Autochords vs OtoTheory

Autochords is an iPhone and iPad app that helps songwriters find chord progressions and learn chords on guitar, piano and ukulele. Choose a progression style and key to see a main progression and alternatives for other song sections. Progressions can be previewed at a selected tempo with piano, guitar or ukulele playback, and the app provides diagrams for each instrument. Its built-in library contains dozens of progressions across styles of western music, though some require PRO. The free plan provides the app's free features. PRO adds more progressions, favorites, tempo changes, color themes, custom progressions and MIDI export. Export uses the iOS share sheet to open files in compatible apps, including desktop DAWs such as Logic or GarageBand. PRO costs $2.99 a month, $12.99 a year or 29.99 USD once for lifetime access. If a PRO subscription expires, existing favorites and custom progressions remain accessible, but users cannot add or remove favorites or create or delete custom progressions. Astrocode Pty Ltd develops the app, which is operated by a solo developer.

OtoTheory is a chord progression builder and music theory companion for guitar, bass, and keyboard players, songwriters, and DAW users. Its iOS app can identify chords, key, and song sections from imported audio or an on-device guitar or piano recording. Users can paste progressions from ChatGPT, Claude, or Gemini for Roman numeral analysis and playback with grooves. The app lists 19 groove patterns and more than 50 progression presets; OtoTheory AI suggests chords using musical feel, theory, and emotion. Pro exports MIDI in Groove, Groove + Theory, or Chords Only modes, including BPM, section markers, and chord names. The maker says those exports can be used with Logic Pro, Cubase, Ableton, and other DAWs. OtoTheory is available on iOS and the web, but the web version has fewer features and Pro is iOS-only. The free iOS plan allows three local sketch saves and excludes MIDI and audio export. Pro is listed from $5.99/mo; its annual plan is $49.99/year, and Lifetime costs $99.99 once.