Application Programming Interface (API) development is growing in popularity and because of that, it is more important than ever to develop high-quality APIs. There is often a rush to build APIs and therefore their design can suffer consequently. This may have a negative impact on the companies and consequently a poor user experience. Different “first” methodologies decide the approach when it comes to developing APIs. The purpose of this study is to investigate what API-first methodology has for value when developing APIs. This is done by developing two APIs where one is using the API-first approach while the other makes use of Code-first. This thesis is using a qualitative method of semi-structured interviews to collect data, with the focus to highlight the differences between the APIs developed. Specifically, the differences in test efficiency, user experience, and API correctness.  The conclusion from the study points out that by using API-first the user experience gets a higher quality in terms of documentation, test efficiency, and accuracy in the business requirements. Also, it provides a suggestion for when and why a company should use it. The findings suggest that when the project is big and complex, then API-first is a good option to consider. The continuous dialog between developer and client is why it is such an approving method to use. The hope is that the findings of this thesis are an indicator that API-first is a significant method to use and that more companies consider it when developing APIs.

The overall purpose of this project is to create a tool that will be able to generate reports for measurements and calculations performed by the Perception system. At present, this is a manual procedure that is both time-consuming, inefficient, and increases the risk of error. Since Perception is developed in C#, the reporting tool will be developed in ASP.NET Core with C# based on the MVC pattern and all data will be stored in Microsoft's SQL server. Transfer of data between systems will be handled by export files that Perception can generate as well as a self-developed import function in the reporting tool. With a few simple settings and options, the operators will be able to generate reports for the selected project and then copy them to the final report. Initial work with design and usability, based on the existing graphic profile, will result in an application that significantly facilitates the work of producing test reports. To make the design appealing, Bootstrap and self-written CSS will be used and to make the user experience as good as possible, JavaScript and AJAX will be used together with jQuery and thus be able to provide relevant information without the need of page reload. Focus will be placed on validating imported data to ensure that correct information is available and stored in the database. To further help the users, relevant messages will show status both in case of problems but also in case of successful procedures. / Det övergripande syftet, för detta projekt, är att skapa ett verktyg som ska kunna generera rapporter för mätningar och beräkningar utförda i systemet Perception. I dagsläget är detta ett manuellt förfarande som både är tidskrävande och ineffektivt vilket också ger en ökad risk för felkällor. Eftersom Perception är utvecklat i C# kommer rapportverktyget att utvecklas i ASP.NET Core med C# baserat på MVC-mönstret och all data kommer lagras i Microsofts SQL server. Överföringen av data mellan systemen kommer att ske med hjälp av de exportfiler som Perception kan generera samt en egenutvecklad importfunktion i rapportverktyget. Med några enkla inställningar och val ska operatörerna kunna generera rapporter för valt projekt och sedan kunna kopiera dem till slutrapporten. Ett inledande arbete med design och användbarhet, som grundar sig på den befintlig grafisk profilen, ska mynna ut i en applikation som väsentligt underlätta arbetet med att producera testrapporter. För att göra designen tilltalande kommer Bootstrap och egenskriven CSS att användas och för att användarupplevelsen ska bli så bra som möjligt kommer JavaScript samt AJAX att användas tillsammans med jQuery och på så vis kunna ge relevant information utan att sidan behöver uppdateras. Stort fokus kommer att läggas på kontroller av importerad data för att säkerställa att rätt information finns representerat samt sparas till databasen. För att ytterligare underlätta för användarna ska relevanta meddelanden ge status både vid problem men också vid lyckade procedurer.

Relational databases are the most popular databases used by enterprise applications to store persistent data to this day. It gives a lot of flexibility and efficiency. A process called database normalization helps make sure that the database is free from redundancies and update anomalies. In a Database-First approach to software development, the database is designed first, and then an Object-Relational Mapping (ORM) tool is used to generate the programming classes (data layer) to interact with the database. Finally, the business logic code is written to interact with the data layer to persist the business data to the database. However, in modern application development, a process called Code-First approach evolved where the domain classes and the business logic that interacts with the domain classes are written first. Then an Object Relational Mapping (ORM) tool is used to generate the database from the domain classes. In this approach, since database design is not a concern, software programmers may ignore the process of database normalization altogether. To help software programmers in this process, this thesis takes the theory behind the five database normal forms (1NF - 5NF) and proposes Five Class Normal Forms (1CNF - 5CNF) that software programmers may use to normalize their domain classes. This thesis demonstrates that when the Five Class Normal Forms are applied manually to a class by a programmer, the resulting database that is generated from the Code-First approach is also normalized according to the rules of relational theory.