Zhangixalus dulitensis is among the most beautiful and graceful frogs of Borneo. Its name refers to the type locality of the species: Gunung Dulit, Sarawak.

This is a medium-sized tree frog, with males reaching up to 40 mm snout–vent length and females approximately 50 mm. The body is generally slender. The head bears a sharply pointed snout; in lateral view the snout is slightly angled. The canthus rostralis is present but rounded in profile. All digits terminate in adhesive pads, and fingers and toes are fully webbed. The dorsal skin is smooth. A thin skin fold runs along the outer edges of both the forearm and the foot, and small skin flaps are present at the heels. The pupil is horizontal and elliptical. The tympanum is visible, and only a faint, short supratympanic fold can be discerned.

The dorsal coloration is a luminous jade green, adorned with reddish-brown dots and markings, for example above the eyes and highlighting the canthus rostralis toward the snout tip. The axilla and groin are bluish. A pale line extends from the eye to the tip of the snout. The belly skin is partially translucent, allowing the eggs of gravid females to be visible. The webbing between toes IV and V is red. The iris is dark amber.

Males call from vegetation surrounding ponds, and we encountered individuals perched 1–2 m above the ground. The call is a soft trill. Eggs are deposited in foam nests that are attached to vegetation overhanging suitable ponds. 

Zhangixalus dulitensis is fairly common in primary lowland forest, but it is often difficult to locate because it lives high in the canopy and descends only to breed. Breeding events—sometimes involving large numbers of individuals—appear to be unpredictable. We found tadpoles in partially sun-exposed ponds and puddles with silty bottoms, some of which were ephemeral. The species has pond-type tadpoles that reach up to 34 mm in total length. The tail tapers to a narrowly rounded tip. Tadpoles are ocher or buff brown dorsally, with darker pigmentation along the mid-dorsal region. On one occasion, we observed dozens of tadpoles forming a school that foraged together and moved collectively around the pond.