Violet Sabrewings breed during the rain season, June-September in Mexico (Osés 1999), and May-October or even late November in Costa Rica (Skutch 1967, Stiles and Skutch 1989, Marín 2001); birds collected in El Salvador in July were in breeding condition (Dickey and van Rossem 1938). Marín (2001) suspected that in Costa Rica Violet Sabrewings may have two or more broods, because two or more nests were built very close to one another or on built on top of the old nests.
The nest is "a bulky, well-constructed cup, mainly of green moss, lined with fine fibers and plant down, held together with spider web" (Stiles and Skutch 1989). The mean nest diameter is 40.4 mm (SD 1.19 mm, n=11) and the mean depth is 30.5 mm (SD 4.2 mm; Marín 2001). Nests are placed on horizontal branches 1-6 m above the ground, usually above a ravine or stream (Stiles and Skutch 1989).
The clutch is two; eggs are dull white, unmarked, and subelliptical. Most data on incubation, fledging, and nest success is from Marín (2001). The mass of each eggs represents 13% the mass of the female. Hatching success is 70% (n=10 eggs. The mean incubation period is 20 days (range 19-22 days; n=4 nests). Only the female incubates or cares for the nestlings.
Soon after hatching (with 1-3 hours), nestlings are provisioned with fluid and spiders (Marín 2001). Nestlings fledge after 23 days (range 22-24 days, n=5 nests).