Dart

Since your backend will likely expose its functionality over HTTP, you can definitely use PHP in combination with Dart/Flutter. You can use whatever as your backend.

Since Flutter is backed by Google, you get lots of great functionality out-of-the box if you are using Firebase as your backend though. You can even get very far without writing any backend-code. I would recommend having a look at that as well.

Given Angular is written in TypeScript, C# will feel more familiar to you. Other reasons to choose ASP.NET are that it's one of the fastest frameworks out there for any language, has a lower learning curve compared to Spring Boot, allows you to quickly build JSON Web APIs and uses less memory. Another notable option if you have a lot of TypeScript code you wish to reuse is Nest framework, which is a TypeScript framework that uses the same architecture as Angular but for back end APIs. I would still choose ASP.NET over Nest but it depends on what will give you more benefits.

We are using same stack. In my opinion spring boot and angular is the best match and as spring boot has huge and active community. It will be easier for you to find solutions. moreover here is some stack for both frameworks.

Spring Boot with 41.6K GitHub stars and 26.7K forks on GitHub appears to be more popular than ASP.NET Core with 13.6K GitHub stars and 3.34K GitHub forks.

Firstly, there's nothing wrong with Firebase for scalability, not can I see anything wrong with "cheap" - unless you expect to need the more complex tools that MongoDB offers (such as Map/Reduce, GridFS and such), I don't think you would want to pay more to get the same capabilities. That being said, there are advantages to move to an open-source code base that you have the option of hosting yourself - preventing vendor lock-in is a legitimate requirement.

Now, as for hosting MongoDB: there are a lot of providers that will host MongoDB (or compatible, see AWS DocumentDB) for you - AWS, Linode or Digital Ocean all offer managed database as a service, so you don't have to mess with VMs and installing and maintaining your own instance of the database server - they are often also cheaper than just running a VM. There's no need to co-locate the database near the application - all of those managed MongoDB services offer great connectivity so unless millisecond latency is critical for your application, any will do.

That being said, your best bet for starting to work with MongoDB is probably MongoDB's own Atlas service - it is a managed service provider that allows you to select in which cloud hosting provider to co-locate a managed MongoDB instance - they support AWS, Azure, GCP and others. They always have the latest and greatest MongoDB version (they make it themselves) and they even have a free tier for starting development on the cheap.

First, Blazor Server is NOT a real SEO-capabale server-rendered approach. Its much more complex and in short it holds a copy of the HTML that should be shown in the Browser in memory on the server, all user input is sent to the server via websockets and the resulting diff in the HTML is sent back to the browser via websockets. That is generally not very SEO friendly.

When you need SEO capable real server-side rendering you should use ASP.NET MVC or ASP.NET Razor Pages, as these are real server-side-rendering technologies.

That said, OFirst, Blazor Server is NOT a real SEO-capabale server-rendered approach. Its much more complex and in short it holds a copy of the HTML that should be shown in the Browser in memory on the server, all user input is sent to the server via websockets and the resulting diff in the HTML is sent back to the browser via websockets. That is generally not very SEO friendly.

When you need SEO capable real server-side rendering you should use ASP.NET MVC or ASP.NET Razor Pages, as these are real server-side-rendering technologies.

That said,I think you can also use dart for server-side rendering, so that you don't need to learn a new language and especially a huge new ecosystem that is .NET.

With Blazor, depending on the UI you want to build, html and css may be unavoidable because you might have to use Bootstrap, flexbox, etc to properly position and customize the elements. You may be able to get away with using 3rd party component libraries, e.g. Radzen, Telerik, etc., but again it depends on your app. I haven't had to use Javascript much actually, a couple use cases where I've had to was for file downloads and window events.

I agree with John. For the most part, Flutter has been easier to maintain as time goes on when comparing to react native. And in the landscape, the people at Flutter appears to be very active with the framework, a lot of things cooking. Flutter web is very new, but it'll only get better, more stable.

For the most part, Dart/Flutter is a great choice for cross-platform application development. The platform is developed by Google, and will be around for a long time. Unless you need to do very low level stuff, like bluetooth tethering or 3D drawing, flutter should be able to handle anything you need it to.

Hi, I have 3 years with Flutter and I can see that Flutter with Firebase will be a good choice for you, Just start with Firebase, it's a little bit expensive when you have a lot of users, but there you will have some money to build your own API using any other language, and here I recommend Elixir or Python.

And about what you need to learn: - Dart - Flutter - State management for Flutter - Firebase

Then you can publish your app finally, and I wish you a happy published app :)

I would suggest that you first taste both of these technologies by giving them a day or two, and then choose the one you feel comfortable with. There are basic tutorials available at w3schools, and Tutorialspoint. You can choose by doing some exercises they offer.