework for building apps in C# and .NET. It helps teams keep a large app tidy, so that screens, logic and services are separate and can be tested. It is common in Windows desktop apps built with WPF and also appears in mobile apps built with .NET MAUI or Xamarin.Forms. A Prism developer knows how to use the framework well. Here is what the role includes, how it differs from nearby jobs and how to work well with a remote engineer. It is most useful for founders and managers who run a business app on .NET and need someone who can look after it.
Which Prism this page means
The name is shared by several tools. Prisma is a database toolkit for Node.js and TypeScript. Prism.js highlights code on web pages. Blue Prism is software for automating office tasks. This guide is about the Prism library for .NET apps. If you were looking for one of the others, a Node.js developer is the closer match for Prisma, and the rest need a different kind of specialist.
What Prism gives an app
Prism does not draw screens or store data. It gives your app a shape. It supports the MVVM pattern, which keeps the screen separate from the logic behind it. It provides a way to move between screens, to open dialogs and to share events. It lets you split a large app into modules, and it works with a container that creates and shares services. When these parts are used with care, new developers learn the app faster and bugs are easier to find.
What a Prism developer is responsible for
The job covers the structure of the app and the features inside it. A Prism developer writes view models and services, builds screens in XAML, sets up navigation and modules, and writes tests. They also keep the app up to date with new .NET versions, fix memory and speed problems and document the way the app is organized so the next person can work on it.
How a Prism developer differs from other roles
A Xamarin developer focuses on mobile apps in C# and may or may not use Prism. A software developer is a general role that can include .NET work. A software engineer may design whole systems, from the database to the screen. Use the Prism page when your app already uses Prism, or when you want its structure for a large business app.
When a Prism developer makes sense
- Your WPF or mobile app uses Prism and the original developers have left.
- Your app has grown and the code is hard to change without breaking something.
- You plan to move from older .NET Framework or Xamarin.Forms to current .NET or .NET MAUI.
- You want a large app divided into modules that several people can build.
- You need more unit tests around the logic of your screens.
If your app is small, a general .NET developer may be enough. If you are building a site rather than an app, a web developer is a better fit.
Reading a Prism developer’s background
Ask about the biggest app they worked on and what their part was. Good answers describe the size of the team, the number of modules and a problem they solved. Be careful with a background that only lists framework names. A person can follow a tutorial for Prism without ever having handled navigation between many screens, a memory leak or an upgrade of an old app.
Interview questions to try
- How do you decide what belongs in a view model and what belongs in a service?
- How would you divide a large app into modules?
- What causes memory leaks in XAML apps with events, and how do you prevent them?
- How would you move a Xamarin.Forms app to .NET MAUI?
- How do you test navigation?
Listen for a clear order of steps and for examples from real projects. Doubt anyone who answers with a class name and no reasoning.
Try a paid mini project
Give each finalist a small task from your own code. Useful examples are a review of one module with a list of risks, a fix for a known memory problem, or a short plan for your upgrade path. Pay for the time. Look at how clear the thinking is, how small and safe the steps are and how the person explains choices to a colleague who does not write code.
Match the person to your app
An older desktop app with little documentation needs a patient engineer who enjoys reading other people’s code. A mobile app that is changing platform needs someone who has done a migration before. A new app needs a person who will keep the structure simple. Job titles vary, so ask which parts of past apps each candidate designed or only used.
Agree access and routine
Set the weekly hours at the start and review them every quarter. Give your developer their own logins to the code, the build server and the app store or deployment accounts, and keep ownership of every account in your company name. Ask for work in small pull requests with a short note on each. Remove access when the work ends.
Working with your team
Tell your team early what the Prism developer will look after. Share known problems, old shortcuts and the screens that people avoid touching. A short weekly call and a shared list of tasks keep everyone aligned. Ask for a simple diagram of the modules and how they connect, and keep it where the whole team can find it.
Mistakes to avoid
- Putting business rules in the screen code, which makes them hard to test.
- Creating many modules before there is a reason to split the app.
- Upgrading all at once instead of one module at a time.
- Giving a contractor the only login to your build or store accounts.
Want to look at one area in more detail? See our Xamarin developers for mobile apps in C#, or our software engineers for wider system design.