# OtoTheory - Chord Progression — Songwriting & Scale Practice > Intuitive chord progression builder with AI analysis and DAW integration. (iPhone/iPad app by NORITO HARADA.) - Source: https://appshunter.io/ios/app/ototheory-chord-progression/id6755084287 (this page in markdown: same URL + `.md`) - Developer: [NORITO HARADA](https://appshunter.io/developer/1851826664) - Category: Music, Education - Price: Free with in-app purchases (on sale, was $2.99) - Age rating: 4+ - Requires: iOS 17.0 · 51 MB - Languages: American English, Japanese - Released: 2025-11-14 - Data updated: 2026-08-29 - Monetization: freemium - User reviews in markdown: https://appshunter.io/ios/app/ototheory-chord-progression/id6755084287/reviews.md ## What is OtoTheory? 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 ## Key features - AI Chord Import - Chord Progression Builder - 15 Groove Patterns - 50 Presets - OtoTheory AI Suggestions - MIDI Export - Fretboard & Keyboard Views ## Pricing and in-app purchases Base price: Free. **Subscriptions** | Subscription | Price | Period | | --- | --- | --- | | OtoTheory | $4.99 | per month | | OtoTheory Pro (Annual) | $49.99 | per year | ## Recent user reviews (10 of 10) All indexed reviews: https://appshunter.io/ios/app/ototheory-chord-progression/id6755084287/reviews.md ### 5/5 — 気軽にコード進行が作れて楽しい *2026-08-27* 音楽理論を知らなくても、コード選んで鳴らして良ければ残す、というだけで 作曲が進んでいきます。触ってて楽しいです！ スマホでちょっと空いた時間にできるのもありがたいです…！ あとから直せるので雑に作り始められるのも自分には合っていました。 MIDI で書き出せるから、DAW に持っていってそのまま本格的に作り込めるところが魅力的でした。 ### 5/5 — The only one that lets me fix the chords *2026-08-22* I've run songs through a bunch of chord detection sites. They're all a little off somewhere, or they just hear a chord differently than I do, which is fair enough, but you're stuck with whatever it hands you. Here you import the song, it pulls out the chord progression, and then you can go in and change the ones you don't agree with. That's the whole difference for me. ### 5/5 — Slash chords whenever I want them *2026-08-20* Been writing songs with this for a while. The suggestions got a lot better with this update, more options, weirder chords, and you hear them instantly, so you can pick by ear without knowing why they work. Slash chords are still the thing I use most, always right there in the list. Then MIDI export into my DAW when it's done. No complaints really. ### 5/5 — Best MIDI export of any sketch app *2026-08-18* The MIDI export alone is worth it. Chords land in my DAW as a real chord track that reads correctly, and the drums come out as separate parts rather than one merged track, so there's nothing to untangle before I start arranging. It has made everything that happens before the DAW so much easier. I rough out a chord progression idea in OtoTheory, send it over as MIDI, and do the real editing in my DAW — that flow is now settled for me. Recent updates have been excellent. Keep going. ### 1/5 — 何をしたらいいかわからない *2026-07-03* 「提案」を押して「最初のコードを選ぼう」という指示のもとコードを選ぶと、「提案がありません」と仕事放棄するため何をどうすればいいかわからなくなる。チュートリアルが欲しい。 **Developer response:** ご不便をおかけして申し訳ありませんでした。ご指摘の「提案」を押すと『最初のコードを選ぼう』のまま先に進めなくなる不具合は、最新アップデート（v3.5.0）で修正済みです。コードを選んだあとに、きちんと次のコードの提案が表示されるようになりました。 また、チュートリアルのご要望もありがとうございます。おっしゃる通り「まず何をすればいいか」が分かりにくい点は課題として認識しており、初めての方向けの案内を順次改善しています。 もしアップデート後もうまくいかない場合は、support@ototheory.com までお気軽にご連絡ください。貴重なフィードバックをありがとうございました。 ### 5/5 — 買い切りプランに期待 *2026-06-06* 素晴らしいアプリで、作曲が捗ります。お願いするとしたら、買い切りの課金プランがあれば有り難いです。広告非表示だけはサブスクでも、機能の開放だけでも買い切りがあれば即課金します！ **Developer response:** この度は嬉しいレビューを、そして貴重なご要望をありがとうございます。 「作曲が捗る」とのお言葉、開発の大きな励みになります。 作曲でのご活用について、ぜひ詳しくご意見をお聞かせいただきたく、 もしよろしければ下記までメールをいただけますと幸いです。 その際、ご要望いただいた買い切りプランを含め、今後の方針についても 個別に情報を共有させていただければと思います。 support@ototheory.com 引き続き OtoTheory をどうぞよろしくお願いいたします。 ### 5/5 — The fretboard visualization is brilliant. *2026-05-14* I know my theory, but mapping out specific scale notes and chord tones in unfamiliar keys used to slow me down. I’d have to think about the fretboard geometry instead of just making music. With this app, no matter what progression or scale I choose, it visualizes everything perfectly. Having both the scale and chord tones displayed clearly on the fretboard is amazingly helpful. Such a smart and convenient tool! **Developer response:** Thank you so much for the wonderful review! We're thrilled that seeing the scale and chord tones together on the fretboard lets you focus on making music instead of working out the geometry — that's exactly what we built OtoTheory for. Your feedback is incredibly valuable to us and will help guide our future improvements. If you ever have ideas or requests, please reach out anytime at support@ototheory.com — we'd love to hear from you. Thanks again for the support! ### 5/5 — テクノ制作の幅と効率が劇的に上がるツール *2026-02-25* DTMでテクノを作っているのですが、コード理論が全く分からず、いつも色んな音を重ねて「雰囲気」だけで作っていました。でもこのアプリを使うと、「ここでこう盛り上げる」といった曲の展開を感覚ではなく「狙って」作れるようになります！ さらに最高なのが、アプリ内で作ったアレンジをそのままMIDIエクスポートしてDAWに持っていけること。出力されたMIDIデータをAbletonに読み込んで、自分好みのシンセに差し替えたりフレーズをいじって曲を発展させられるので、制作効率が爆上がりしました。 **Developer response:** 詳しいレビューをありがとうございます！「雰囲気」ではなく「狙って」曲の展開を作れるようになった、と感じていただけたこと、とても嬉しく思います。さらに、MIDIエクスポートでAbletonに持っていって、お好みのシンセに差し替えたりフレーズを発展させたりと、まさに私たちが思い描いていた使い方で制作に役立てていただけていて、開発チーム一同とても励みになります。 いただいたご意見は大変参考になり、今後の改善にしっかり生かしてまいります。「DAW連携でこんなことができたら」といったご要望がありましたら、ぜひ support@ototheory.com までお気軽にご連絡ください。これからもDTM制作のお供にしていただけるよう進化させていきます！ ### 5/5 — 手軽で楽しい！ *2026-02-21* この手のアプリは使い方が分からなくて、 すぐに使わなくなりますが、 このアプリは何となく触っていたら、すぐに使い方が分かってきます。 有名曲のコード進行などを入力して、ギターソロやアルペジオの練習をして楽しんでいます。 まだまだ、細かい所は改善の余地がありますが、頻繁にアップデートもされているようで、その度に使いやすくなっています。 シンプルで使いやすい所はそのままに、より楽しく、多彩な機能を追加してくれればと思います！ 忙しい毎日でも少しの隙間時間で楽しめるのがgoodなアプリです♪ **Developer response:** 嬉しいレビューをありがとうございます！「何となく触っていたら使い方が分かってきた」と感じていただけたこと、そして隙間時間に楽しんでいただけていること、開発チーム一同とても励みになります。シンプルで使いやすい部分は大切にしながら、もっと楽しく多彩に進化させていきたいと考えています。 いただいたご意見は大変参考になり、今後の改善にしっかり生かしてまいります。「こんな機能がほしい」といったご要望がありましたら、ぜひ support@ototheory.com までお気軽にご連絡ください。これからもOtoTheoryをよろしくお願いいたします！ ### 5/5 — The best way to visualize and write guitar leads. *2026-02-13* I use this app whenever I need to compose a melody or a solo. Seeing the scale and chord tones light up on the fretboard helps me navigate the neck with confidence. It allows me to build phrases visually, ensuring every note fits perfectly with the chord progression. It's a huge boost to my creative workflow. **Developer response:** Thank you for the awesome review! Helping you navigate the neck with confidence and build phrases that fit the progression is exactly what we hoped OtoTheory could do, so hearing it's become part of your creative workflow truly makes our day. Your feedback means a lot to us and will help shape future improvements. If you have any feature ideas or requests, please don't hesitate to email us at support@ototheory.com — we'd love to hear them. Keep those leads coming! ## Frequently asked questions about OtoTheory ### Do I need music theory knowledge to use OtoTheory? No, OtoTheory is designed for users without prior theory knowledge. Simply pick a key and scale, and the app will automatically suggest correct chords. ### What is the difference between the free and Pro versions of OtoTheory? The free version offers all creative tools, including AI import, chord builder, grooves, presets, and AI suggestions. OtoTheory Pro unlocks unlimited export, unlimited saves with iCloud sync, and an ad-free experience for $2.99/month. ### Can OtoTheory export to DAWs like Logic Pro or Ableton? Yes, the Pro version allows MIDI export of your groove arrangement, including chord tracks, guide tones, bass tracks, and section markers, making it compatible with major DAWs. ### Does OtoTheory have ads? The free version of OtoTheory contains advertisements. The Pro subscription offers an ad-free experience. ### What devices is OtoTheory available on? OtoTheory is available on iPhone and iPad, supporting seamless syncing between devices with the Pro subscription. ### How often is OtoTheory updated? The app was last updated on August 12, 2026, indicating active development and support. ### What are the subscription options for OtoTheory Pro? OtoTheory Pro offers a monthly subscription for $4.99 with a 7-day free trial, and an annual subscription for $49.99, also with a 7-day free trial. ### Can I use OtoTheory for scale practice? Yes, OtoTheory provides scale guides for solos and features a fretboard and keyboard view where chord tones are highlighted in real-time during playback. ## Version history (last 5 releases) ### 3.16.0 — 2026-08-26 Grooves now follow the chords you choose far more closely. We sharpened chord interpretation across 48 grooves, so the tensions you specify come through. And you can now see, right where you pick them, what each groove actually does. - Sharper chord interpretation Chords with tensions such as Fmaj9 and F7(b9) now carry that colour into the backing. Bass and pad parts follow your chord changes in more places, too. Exports match: audio and MIDI carry the chord as written, slash chords included. - Groove descriptions In the mixer you can read what each groove is built from and what it suits. Where you used to choose by name and sound alone, there is now something to go on. - See which grooves add colour Grooves that build their atmosphere from notes you did not specify, such as 9ths and 13ths, now carry a sparkle badge, along with how much they add. So you can tell apart the times you want your chord played straight from the times you want the genre's flavour. Feedback: support@ototheory.com ### 3.15.0 — 2026-08-24 No more losing a progression because you forgot to save it. Your work is now kept in the library from the moment you add a chord. No save button to find, no dialog to answer. ■ What you write stays written Autosave starts as soon as you add a chord or give the sketch a name. From then on it updates quietly as you edit, and your work stays put when you close the app or move to another screen. Half-finished ideas no longer disappear. ■ Clearer save limits The free plan now has a single limit of 3 saved sketches, replacing the confusing split between a Create-only slot and an overall limit. When you reach the limit, we explain why first and then show your options. We've also fixed a batch of save-related issues, including sketches losing their name or key when reopened, and shared `.ototheory` files failing to load. Feedback: support@ototheory.com ### 3.14.0 — 2026-08-18 Chord suggestions have been rebuilt from the ground up. Tabs are gone: the chords you can play next and the richer voicings built from them now sit together. Plus a new groove, Salsa. ■ Suggestions in a single panel The panel now follows the slot you're on and shows only what's relevant, in order. Even an empty slot surfaces connecting chords along with their extended and slash-chord forms, so there's always a way to add color to a progression. ■ New "Salsa" groove A 3-2 son clave with a rolling bass, piano comping, horn stabs, and conga and timbale percussion. Drop in your chords and a full live-band Latin arrangement plays back. Chord forms now take effect when you apply them and can be undone at any time, tapping a slot previews its sound, and we've corrected how a number of presets voice their chords. Feedback: support@ototheory.com ### 3.13.0 — 2026-08-12 Drums now export to MIDI as separate parts. Kick, snare, hi-hat and more land on their own tracks, so swapping sounds and mixing in your DAW starts the moment you import. ■ Per-part drum export Drums in MIDI exports are now split into one track per part. Parts you don't use aren't created at all, so you can start editing right away. ■ Chord guide imports silently The guide track for DAW chord tracks now opens with its volume down, so it won't bleed into playback the moment you import. We've also made a number of smaller improvements. Feedback: support@ototheory.com ### 3.12.0 — 2026-08-11 We've added a short in-app survey. The team reads every response, and your feedback has already shaped new features and improvements. Tell us what you'd love to see next. ■ Quick survey You may occasionally see a short survey (just a few questions) on the home screen. It takes 1–2 minutes and is completely optional — tap "Later" to dismiss anytime. Your answers help decide what we build next. Plus copy refinements and small improvements throughout. 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User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-29.*