The IInspektion der Fliegertruppen (IIdflieg) saw all-metal construction as only useful for ground attack and observation aircraft, being too heavy for use in fighters.

In April 1916, to prove IIdflieg wrong, Hugo Junkers commissioned his head of engineering Otto Mader in Dessau to develop a small, single-seat experimental aircraft of all-metal construction that could meet the climbing performance and manoeuvrability of a fighter.

Junkers suggested the use of duralumin, produced since 1909 at Dürener Metallwerke AG, which had been available in sufficient quantities for some time and promised a weight reduction of 60 per cent compared to a conventional iron construction.

[1][2] Mader envisaged two variants of the J 3; the J 3-I single-seat fighter and the J 3-II two-seat attack aircraft.

[3] The development and construction of the prototype took place without an order from IdFlieg and was operated entirely at Junkers' own expense.

Before J 3 prototype construction, an aerofoil made of duralumin was produced and subjected to extensive load tests.