What is Synthio?

Synthio is a free online piano platform you can use directly in your browser — no downloads, no plugins required. It started as an interactive piano synthesizer and has grown into a full music toolkit for anyone who wants to play, explore songs, and learn piano.

Whether you're a complete beginner or a seasoned player, Synthio gives you everything you need in one place.

What you can do today

• 🎹
  Interactive Piano — Play a fully functional keyboard in your browser. Use your computer keyboard, mouse, touchscreen, or a MIDI controller. Choose from synth, grand piano, Rhodes, Wurlitzer, and organ sounds. Full ADSR envelope, filter, reverb, and pitch bend controls.
• 🎵
  Song Chord Sheets — Browse a growing library of songs with chords placed above the lyrics, just like a real chord sheet. Click any chord to hear it and see which keys to press on the piano. Follow along with auto-scroll while the song plays. Community members can submit and edit chord sheets for any song.

Where we're headed

Synthio is growing into a piano learning platform. The goal is to give anyone — from total beginners to intermediate players — the tools to actually learn to play, not just noodle around.

• 🎓
  Structured Lessons — Step-by-step lessons that take you from your first note to playing real songs.
• 📈
  Progress Tracking — See how far you've come and know exactly what to practice next.
• 🎼
  Learn Songs You Love — The chord sheet library isn't just for reading — it'll become the foundation for guided song practice.

Keyboard Shortcuts — Octave 1

The first octave maps to the middle and top rows of your keyboard.

Keyboard Shortcuts — Octave 2

The second octave continues across the keyboard.

Pitch Bend

Pitch bend slides the pitch of all playing notes up or down by up to ±2 semitones and springs back to centre when released. There are three ways to use it:

• 🎡
  Bend Wheel — the dark vertical strip to the left of the keyboard. Drag or touch it upward to bend pitch up, downward to bend pitch down. Release and it springs back to centre automatically.
• ⌨️
  Arrow Keys — hold ↑ to bend pitch up, hold ↓ to bend pitch down. Release the key to spring back.
• 🎹
  MIDI Pitch Wheel — if a MIDI controller is connected, its hardware pitch wheel is read in real time with full 14-bit resolution.

Controls Explained

• 🎵
  Preset — selects the instrument sound. Synth uses the oscillator engine with full control over all settings. Grand Piano, Rhodes, Wurlitzer, and Organ use real sampled recordings (loaded from the web on first use). When a sampled instrument is selected, Waveform and Detune are disabled as they only apply to the synth engine.
• 🔊
  Volume — master output level. Affects all playing notes instantly.
• 🎛️
  Waveform — (Synth mode only) changes the character of the oscillator. Sine is smooth, Square is buzzy, Sawtooth is bright and rich, Triangle is mellow.
• 🎹
  Octave — shifts all keys up or down an octave. Use the − / + buttons in the controls panel, or press the − / = keys on your keyboard.
• ⚡
  Attack — how long it takes for a note to reach full volume after you press a key.
• 📉
  Decay — how quickly the volume drops after the attack peak.
• 🔉
  Sustain — the volume level held while you keep a key pressed.
• 🌊
  Release — how long the note fades out after you release the key.
• 🎚️
  Cutoff — the lowpass filter frequency. Lower values make the sound warmer and more muffled.
• 📡
  Res — resonance of the filter. Higher values add a sharp peak at the cutoff frequency.
• 🔀
  Detune — (Synth mode only) a slightly detuned second oscillator layered on top, adding thickness and warmth.
• ✂️
  Low Cut — removes low frequencies below the set value. Useful for cleaning up bass rumble.
• 🏛️
  Reverb — adds a room or hall effect. Higher values make the sound feel more spacious.

MIDI Setup

• 💻
  Desktop (Chrome / Edge) — plug in your MIDI controller via USB and click the Connect MIDI button. It is detected automatically.
• 🎡
  Pitch Wheel — the hardware pitch wheel on your MIDI controller works automatically once connected.
• 🎛️
  Knobs (CC 14–17) — if your controller sends CC 14, 15, 16 or 17, these are mapped to Cutoff, Resonance, Detune and Low Cut respectively.
• 🤖
  Android — in Chrome go to chrome://flags, enable the Web MIDI API flag, relaunch, then connect via USB OTG adapter.
• 🍎
  iPhone / iPad — use a Lightning or USB-C to USB adapter. Safari on iOS supports Web MIDI natively.
• 📶
  Bluetooth MIDI — works on iOS with compatible controllers. Android support varies by device.

Mobile Tips

• 🔄
  Rotate your device to landscape for the best experience — the full 25-key keyboard fits on screen.
• 👆
  Tap keys directly to play. Multiple fingers work at the same time (polyphonic). Slide your finger across keys to glide between notes.
• ⚙️
  In landscape mode, tap the Settings button in the top-right of the keyboard panel to adjust all controls.
• ⛶
  Tap the fullscreen button to hide the browser UI. On Android, Add to Home Screen for true fullscreen.

Ready to explore?

Jump into the piano, browse chord sheets, or submit a song.