The main question: is swift mature enough to be used on the server side development?

Swift is a relatively new programming language, and it has been primarily used for developing iOS and macOS applications. However, it is also possible to use Swift for server-side development.

Swift has been gaining popularity as a server-side language in recent years, and many companies have started using it to build their server-side infrastructure. Swift is known for its performance, safety and its ability to handle high-concurrency environments.

Swift’s popularity in the server-side development is also due to its native support for modern features such as asynchronous programming, generics, and optionals, making it a great fit for building high-performance, scalable, and robust server-side applications.

At Wisk Swift does 3 things:

• provides a REST API through Vapor
• connects to the PostgreSQL database
• communicates with the other services through REST API calls

Unit testing/Integration testing

Swift has a great support for unit testing and integration testing. It is possible to write unit tests for the API and integration tests for the API and the database.

• Unit testing is done with the Vapor test framework
• It allows us to test the API using REST API or directly connecting to the database through Services
• Also we can do simple unit testing of the database models

What Swift does not do at Wisk

• Any time we need to use an external service we have a separate service that does that:
  • Examples: Gmail, Couchbase, Firestore, Sendgrid, PDF, XLS generation and so on are implemented in either Kotlin or Php.

Challenges we faced over the years:

• for a long period of time the Swift concurrency model was not mature enough to be used in production, this changed in Swift 5.5 with the introduction of the async/await keywords
• the Swift ecosystem is still not as mature as the Java ecosystem, this means that there are less libraries available for Swift, for this we use services written in Kotlin
• production compilation time: we needed to create a swift build machine to cache previously compiled libraries, to avoid recompiling then every time we build the project
• we wrote our own method to serialize/deserialize to Dictionary and used SwiftyJSON
  • this generated a lot of boilerplate code
  • on the positive this allowed us to have a better control over the JSON encoding/decoding process
  • swift has now a built in JSON encoder/decoder, we are still investigating if we can fully use it for our needs

Our experience with Swift

• It’s a great experience to work with Swift, it’s a very modern language, and it’s very easy to learn
• it’s fast and stable
• it allows us to write code that is easy to read and maintain
• it allows us easy refactoring of the code thanks to its static type system

Seed project

We have created a seed project where we add the new swift feature we use:
Please see it in action in module-swift

Services using Swift at Wisk

• Wisk API
  • contains most of the business logic
• Wisk Queue
  • it’s a wrapper around the PHP Queue Horizon
• Wisk POS Raw (this will be deprecated soon)
  • it used to store the raw data from the POS for specific POS systems: touchbistro, silverware, etc

Moving forward we’ll continue to invest in the Swift Server Side for Wisk:

• Despite considering Kotlin for new services, we’ve observed significant advancements in Swift’s server-side maturity over the last year. Our confidence in Swift’s capabilities for server-side applications has substantially increased.
• Swift has demonstrated robust performance and a growing ecosystem, making it a viable and promising option for Wisk’s backend development.
• Moving forward, we’ll continue to invest in and commit to using Swift for server-side development.

---