der Button
button
A button on a graphical user interface (e.g., on a website or in an app) that triggers an action when clicked.
Klicken Sie auf den „Bestellen“-Button, um den Kauf abzuschließen.
Click the 'Order' button to complete the purchase.

button
Loading your saved state.
button
A button on a graphical user interface (e.g., on a website or in an app) that triggers an action when clicked.
Klicken Sie auf den „Bestellen“-Button, um den Kauf abzuschließen.
Click the 'Order' button to complete the purchase.

'Button' is an English loanword (Anglicism). Its pronunciation is therefore based on English. In German, the word is masculine: 'der Button' (the button).
Der Button leuchtete grün, nachdem die Datenübertragung erfolgreich war.
The button lit up green after the data transfer was successful.
In German, 'der Button' refers only to a button on a screen or to a badge/pin. A button on clothing (e.g., on a shirt) is always called 'der Knopf' (the button).
An meiner Jacke fehlt ein Knopf.
A button is missing from my jacket.
In a digital context, 'Button' is often combined with verbs like 'klicken' (to click) or 'drücken' (to press). Common examples are the 'Speichern'-Button (Save button), the 'Senden'-Button (Send button), or the 'Abbrechen'-Button (Cancel button).
Um die Änderungen zu übernehmen, müssen Sie auf den „OK“-Button klicken.
To apply the changes, you need to click the 'OK' button.
When a badge/pin is meant, 'Button' is often used with verbs like 'tragen' (to wear), 'anstecken' (to pin on), or 'sammeln' (to collect). It is typically worn on a jacket, T-shirt, or backpack.
Auf dem Festival haben alle Buttons mit dem Logo der Band getragen.
At the festival, everyone wore badges with the band's logo.
button
'Knopf' and 'Button' can both mean something small that you use or see on clothing. 'Knopf' is the normal German word for a part on clothing or for a physical button on a device. 'Button' is used mainly for a button on a screen, for example in an app or on a website. A 'Button' can also be a small pin with a picture or slogan. There is a risk of confusion because the English word 'button' often means 'Knopf'. In German, however, you almost always say 'Knopf' for clothing and often 'Button' for apps.

Auf der Webseite findest du den Button zum Bezahlen unten rechts.
On the website, you can find the button for paying at the bottom right.
An meiner Jacke ist heute Morgen ein Knopf abgegangen.
A button came off my jacket this morning.