The Pfalz D.XII first appeared on the western front in the First World War shortly after the June 1918 fighter trials held at Adlershof, Germany, where a number of aircraft were accepted for production by Idflieg (Inspektion der Fliegertruppen). It was built as a replacement for the outdated Albatros and Pfalz D.III scouts and the outclassed Fokker Dr.I triplane. The Pfalz D.XII was a single-seat, two-bay biplane fighter of all-wood construction with a semi-monocoque plywood fuselage. It carried two forward-firing Maxim machine guns synchronized to fire through the propeller arc. The airplane was powered by a six-cylinder, 180-horsepower, water-cooled, in-line Mercedes D.IIIa engine. It had a top speed of 170 kph (106 mph) and a ceiling of 5,640 m (18,500 ft).
The Pfalz D.XII climbed satisfactorily and its performance in level flight was comparable to that of the Fokker D.VII. Because of its sturdy construction, it could dive faster and steeper than the D.VII, but it could not turn as well and was sluggish in combat. Furthermore, it tended to 'float' when landing, and many accidents occurred because of the weakness of the landing gear. Despite these problems, the Pfalz D.XII performed well enough to relieve the German Air Service of its shortage of competitive fighters late in the war. By the time of the Armistice, nearly 800 aircraft had been delivered to front-line service. After the war a substantial number were turned over to the Allies, perhaps as many as 175. Four of those aircraft survive.