Third-Party App
A third-party app is a program that doesn't come from the manufacturer of the device or operating system, but from another company. It's the normal case on smartphones – and at the same time the point where questions about privacy, fees, and security most often arise.
On a smartphone, programs run that are called apps. Some of them come directly from the manufacturer of the device: on an iPhone, for example, the camera, the Maps app, or the calendar from Apple. Everything else comes from other companies that have nothing to do with the manufacturer. These are exactly the programs called third-party apps. The name comes from the fact that three parties are involved: you as the user, the manufacturer of the device – and, as the third party, the company that wrote the program. Spotify, WhatsApp, Instagram, or a banking app are typical examples.
Who ultimately has control over your device
A smartphone would be pretty boring without third-party apps. No manufacturer can build a music platform, a social network, and a timetable app all by itself at the same time. The value of a device therefore depends heavily on how many outside programs exist for it. This is called an ecosystem: the more developers participate, the more attractive the platform becomes for buyers.
At the same time, this creates a power imbalance. The manufacturer decides which third-party apps are even allowed into its store, the App Store. It can set rules, reject apps, or remove them later. For payments made within an app, Apple and Google traditionally charge a commission that has long been as high as 30 percent. For small providers, that’s a significant share of their revenue.
That’s why the topic regularly ends up in courts and before regulatory authorities. The EU’s Digital Markets Act, a law against excessive market power held by tech corporations, is now forcing Apple to allow other app stores in Europe as well. Anyone who reads business news will almost always encounter the same question in disputes over third-party apps: Who owns access to the customer?
Permissions and interfaces: the technical framework
A third-party app isn’t allowed to simply do anything on the device. The operating system – that is, the underlying software such as Android or iOS – locks every app into a shielded area. This area is called a sandbox. Within the sandbox, the app can do whatever it wants with its own data. It only reaches the outside world through defined channels.
These channels are called interfaces, or APIs. If an app wants to access the camera, microphone, or location, it has to ask for permission. These are exactly the prompts that appear the first time a program is launched. The manufacturer of the operating system decides which interfaces exist at all. If one is missing, the third-party app cannot offer the corresponding function – even if it would technically be possible.
A common misconception is that third-party apps are automatically unsafe. That’s not really true. It becomes risky mainly when an app is installed outside the official store, or when you grant it permissions it doesn’t actually need for its purpose. A flashlight app that asks for your location is a classic warning sign.
Third-party apps in the age of AI assistants
The term has long since stopped being limited to smartphones. AI chatbots like ChatGPT can also be extended with programs from outside providers. These extensions are often called plug-ins, GPTs, or connectors, but they work on the same principle: an outside developer uses an interface of the platform to offer their own function – such as a travel booking or a spreadsheet analysis.
This means the old questions repeat themselves in a new form. Who reviews these extensions? What data from your chat history does the third-party provider get to see? And who ultimately profits from it? Providers of AI models are currently building their own marketplaces and negotiating revenue-sharing arrangements – quite similar to what Apple and Google did fifteen years ago.
In everyday life, you also encounter the term when logging in. When you sign in somewhere using your Google or Apple account, you’re granting a third-party app access to parts of your profile. In the account settings of major providers, there’s a dedicated list for this. Cleaning it up once a year is one of the simplest security measures there is.