Sunsine Audio is a small effects and sound design outfit run by Fletcher Kaufman, releasing handmade guitar pedals, Eurorack modules, and software preset banks for iOS synthesizers. The operation sits at the experimental end of the boutique pedal world, with each unit assembled by hand in low quantities.

The brand is best known for the Harmonic Decoder, a phase-locked-loop pedal that behaves like a single-oscillator analog synth tracking the player's input — covering territory from 8-bit glitch and pitch shifting to filter and fuzz tones — and the Vanishing Point fuzz, a compact three-knob box voiced for guitar but often used on bass, synths, and drum signals. Premier Guitar has reviewed work from the brand, and units have circulated through Reverb and Guitar Center listings.

Outside of hardware, Sunsine Audio has built a parallel catalog of preset and soundset packs for iOS instruments including Yonac's Magellan, Moog's Animoog, Waldorf's NAVE, and the Arctic Keys and Prophet-08 apps, positioning the project as much a sound-design studio as a pedal company.

Sunsine Audio has 3 products cataloged on Equipboard, including Guitar Synth Pedals and Modular Synthesizers. Their gear is featured by 2 artists, with the strongest followings in Electronic, Rock, and Jazz. Notable users include Merzbow and Toshiji Mikawa.