Write chord progressions that hold together musically, without studying theory first.
Choose a key, choose a preset, and it plays immediately with drums, bass and keys behind it.
Then replace chords while the loop runs until it becomes your own.
Free to start.
HOW IT WORKS
1. Choose a key and scale. Only the chords that fit are offered.
2. Choose a preset, or place chords yourself.
3. Press play. A full backing arrangement starts.
4. Replace any chord while it plays, and keep what works.
WHAT YOU GET FREE
- Chord Progression Builder
All 12 keys and every scale. Tensions and slash chords included. Auto-loop, BPM 60-180.
- Chord Detection
Detect chords automatically from an audio file or your own recording. The result stays fully editable, so you can correct whatever the analysis missed and keep working from there.
- 60+ Progression Presets
Pop, Rock, Jazz, Blues, Ballad and more, all included at no cost.
- 8 Groove Styles
Straight, Bounce, Strum, Piano, Shuffle, Pulse, Lo-Fi, and a sustained-chord mode for hearing the harmony. Edit chords in real time while they play.
- Chord Import
Ask any AI chatbot for a song's chords, then paste them in for instant analysis and playback.
- Suggestions
OtoTheory reads the key, the scale, and the chords on either side of the slot you are editing, then proposes chords that fit that exact context. Every suggestion is derived from music theory, so the progression stays coherent whichever one you take.
- Key & Scale Analysis
Auto-detect key and scale, with fit % and degree notation (I, IV, V).
- Fretboard & Keyboard
Guitar, bass and piano views. Chord tones light up in real time as the progression plays. Tap any note to hear it.
- Section Management
Verse, Chorus, Bridge, with repeat counts per section.
- Capo Suggestions
Find easier shapes for acoustic guitar.
- 3 Local Saves
PRO
- Unlimited Saves + iCloud Sync
Keep every idea instead of choosing which three to keep. Sync between iPhone and iPad, and carry it all to a new device.
- 40+ Additional Groove Styles
City Pop, Neo-Soul, Bossa Nova, Lounge Jazz, Amapiano, Trap, Afrobeats, Reggaeton, Salsa, Gospel, Arena Rock and more, plus 6/8 and 12/8 feels.
- MIDI Export
Your arrangement leaves the app as MIDI: a readable chord track, guide tones, a bass track, and section markers. Drums are not flattened into one track. Kick, snare, hi-hat and each percussion instrument arrive on separate tracks, so you can rebalance, swap samples or re-quantise one of them without touching the rest. Opens correctly in Logic Pro, Cubase and Ableton Live.
- Audio Export
Groove-backed audio files for video and social posts.
- No House Banners
The in-app promotional banner is removed.
Pro is available as a monthly or yearly subscription, or as a one-time purchase. Prices are shown in the app in your local currency.
WHO IT IS FOR
Guitarists who want to write songs before studying theory.
Producers who need a fast pre-production sketch before opening a DAW.
Players looking for scale guides to solo over their own changes.
Songwriters hunting for a chord that breaks a dead end.
Musicians who want to know what chords a recording is actually using.
Acoustic players who need a capo position that fits their hands.
FAQ
Q: Do I need to know music theory?
A: No. Choose a key and scale, and only the chords that fit will be offered.
Q: Can it detect chords from a song?
A: Yes. Analyse an audio file or your own recording, then edit the result to correct anything the detection missed.
Q: What does Pro add?
A: Unlimited saves with iCloud sync, 40+ more groove styles, and MIDI and audio export.
Q: Will MIDI open properly in my DAW?
A: Yes. Chords export as a readable chord track with section markers in place, and the drum kit is split into separate tracks by instrument rather than one lane. Tested in Logic Pro, Cubase and Ableton Live.
support@ototheory.com
Privacy: https://ototheory.com/privacy
Terms: https://ototheory.com/terms
Show more
Show less
