What Is an App?

App is short for application. Merriam-Webster defines it as an application, especially one designed for a mobile device such as a smartphone, and dates the first known use to 1981. Spanish and German use the English word as well.

Three things are often mixed up. A native app is written for one operating system, such as iOS or Android, and installed from its store. A website is a set of pages opened in the browser. A progressive web app (PWA), according to MDN, is built with web technologies but behaves like a native app: it can be installed, work offline and integrate with the device, and like a website it runs on several platforms from a single codebase.

A native app is downloaded from the App Store or Google Play and runs directly on the operating system. Each store has its own search. According to Apple, App Store results depend on text relevance, meaning matches with the app's name, subtitle, keywords and primary category, and on user behavior such as downloads, ratings and reviews. Google Play ranks apps on a combination of ratings, reviews, downloads and other factors.

A web app opens in the browser from a URL, like any other page. To be installable as an app, MDN says it needs a web app manifest, a JSON file that tells the browser how it should appear and behave on the device. Many PWAs also use a service worker to work offline, although according to MDN it is not a requirement for installation.

Apps and websites are found in different ways. A native app is discovered mainly through its store's search, which is what ASO deals with. A website or web app has URLs that search engines can crawl and index like any other page, which is what SEO deals with.

Businesses that have both usually promote the app on the website, and that carries a risk for SEO. Google warns that intrusive prompts that cover the content, including app install prompts, make it hard to understand the page and may lead to poor search performance. It recommends banners that take up only a small part of the screen, such as Apple's Smart App Banners. These open the app if it is already installed and do not reappear once closed.

We checked zds.es on 16 October 2026. The site has no app of its own and links to no app store, declares no web app manifest and registers no service worker on the homepage. The Smart App Banner meta tag is missing too. All it declares is a 192-pixel home screen icon (apple-touch-icon). By MDN's criterion, zds.es is a website, not an installable PWA.

• Check whether the use justifies an app or whether a website is enough, before building one.
• Promote the app on the website with a small banner, not a full-screen prompt.
• Take users from the website to the matching screen in the app, which Smart App Banners allow.
• Choose the name, subtitle and keywords of the store listing with care.
• For a web app, declare a manifest so it can be installed.

• Confusing the website's SEO with the app's ASO, when each is found in a different search.
• Covering the website's content with a full-screen prompt to install the app.
• Launching an app without working on the store listing, which is where people search.
• Repeating words from the app name in the App Store keyword field, which Apple advises against.
• Assuming every web app is a PWA, without a manifest that allows installation.