Warbler is primarily a vibrato effect plugin that offers a wide range of modulation possibilities. It features controls that extend its capabilities to emulate chorus, flange, and delay effects, as well as generating unique hybrid sounds that defy easy classification. This allows users to explore subtle pitch variations or create extreme, dramatic modulations with precision.

The core vibrato effect is powered by an LFO (low frequency oscillator) that can be adjusted from very slow movements to rapid fluctuations up to 5kHz. Users can select from various LFO wave shapes and smoothly transition between them, while additional LFOs modulate both the speed and depth of the vibrato for dynamic and evolving textures. This level of control enables intricate sound design and expressive modulation.

Warbler supports flexible routing options, handling mono, stereo, and multi-channel inputs and outputs. It includes a bias control that shifts the effect from pure vibrato to chorus or flange-like tones, and a feedback control that enhances resonance or introduces echo characteristics. The plugin also offers a spread feature to offset the LFO phase between channels, producing a rich stereo chorus effect when used in compatible hosts.