ESI Xkey 25 USB MIDI Controller Keyboard - 25 Velocity-Sensitive Keys, Polyphonic Aftertouch, Brushed Aluminum, Ultra-Slim, Silver

With polyphonic aftertouch and a full-size velocity-sensitive keybed in an ultra-slim brushed aluminum chassis, the ESI Xkey 25 redefines portable MIDI control. Connect via USB to macOS, Windows, iOS, or Android and start performing immediately—no drivers or external power needed.

Overview

The ESI Xkey 25 is a 25-key USB MIDI controller keyboard engineered for musicians who demand professional expression in a travel-ready form. Its full-size keys deliver authentic piano-like response, while polyphonic aftertouch allows per-note pressure control—a rare feature in this class. The brushed aluminum body measures just a few millimeters thin, yet provides a stable, premium feel. USB bus power and class-compliant operation mean you can plug into a laptop, tablet, or even a smartphone and play instantly. The included Xkey Plus app unlocks customization of velocity curves, MIDI channel, and more.

What stands out

• Polyphonic aftertouch for expressive per-note modulation
• Full-size, velocity-sensitive keys in a 25-key layout
• Ultra-slim brushed aluminum chassis—only 16 mm thick
• USB bus-powered and class-compliant; works with macOS, Windows, iOS, Android
• Includes Xkey Plus software for deep customization
• Dedicated octave, pitch bend, modulation, and sustain controls

Technical details

• Number of keys: 25
• Key type: Full-size, velocity-sensitive
• Aftertouch: Polyphonic
• Connectivity: USB (MIDI over USB)
• Power supply: USB bus-powered
• Operating system compatibility: macOS, Windows, iOS, Android
• Controls: Octave Up/Down, Pitch Bend, Modulation, Sustain, Program Change
• Chassis material: Brushed aluminum
• MIDI channels: 16
• Firmware: Upgradable
• Customization software: Xkey Plus App
• Included cables: USB cable
• Colour: Silver

Our verdict

The ESI Xkey 25 delivers studio-grade expression in an impossibly thin package. Polyphonic aftertouch and a premium aluminum build set it apart from typical portable controllers—ideal for producers, live performers, and mobile creators.