A software application is a program you run on your device to do a specific task
A software application (or app) is a set of instructions written in code that tells your computer, phone, or tablet to perform a particular job. When you open Microsoft Word to write a document, launch Spotify to play music, or tap Instagram to scroll photos, you are running a software application. The application sits between you and your device's operating system — it translates what you want to do into commands the hardware can understand.
Applications are different from the operating system itself. Your operating system (Windows, macOS, iOS, Android) is the foundation that manages your device's memory, storage, and hardware. Applications run on top of that foundation. You can have one operating system but hundreds of applications installed on the same device, each one designed to solve a different problem or entertain you in a different way.
Most applications today fall into two categories: those you download and install on your device, and those you access through a web browser. A desktop application like Adobe Photoshop lives on your computer's hard drive. A web application like Google Docs runs in your browser and stores your work on the internet instead. Both are software applications — they just work in different ways.
Key Takeaways
- A software application is a program designed to perform a specific task, from word processing to photo editing to playing games.
- Applications run on top of your operating system and require that operating system to function — an iPhone app will not run on Android.
- Desktop applications install directly on your device and work offline, while web applications run in your browser and need an internet connection.
- Most applications are built for a specific platform and device type, so you need to download the right version for your phone, computer, or tablet.
How applications get onto your device
Desktop applications typically come from an installer file you download from the publisher's website or from a store like the Microsoft Store or Mac App Store. You run the installer, it unpacks the application's files onto your hard drive, and then you can launch it whenever you want. Once installed, the application stays on your device until you uninstall it.
Mobile applications (apps for phones and tablets) come from app stores — the Apple App Store for iPhones and iPads, or Google Play for Android devices. You search for the app you want, tap "Get" or "Install," and the store downloads and installs it automatically. The app then appears on your home screen or in your app drawer, ready to open.
Web applications work differently. You do not install them at all. Instead, you visit a website in your browser — Gmail, Canva, Trello — and the application runs right there in your browser window. The code for the application lives on a company's servers, not on your device. This means you can use the same web application on any device with a browser, whether it is a Windows computer, a Mac, or a phone.
What happens when you open an application
When you click or tap an application to open it, your operating system loads the application's code from storage into your device's memory (RAM). The application then starts running and displays a window or screen where you can interact with it. Everything you see — buttons, text boxes, menus, images — is part of the application's interface, designed by the developers who built it.
As you use the application, it processes your actions. If you type in a text editor, the application captures your keystrokes and displays them on screen. If you click a button, the application runs the code attached to that button. If you save a file, the application writes that data to your device's storage. The application manages all of this behind the scenes so you only see the results.
When you close the application, it stops running and releases the memory it was using. Your device can then use that memory for other tasks. Some applications save your work automatically; others require you to save manually before closing.
The difference between applications and websites
A website is a collection of pages you view in your browser — news articles, product listings, blog posts. A web application is interactive software that runs in your browser and lets you do work or play games. The line between them is blurry, but the key difference is purpose. A news website shows you information. A web application like Google Sheets lets you create and edit spreadsheets, collaborate with others, and save your work to the cloud.
Desktop and mobile applications are faster and more powerful than web applications because they can use your device's hardware directly. A video editing application on your computer can process video much faster than a web-based editor because it has direct access to your graphics card and processor. Web applications are more convenient because you do not have to install anything and you can access them from any device, but they are limited by what a browser can do.
Why applications need updates
Software developers release updates to fix bugs (mistakes in the code), add new features, and patch security vulnerabilities. A bug might cause the application to crash or behave unexpectedly. A security vulnerability is a weakness that hackers could exploit to steal your data or take control of your device. Updates close those holes.
For desktop and mobile applications, you usually see a notification when an update is available, and you can choose to install it now or later. For web applications, updates happen automatically on the company's servers — you do not have to do anything. The next time you open the application, you are using the newest version.
Keeping applications updated is important for security and stability. Developers stop supporting old versions eventually, which means no more bug fixes or security patches. If you use an outdated application for a long time, you become vulnerable to attacks and may experience crashes or compatibility problems.
Free applications versus paid applications
Some applications are free to download and use forever. Others cost money upfront — you pay once and own a license to use it. Still others are free to download but show advertisements, or free to start but charge money for advanced features (called a freemium model).
Free applications make money in different ways. Some display ads while you use them. Some collect and sell information about how you use the application. Some offer a basic version for free and charge for a premium version with more features. Paid applications typically have no ads and no data collection, but you have to pay to use them.
The cost of an application does not always reflect its quality. Many excellent applications are free, and some paid applications are not worth the money. Read reviews and try free versions before paying for something you are not sure about.
What can go wrong with applications
Applications can crash, meaning they stop responding and close unexpectedly. This usually happens because of a bug in the code, a conflict with another application, or insufficient memory on your device. Restarting the application or restarting your device often fixes the problem.
Applications can also become incompatible with your operating system. If your phone updates to a new version of iOS or Android, an older application might stop working. Developers have to update their applications to work with new operating systems, and some developers abandon old applications and never update them.
Security is another risk. If an application has a vulnerability and you do not update it, hackers could exploit that weakness. Always update applications when updates are available, especially applications that handle sensitive information like banking apps or password managers.
Frequently Asked Questions
What is the difference between an app and a program?
The terms are used interchangeably today. "App" is short for application and usually refers to mobile applications, while "program" is an older term that usually refers to desktop software. Both mean the same thing: a piece of software designed to do a specific task.
Can I use the same application on my phone and my computer?
Not always. Most applications are built for a specific platform — an iPhone app will not run on Android, and a Windows program will not run on a Mac. However, many companies offer versions of the same application for different platforms. Microsoft Office, for example, has versions for Windows, Mac, iPhone, and Android. Web applications work on any device with a browser.
Why do I need to update my applications?
Updates fix bugs that cause crashes, add new features, and patch security holes that hackers could exploit. Using outdated applications leaves your device and data vulnerable. Most applications notify you when updates are available, and you can usually install them with one click.
What happens to my data if I uninstall an application?
It depends on where the application stores your data. If the application saves files to your device's storage, uninstalling it may delete those files. If the application saves your data to the cloud (on the company's servers), your data stays there and you can access it again if you reinstall the application. Always check before uninstalling.
Can applications slow down my device?
Yes. Applications running in the background use memory and processing power, which can slow down your device. If you have many applications installed and running at once, your device will feel sluggish. Closing unused applications and uninstalling ones you do not use can help speed things up.