Build Chord Progressions,
Play Along, Learn Along
Import chord progressions of your favorite songs from ChatGPT or Gemini — just copy & paste. Instantly hear them with pro grooves, see Roman numeral analysis, and export as MIDI.
OtoTheory — Use Theory Without Tears
What is OtoTheory?
OtoTheory is a chord progression builder and music theory companion for guitar, bass, keyboard players, and DAW users. Build progressions while listening to backing tracks — swap chords, switch grooves, and hear your ideas come to life in real time. No deep theory knowledge needed.
Import Chord Progressions from AI
Ask ChatGPT or Gemini for any song's chords, then just copy & paste. Instant Roman numeral analysis & backing playback.
DJ-Style Composition
Edit chords while music plays. Never break your creative flow.
15 Groove Patterns
5 categories: Energy, Vibe, Unplugged, Traditional, Synth.
OtoTheory AI
3-layer context analysis suggests chords that fit — sensory, theory, and emotional.
50+ Chord Progression Presets
Canon, Pop, Jazz, Blues, and more. Pick one and start playing.
What You Can Do
Import Chords from AI
Ask ChatGPT or Gemini for any song's chord progression, then just copy & paste into OtoTheory. Instantly see Roman numeral analysis, play with grooves, and export as MIDI. iOS app only.
Play Along, Build Along
Hear your chord progression with full backing tracks — drums, bass, and harmony. Swap chords and switch grooves without stopping playback.
Key & Scale Detection (8 Scales)
Auto-detect key with fit percentage. See diatonic chords and fretboard overlay for guitar, bass, and keyboard.
Split Bar — 2 Chords Per Measure
Place two chords in one bar for more complex progressions like ii-V or the Marusa progression.
Section Management
Organize into Verse, Chorus, Bridge, and more. Customize playback order and export sections as MIDI markers.
MIDI Export — 3 Modes
Export to Logic Pro, Cubase, Ableton, and more. Choose Groove, Groove + Theory, or Chords Only mode.
Free Web Tools
Try OtoTheory in your browser — no download needed.
Chord Progression
Build your song's blueprint with theory-backed insights.
Build progressions with 20 presets and 4 free grooves.
Real-time key & scale detection as you compose.
Playful puzzle-like experience keeps your creative flow going.
Find Chords
Visualize the fretboard — connect theory to your instrument.
See scale tones and chord positions on the fretboard in real-time.
Supports guitar, bass, and keyboard views.
Discover new voicings that break out of your usual patterns.
Resources
Quick reference when you need it.
Diatonic, modes, and cadence explained with clear visuals.
A concise guide for quick recall during composition.
Supporting resource for your creative workflow.
My Sketches
Save your sketches — export to DAW when ready.
Save your chord progressions as sketches (Free: 3 local, Pro: unlimited cloud).
Export as Multi-track MIDI to your DAW for final production.
Your creative ideas, always accessible and ready to evolve.
Unlock the Full Experience on iOS
The iOS app takes everything further — real-time backing tracks, AI-powered chord suggestions, and seamless DAW export.
Free vs Pro
Start free, upgrade when you're ready.
Free
$0
- ✓ AI chord progression import
- ✓ 20 chord progression presets
- ✓ 5 groove patterns
- ✓ 3 local sketch saves
- ✓ Key & scale detection
- ✓ OtoTheory AI
Pro
$2.99/month — 7-day free trial
- ✓ 50+ chord progression presets
- ✓ All 15 groove patterns
- ✓ Unlimited saves + iCloud sync
- ✓ Section management
- ✓ MIDI/audio export — 3 modes
- ✓ No ads
Explore More
Start Building Your Chord Progression
Try the free web tools or download the iOS app for the full experience.