der Knopfdruck
button press
The action of pressing a button in order to operate a machine or device.
Ein einfacher Knopfdruck genügt, um die Kaffeemaschine zu starten.
A simple button press is enough to start the coffee machine.

button press
Loading your saved state.
button press
The action of pressing a button in order to operate a machine or device.
Ein einfacher Knopfdruck genügt, um die Kaffeemaschine zu starten.
A simple button press is enough to start the coffee machine.

The word is a simple compound of 'der Knopf' (the button) and 'der Druck' (the pressure/press). It literally describes the pressure applied to a button.
Der Alarm wird durch einen festen Knopfdruck ausgelöst.
The alarm is triggered by a firm button press.
The fixed expression 'auf Knopfdruck' (at the push of a button) is always meant figuratively and means 'immediately' or 'automatically'. The literal meaning is usually used without the preposition 'auf' (on/at), for example as the subject of the sentence.
Ein Knopfdruck genügt und die Tür öffnet sich.
One button press is enough and the door opens.
In its literal meaning, 'Knopfdruck' (button press) is often used with the prepositions 'mit' (with) or 'durch' (by/through) to describe the means or cause.
Die Maschine lässt sich mit nur einem Knopfdruck bedienen.
The machine can be operated with just one button press.
The idiom 'auf Knopfdruck' (at the push of a button) is a fixed unit. The preposition 'auf' and the dative are fixed here. The expression describes something that is effortlessly and immediately available.
Er wünschte sich, er könnte Informationen auf Knopfdruck abrufen.
He wished he could retrieve information at the push of a button.
immediately
'sofort' and 'auf Knopfdruck' can both express that something happens very quickly. 'sofort' describes only the timing: something happens without delay. 'auf Knopfdruck' (at the push of a button) is a fixed expression and also emphasizes that something happens automatically, easily, or as if through a technical function. That is why 'auf Knopfdruck' fits especially well with devices, programs, or fast processes. For a normal quick reaction, 'sofort' is more natural.

Die Maschine startet auf Knopfdruck und füllt die Flaschen automatisch.
The machine starts at the push of a button and fills the bottles automatically.
Nach dem Alarm verlassen alle sofort das Gebäude.
After the alarm, everyone leaves the building immediately.