OtoTheory - Chord Progression
Songwriting & Scale Practice
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
New: buy Pro once and own it forever—no subscription. Turn your audio or a mic recording into an editable chord draft. Monthly and Annual plans also available.
OtoTheory is a chord progression builder. Create theory-correct progressions intuitively — no theory knowledge required.
Now with AI import: ask AI for any song's chords, copy & paste. Degree analysis, backing playback, and MIDI export — instantly.
Who Is This For?
Guitarists who want to write songs without theory
Players seeking scale guides for solos
DTM users needing pre-production tools
Acoustic players needing capo suggestions
Songwriters wanting chord substitution ideas
Bassists and keyboardists exploring chord tones
Free — All Creative Tools
▸ AI Chord Import
Ask AI for any song's chords, copy & paste. Instant analysis and playback.
▸ Chord Progression Builder
12-slot grid. Pick a key and scale — only correct chords appear. Tensions and slash chords included. Auto-loop, BPM 60-180.
▸ 15 Groove Patterns
All 15 grooves free. Edit chords in real-time while playing.
▸ 50 Presets
Pop, Jazz, Blues, Rock, Ballad — all 50 presets free.
▸ OtoTheory AI
Bridge, Substitute, Advanced modes. AI-powered suggestions to expand your ideas.
▸ Section Management
Verse, Chorus, Bridge. Set repeat counts per section.
▸ Scale Analysis
Auto-detect key and scale. Fit %, degree notation (I, IV, V).
▸ Fretboard & Keyboard
Guitar, bass, piano views. Chord tones highlight in real-time during playback. Tap to play.
▸ Capo Suggestions & 3 Local Saves
Pro — Unlimited Workflow ($2.99/mo)
▸ MIDI Export
Groove arrangement → MIDI. Chord Track, Guide Tones, Bass Track, section markers. Logic Pro, Cubase, Ableton ready.
▸ Audio Export
Groove-backed AAC files for videos and social media.
▸ Unlimited Export
No limits. *Free: 1/day via ad.
▸ Unlimited Saves + iCloud Sync
Sync iPhone & iPad. Transfers to new devices.
▸ Ad-Free
Why OtoTheory?
No Theory Required: Pick a key, select chords. Done.
Game-Like Editing: Swap chords in real-time while grooves play.
3 Visual Views: Guitar, bass, keyboard — chord tones highlighted during playback.
DAW Ready: MIDI export with groove arrangement. Phone to DAW seamlessly.
Acoustic Friendly: Capo suggestions for comfortable positions.
FAQ
Q: Need music theory?
A: No. Pick a key and scale — correct chords appear automatically.
Q: Free vs Pro?
A: All creative features free (15 grooves, 50 presets, all chords, AI, sections). Pro: unlimited export, unlimited saves + iCloud, ad-free.
Q: MIDI export?
A: Pro exports groove arrangement as MIDI with chord track, guide tones, bass, markers.
hello@ototheory.com
Privacy: https://ototheory.com/privacy
Terms: https://ototheory.com/terms
Build progressions and enjoy songwriting with OtoTheory.
more ■ Ideas for how to end your song
At the end of your progression, OtoTheory now suggests fitting ways to finish — a strong close, a soft landing, or a "keep going" feel. Place the ending you want with a single tap.
■ The voicing you pick is the voicing you hear
The guitar chord shapes you choose in Chord Shapes are now reflected in playback. What you see matches what you hear, so your ideas come out just as you imagined.
■ Improved guitar tone
Re-tuned the sound so the difference is clearly audible on your device.
■ Clearer input tabs
Added icons to the tabs on the chord-building screen.
A one-time "lifetime" purchase is also available alongside the monthly and yearly plans — no subscription required.
Plus other small improvements.
Feedback: support@ototheory.com
3.10.0 17h ago
Playback highlighting is now smoother.
We refined how the chord display follows along when a bar holds two chords, making it easier to follow your progression.
Along with monthly and yearly plans, a one-time lifetime purchase is also available.
Plus other small improvements.
Feedback: support@ototheory.com
3.9.2 Jul 30
We've refined the app experience.
Cleaner labels and smoother interactions make building chord progressions easier than ever.
Along with monthly and yearly plans, a one-time lifetime purchase is also available.
Feedback: support@ototheory.com
3.9.1 Jul 30
A one-time lifetime plan is available—no subscription needed.
Alongside monthly and yearly plans, unlock every Pro feature forever with a single purchase.
Chord detection from your playing or your own songs—all on-device, right on your iPhone.
This update includes small improvements for a smoother, more responsive experience.
Feedback: support@ototheory.com
3.9.0 Jul 29
Own Pro forever — no subscription.
A new Lifetime plan unlocks every Pro feature with a single one-time payment. Perfect if you'd rather not subscribe.
Choose it right alongside the Monthly and Annual plans.
■ New Lifetime (one-time) plan
One payment unlocks all Pro features forever: MIDI / PDF export, automatic chord detection from recordings and imports, all grooves, unlimited saves with iCloud sync, and more. It's not a subscription (no auto-renew), and you can restore it anytime with "Restore Purchases."
Plus small improvements.
Feedback: support@ototheory.com
3.8.0 Jul 22
Detect chords automatically—from your playing or your own songs.
Just play guitar or piano, or import a song, and OtoTheory detects the chord progression, key, and sections—entirely on your iPhone.
Analyze and edit the detected chords, then hear them play with the groove you choose.
This update makes the app launch faster and includes small improvements.
Feedback: support@ototheory.com
3.7.2 Jul 17
Detect chords automatically—from your playing or your own songs.
Just play guitar or piano, or import a song, and OtoTheory detects the chord progression, key, and sections—entirely on your iPhone.
Analyze and edit the detected chords, then hear them play with the groove you choose.
This update unifies the feature naming and includes small improvements.
Feedback: support@ototheory.com
3.7.1 Jul 15
Turn your chord progressions into posts.
Share the progressions you make or import as vertical images and videos—one tap to post. Get your music out to more people.
Preview the result before you share.
■ Share chord progressions to social
Share progressions you built in Create, or chords imported from a song, as vertical social images and videos. Videos can even carry the sound you actually played.
■ Share and Export in one place
Access image and video sharing along with Audio, MIDI, and PDF exports—all from "Share / Export."
Plus small improvements.
Feedback: support@ototheory.com
3.7.0 Jul 14
Turn your playing into chords—instantly.
Just play guitar or piano and record. OtoTheory detects the chords, key, and sections automatically. No audio file needed—capture an idea and analyze it on the spot.
▼ New: Detect chords by recording
・Auto-detect chord progressions and key from your performance
・If the highlight drifts, just tap along with the beat to fix it
・Export your progression as Audio / MIDI / PDF (MIDI & PDF are Pro)
▼ Improvements
・Refreshed Library: clear Recording/Imported badges and a "…" menu to export or rename right from the card
・Home screen layout polish and minor fixes
3.6.0 Jul 11
The Create screen is all new — a lead-sheet style grid that lets you see your whole song and build it section by section.
Sections are now color-coded by role, so you can spot the chorus at a glance.
■ Redesigned Create screen
- A vertical, lead-sheet style grid shows your song structure while you edit
- Input is organized into 4 tabs (Chord / Preset / Ideas / Diatonic); Instrument, AI and Analysis moved to the top
■ Section colors (Create & Play)
- Auto color-coding by section role (Chorus = vermillion, Verse = blue, and more)
- Pick your own color from the rename dialog
■ More improvements
- No more blank pages in PDF export, a loading indicator when opening songs, an iCloud sync button on Home, and small bug fixes
3.5.0 Jul 7
Build chord progressions, play them with pro-quality grooves, and turn ideas into songs.
Import a track and OtoTheory analyzes its key and chords for you.
It's your playful pre-production studio.
■ Improved Pro trial experience
We refined the guidance so you can get the most out of Pro features during your free trial.
Plus small improvements.
Feedback: support@ototheory.com
3.4.0 Jul 1
You can now preview Pro grooves before you subscribe.
If you like them, choose the new yearly plan and save two months.
The basic grooves stay free, just as before.
■ Try grooves before you choose
Tap a Pro groove and hear it play along with your current progression—decide with your ears first.
■ New yearly plan
In addition to monthly, you can now pick a yearly plan that saves you two months.
■ Improved library
Saved sketches and imported songs now show groove name, tempo, and time signature at a glance.
Plus small improvements.
Feedback: support@ototheory.com
3.3.0 Jun 29
Added a guide for first-time users.
Just follow the on-screen prompts to add a classic chord progression and play it back.
Plus small improvements.
Feedback: support@ototheory.com
3.2.0 Jun 27
Import any song and OtoTheory detects its chords, key, and sections automatically. No ear-training needed—start playing the songs you love right away.
■ More time signatures
Ballads in 6/8 or 12/8 and other non-4/4 songs now display and play back in the right meter—just one tap.
■ Analyze songs into chords
Load an audio file to get a chord-progression draft, synced to playback on the fretboard.
■ Now even smoother
Highlights keep up clearly while you adjust tempo or meter during playback. Sending an analyzed song to Create mode is clearer too, plus minor bug fixes.
We also added an annual plan—two months free versus paying monthly.
Feedback: support@ototheory.com
3.1.0 Jun 26
Import any song and OtoTheory detects its chords, key, and sections automatically. No ear-training needed—start playing the songs you love right away.
■ Analyze songs into chords
Load an audio file to get a chord-progression draft, synced to playback on the fretboard.
■ See chord shapes
View how to play each chord along your progression, with a look-ahead to what comes next.
■ Now even smoother
We fixed minor bugs and polished the overall experience.
Feedback: support@ototheory.com
3.0.1 Jun 22
What's new:
- Import your own audio and get an automatic chord draft
- Edit the detected chords right away and finish them your own way
- Change key, transpose, edit sections, and practice along with the original
- See how to play each chord on guitar (fretboard) and keyboard — with now/next as you play along
- Manage your sketches and imported songs together in one Library
3.0.0 Jun 21
Seeing how to play a chord is now even clearer.
For guitar, chord shapes are shown right on the fretboard. Following the CAGED system, you can flip through multiple positions for the same chord.
For keyboard, the chord-tone view has been refined. It shows the bass note for your left hand and the chord tones for your right hand directly on the keys, so you can tell which keys to press at a glance — no sheet music required.
Switching between guitar, bass, and keyboard is clearer too, and chord tones are instantly available on every instrument.
Plus various minor improvements and bug fixes.
Feedback: support@ototheory.com
2.21.0 Jun 17
This update includes bug fixes and improvements to enhance your experience.
2.20.2 Jun 6
■ New Foundations category
Clean, single-instrument backings (piano, guitar, bass and more) in whole-note, quarter, eighth, and sixteenth rhythms. With no extra ornamentation, they're perfect for checking how chords and scales sound, practicing or ear-training, and laying a foundation before you arrange.
■ New Neo-Soul groove
A Wurlitzer electric piano plays rich extended-chord voicings (9ths, 11ths, 13ths) for a smooth, feel-good funk-soul sound. Just lining up chords already sets the mood.
Some of the new grooves are Pro, but you can preview them by watching an ad. For full production in a DAW, Audio / MIDI export is available with Pro. Plus various minor improvements.
Feedback: support@ototheory.com
2.20.1 Jun 4
A new piano-driven, high-speed rock groove, "Piano Rock," is now available.
It blends a piano playing shimmering tension chords, a rich choir, and power-chord guitars into an uplifting, anime-opening / emo-style sound. The piano arrangement is built so the harmony stays clear even at fast tempos: the right hand brings out the tensions while the left hand holds down a low foundation.
Piano Rock is a Pro groove, but you can also preview it by watching an ad. If you want to take it further in a DAW, Audio / MIDI export is available with Pro.
Plus various minor improvements and bug fixes.
Feedback: support@ototheory.com
2.18.0 Jun 1
A new groove "Afrobeats" is now available — the 4th entry in the Loops category.
Afrobeats: a mellow West African Afropop groove featuring muted-guitar 16th-note cutting, a syncopated 3-3-2 kick, call-and-response congas, and a soft electric piano. Recommended BPM 95-110 — a relaxed, danceable groove that's ready to build in seconds.
Afrobeats is a Pro groove, but you can also preview it by watching an ad. If you want to take it further in a DAW, Audio / MIDI export is available with Pro.
Plus various minor improvements and bug fixes.
Feedback: support@ototheory.com
2.17.0 May 31
A new groove "Trap" is now available — the 3rd entry in the Loops category.
Trap: an Atlanta Trap groove featuring a deep 808 sub-bass, dark Kalimba stabs with tense voicings, half-time hand-claps, and shimmering hi-hat rolls. Recommended BPM 130-150 — a heavy, sunken half-time beat that's ready to build in seconds.
Trap is a Pro groove, but you can also preview it by watching an ad. If you want to take it further in a DAW, Audio / MIDI export is available with Pro.
Plus various minor improvements and bug fixes.
Feedback: support@ototheory.com
2.16.0 May 30
A new "Loops" category for loop-based beatmaking is now available — added to both chord progression presets and grooves.
[Presets] 7 loop-oriented presets for hip-hop, Lo-Fi, trap, Drill, Latin House, Phonk, and EDM: Lo-Fi Chill / Neo-Soul Loop / Trap Drop / Drill Dark / Latin House / Phonk Vamp / Trap Melodic. With 4-bar and 2-bar cyclic patterns, you have a quick foundation for track-making.
[Grooves] Two new grooves:
- Amapiano: a South African house style featuring a melodic "Log Drum" bassline, laid-back Rhodes chords, and fast 16th-note shakers. Its 4-bar loop is a perfect foundation for your tracks.
- Lo-Fi: a relaxed Lo-Fi hip-hop groove with warm sub bass and a dusty swing. Start a chill beat right away.
We've also consolidated some existing categories: "Blues" and "R&B / Soul" are now combined as "Blues & R&B", and "Acoustic" and "Ballad" are now combined as "Acoustic". All preset content remains fully available.
We've also improved how presets are inserted into split bars. When you add a preset to a bar split into beats (4 or 2), the chords are now distributed to match that bar's split count.
The 7 presets and the Lo-Fi groove are free. Amapiano is a Pro groove, but you can also preview it by watching an ad. If you want to take it further in a DAW, Audio / MIDI export is available with Pro.
Plus various minor improvements and bug fixes, including display stability.
Feedback: support@ototheory.com
2.15.0 May 28
Two new Pro grooves "Nu-Disco" and "Indie Rock" are now available.
"Nu-Disco" delivers modern 2020s disco-pop. With funky 16th-note guitar comping, syncopated synth bass, four-on-the-floor kick, and open hi-hats on the off-beats, you can instantly try trendy dance-pop progressions. Recommended BPM 110-125.
"Indie Rock" delivers 2000s post-punk revival sound. Twin clean guitars with bell-like sparkles create chamber-style indie rock, while driving 16th-note hi-hat ghosts and octave-jumping bass anticipation push forward momentum. Recommended BPM 130-150.
Perfect for producers who want to take it into a DAW. Export to Audio / MIDI ready.
Try any Pro groove for 10 minutes free. Tap a Pro groove and watch a single ad to unlock 10 minutes of full playback. Love it? Subscribe to Pro to keep it unlocked permanently.
Get notified when new grooves are added. We'll send a brief notification whenever a new groove joins OtoTheory. Opt in from the dialog after your first try — turn it off anytime in Settings.
[7-day free trial] Cancel anytime with one tap.
Feedback: support@ototheory.com
2.14.0 May 27
Two new Pro grooves are now available.
"Bossa Nova" delivers authentic Brazilian jazz with six instruments: Nylon Guitar, Acoustic Bass, Drop 2 voicing Piano, Vibraphone, Tenor Sax, and Brazilian Clave Drums.
"Lounge Jazz" recreates modern piano trio jazz with sustained Piano comping, ECM-style Ride cymbal, walking Acoustic Bass, sub-tone Tenor Sax, and feathered Drums.
Both shine as Lo-Fi / Chillhop / Jazz Hop sampling sources. Export to Audio / MIDI and drop them into your DAW. Recommended BPM: Bossa Nova 100-130 / Lounge Jazz 70-115.
[7-day free trial] Cancel anytime with one tap.
Feedback: support@ototheory.com
2.12.0 May 24
■ Ideas for how to end your song
At the end of your progression, OtoTheory now suggests fitting ways to finish — a strong close, a soft landing, or a "keep going" feel. Place the ending you want with a single tap.
■ The voicing you pick is the voicing you hear
The guitar chord shapes you choose in Chord Shapes are now reflected in playback. What you see matches what you hear, so your ideas come out just as you imagined.
■ Improved guitar tone
Re-tuned the sound so the difference is clearly audible on your device.
■ Clearer input tabs
Added icons to the tabs on the chord-building screen.
A one-time "lifetime" purchase is also available alongside the monthly and yearly plans — no subscription required.
Plus other small improvements.
Feedback: support@ototheory.com
more Version 3.10.0 17h ago
Data Linked to You The following data may be collected and linked to your identity:
Data Not Linked to You The following data may be collected but it is not linked to your identity:
