Expert Sleepers is a UK-based maker of Eurorack modules and audio software founded in 2002 by Andrew Ostler (known as "Os"), a programmer and musician based in Edinburgh. The company began as a software venture, releasing the Crossfade Loop Synth VST in 2002, and later expanded into hardware in 2009 with the Silent Way suite — a set of plug-ins designed to bridge the digital audio workstation and modular synthesizers via DC-coupled audio interfaces.

The brand is best known for its modular interfacing tools and multi-function modules. Flagship hardware includes the ES-8 and ES-9 USB audio interfaces, which route audio and control voltage between a DAW and a Eurorack case, the FH-2 MIDI-to-CV converter, and the Disting series (including the Disting mk4, Disting EX, and Disting NT) — compact, menu-driven modules that pack dozens of algorithms such as oscillators, filters, delays, quantizers, and sample players into a single panel.

Software releases continue to complement the hardware line, including Augustus Loop, Silent Way, and Crossfade Loop Synth as VST, AudioUnit, and AAX plug-ins, along with modules for VCV Rack. The company operates as a one-person outfit and maintains a small Bandcamp label releasing music from artists who work with its tools.

Expert Sleepers has 63 products cataloged on Equipboard, including Modular Synthesizers, MIDI Interfaces, and Sampler Plugins. Their gear is featured by 15 artists, with the strongest followings in Electronic, Rock, and Pop. Notable users include Richard Devine, Celldweller, and Andrew Huang. Expert Sleepers's catalog spans the full price spectrum — from entry-level options to high-end flagships.