OtoTheory

OtoTheory is a chord progression builder and music theory companion for guitar, bass, and keyboard players, songwriters, composers, 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 also 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, with BPM, section markers, and chord names; the maker says these 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 a smaller feature set and Pro is iOS-only. The free iOS plan allows three local sketch saves and does not include MIDI or audio export. Pro is listed from $5.99/mo, with a 7-day trial; the annual plan is $49.99/year and Lifetime is $99.99, paid once.

OtoTheory combines chord exploration, analysis, grooves, and MIDI export, with the broader feature set limited to iOS. Check the web limitations and free-plan export restriction against how you plan to work.

OtoTheory suits guitar, bass, and keyboard players who want help exploring chord progressions, as well as songwriters, self-learners, composers, and DAW users. The web version may suit users who need only its subset of features.

Overview

OtoTheory is a music-theory and chord-writing app for guitar, bass, and keyboard players, songwriters, and DAW users. It is best for people who want to move between analyzing songs and shaping progressions; its fullest workflow, including Pro, is on iOS.

Its appeal is the combination of harmony tools, groove playback, and a path to MIDI export. The trade-off is substantial on the free plan: only three local sketch saves, with MIDI and audio export unavailable.

Key features

OtoTheory supports both finding and building harmony. A progression generator, reverse chord lookup, voicing explorer, chord playback, and chord-chart export serve different parts of that work. Its catalog of more than 50 progression presets and 19 groove patterns can help users get an idea moving, though the presets are starting points rather than a substitute for shaping a progression to fit a song.

The iOS app analyzes imported audio or a guitar or piano recording on-device, identifying chords, key, and song sections. That makes it useful for learners trying to understand a song’s structure, as well as writers looking to study material before developing their own. Users can also paste progressions from ChatGPT, Claude, or Gemini for Roman numeral analysis and playback with grooves. OtoTheory AI suggests chords through three described dimensions—feel, theory, and emotion—giving writers another way to explore options.

Pro MIDI export provides Groove, Groove + Theory, and Chords Only modes, with BPM, section markers, and chord names. The maker says exports can be used in Logic Pro, Cubase, Ableton, and other DAWs. This is a practical bridge from a sketch to a DAW session, but it is a paid feature and the Pro plan is iOS-only.

Pricing

The Free plan costs nothing and includes the iOS app with three local sketch saves. MIDI and audio export are unavailable, so it works best for trying the core workflow rather than keeping a larger library of ideas or moving them into another music app.

Pro is iOS-only and includes unlimited MIDI and audio export, unlimited saves, iCloud sync, and Pro-exclusive grooves. It has a 7-day free trial and is billed monthly or annually; the annual plan is $49.99/year. The monthly rate is $5.99/mo. Pro fits regular users who need to preserve and export their work, but it does not extend those features to the web version.

Lifetime costs $99.99, paid once, billed as a one-time purchase. It is iOS-only and includes all Pro features forever, with unlimited MIDI and audio export, saves, and iCloud sync. It suits committed iOS users who prefer a one-time purchase; the free plan is the lower-risk choice for occasional exploration, with its save and export caps.

Platforms

OtoTheory is available on iOS and the web, but the web version offers only a subset of the iOS features, with fewer grooves and presets. Pro is restricted to iOS. Pro users can optionally sync through iCloud, and exported MIDI can be transferred to a Mac using AirDrop. Sketches are stored locally on the device or in the user’s iCloud account for Pro; web sketches are stored in browser localStorage.

The privacy policy says communications use HTTPS, iOS cloud sync uses Apple CloudKit’s encrypted infrastructure, and OtoTheory does not sell personal data. Support is available at [email protected], with typical replies within two business days, excluding weekends and holidays.

Who it's for

OtoTheory is a strong fit for beginners, self-learners, and songwriters or composers who work with guitar, bass, or keyboard and want theory tools alongside progression building. DAW users who want MIDI with chord names and section markers have a clear reason to consider Pro. It is a weaker fit for people who need the full feature set in a browser or want free MIDI export.

Pros and cons

Pros

• One workflow for analysis and composition: song analysis, progression tools, and AI-assisted suggestions support both studying harmony and developing ideas.
• Export has useful structure: Pro MIDI modes include BPM, section markers, and chord names, giving DAW users more context than a bare progression.
• Flexible iOS storage: Pro adds unlimited saves and optional iCloud sync, while sketches can otherwise remain local.

Cons

• Free use is tightly capped: three local saves and no MIDI or audio export limit its usefulness for ongoing projects.
• Uneven platform access: the web version has fewer grooves and presets, and Pro is unavailable there.
• Paid export: users who want to take progressions into a DAW need Pro or Lifetime.

Alternatives

For a broader directory of chord-focused tools, see Chord Finder Software.

• Autochords is worth considering for an iOS-only freemium option with a $2.99 monthly PRO plan; some progressions require PRO.
• ChordU suits readers who need Android, iOS, or web access; its $5.00 per month Premium plan includes uploads, MusicOnly mode, and downloads.
• Chord ai is an Android and iOS alternative with a free tier described as offering unlimited basic use; its Pro monthly plan is $9.00 per month.
• Chord Analyser is a free Android and iOS option with no trial; it may suit readers looking for a no-cost alternative.
• Chordio is available on iOS and macOS, making it an option for users seeking support across those Apple platforms.
• ChordSequence is a free Android and web option with no paywall or usage limit and WAV and MIDI export.
• Open—Shape is an iOS and web alternative for readers comparing another freemium chord tool.
• Roland Chord Director is a free Android and iOS companion app for GO:KEYS 3 and GO:KEYS 5, requiring a free Roland Account for pre-made chord patterns.

Verdict

Choose OtoTheory if you want an iOS-centered toolkit that connects song analysis and progression writing to structured MIDI export. Its strongest reason to buy is the breadth of that creative workflow; look elsewhere if you need Pro on the web, or want a free tool without the three-save and export limits.