Klavis is a Brussels-based brand of Eurorack modular synthesizer modules, operating as a label of Belgian electronics company Diagonal Electronics. The company is run by Eric Lukac-Kuruc and grew out of years of subcontracting work in pro-audio and music electronics before launching its own original designs.

The lineup focuses on feature-dense, compact Eurorack modules at relatively accessible price points. Notable products include Twin Waves MkII, a dual algorithm-based VCO/LFO; Quadigy, a four-channel envelope generator with seven-stage envelopes and presets aimed at live performance; CalTrans, a calibration and V/Oct tracking utility for taming and extending the range of analog VCOs; Grainity, a VCF that brings analog granular synthesis into Eurorack; and Mixwitch, a hybrid mixer/switcher. Other modules in the catalog include Flexshaper, Tweakers, Logica XT, ComPair, Nodrain, Two Bits and Terminal 4.

Klavis modules are positioned as predictable, engineering-driven utilities and sound sources, often combining functions that aren't paired in other modular designs. The brand exhibits at events such as Superbooth and is distributed through specialist Eurorack retailers worldwide.

Klavis has 2 products cataloged on Equipboard, including MIDI Interfaces and Modular Synthesizers.