Have you ever wondered what happens behind the scenes when you place an order in an online store? How does the system check if the item is still in stock? And why do you receive an order confirmation by email just a few seconds after making a purchase? The answer lies in the backend: it ensures that data is processed correctly, processes are executed, information is stored, and forwarded to the frontend.
What is Backend Development?
Backend development involves processing data on the server side, implementing business logic, and integrating external systems. It ensures that applications work efficiently, data is stored securely, and other systems can be connected easily. It encompasses everything that is executed on the server itself.
External systems (e.g., an ERP or CRM system) are often integrated to automate more complex processes. A practical example: the backend of a customer portal loads a user’s meter reading and customer data from an SAP system after login and passes it on to the web interface.
To ensure that data and states can be stored and retrieved, developers select a suitable database system and create a structure tailored to the use case.
An essential part of backend development is the implementation of interfaces, also known as APIs. These are required to call the logic from the frontend (the user interface) of the program or other processes.
In backend development, complex software architectures are also often designed and implemented to meet the growing demands on software. One example of this is microservice architecture.
Backend developers also develop or integrate the necessary authentication and security measures to prevent unauthorized access to personal data.
How Does the Backend of an Application Work?
The backend of an application often consists of several layers. It structures these and ensures communication between them.
1. Interface
The most obvious part of any backend is the interface (or API). With the help of the API, other applications can communicate with the backend. It acts as a translator, converting data from the user interface into a format the backend can understand. The interface defines which data the backend expects and what it returns. Integrated validation prevents potential security risks, such as the infiltration of malicious code.
2. Business Logic
The core is the business logic, where the already validated data from the interface is processed. Depending on the use case, calculations, transformations, or other types of processing take place here. For example, when a customer places an order, the business logic calculates the total price, verifies stock availability, and sends an order confirmation.
3. Database
The permanent storage of data is often (but not exclusively) handled via databases. These store data entered by users in the interface as well as predefined values for drop-down boxes or background process data.
How Do Frontend and Backend Differ?
Frontend
In frontend development, developers implement user-friendly interfaces. It focuses on what the user sees. Developing user interfaces includes:
Backend
Backend development focuses on implementing business logic—what the application does. This includes:
What Makes a Good Backend?
In general, good backend systems can handle increasing numbers of users and data volumes efficiently. In addition to scalability, forward-thinking planning ensures that the backend is easily extendable to meet future requirements.
Cybersecurity is now an essential component that must be considered during development. Good backends implement modern security measures to prevent unauthorized access. These include authentication methods such as OAuth2 or JWT, encryption techniques for data transmission (TLS/SSL), and regular security updates.
Another important feature is connectivity to the frontend and other processes. Good backends provide interfaces for various use cases to deliver tailored data and functions.
Good backend systems also react reliably to errors. These can include connection interruptions or maintenance work on an external system. A good backend recognizes when a CRM system like Salesforce is unavailable and saves the transaction for later processing.
Why Shouldn’t I Connect the Database/Systems Directly to the Frontend?
The idea may seem appealing when trying to implement a solution quickly and cost-effectively. However, a direct connection comes with serious disadvantages:
Security
For communication between the frontend and third-party or database systems to function, authentication data must be stored in the frontend, and loose firewall permissions must be set up. This increases the risk of attacks, as systems become externally accessible, and authentication credentials can potentially be stolen more easily. Additionally, when connecting to a database or third-party system, unencrypted data may be transmitted over the network if these systems do not support encrypted communication protocols.
Scalability
If certain tasks require more resources, the entire application must be scaled, as business logic, interfaces, and connections are all bundled into a single system. This results in higher resource usage than necessary during scaling.
Separation of Concerns
If everything is implemented within a single application and other systems need to access its processes, complexity increases. Retrofitting interfaces can be cumbersome, and the software as a whole must be further opened for external access.
Which Technologies Are Used for Backend Development?
There are numerous technologies for backend development—too many to list them all here.
Programming Languages
Almost all programming languages can be used for backend development. Some well-known examples include C#, Java, Python, Ruby, PHP, and Rust. The choice of language depends on factors such as:
Databases
The choice of a database system depends on the application’s requirements. Common types include:
Frameworks
The appropriate backend framework depends on the programming language used. Microsoft provides ASP.NET Web API as a backend solution for C#, while Java developers often use Spring Boot.
Cloud
If the application is not to be run on local hardware, it can be hosted by a cloud provider. Cloud computing is typically categorized into Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and serverless architectures. The three largest providers in this segment are Microsoft Azure, Google Cloud Platform, and Amazon Web Services (AWS).
Nowadays, containerization technologies are commonly used in combination with the cloud to ensure a consistent runtime environment. Examples include Docker and containerd.
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