Autochords vs ChordProgressions.org

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.

ChordProgressions.org is a free browser studio for creating, hearing, analyzing, customizing, and exporting chord progressions for guitar and piano. Its tools include generators, builders, finders, identifiers, analyzers, and transposers. Guitar shapes and piano voicings can be adjusted for tuning, capo position, difficulty, inversions, and fingering. Theory views show Roman numerals, Nashville numbers, chord functions, cadence points, borrowed chords, and an estimated key with confidence. The studio accepts MIDI input and imports MusicXML, project files, and plain-text chord sheets. Browser audio analysis creates an editable chord timeline with a confidence score. Exports include MIDI, WAV, chord-chart PDF, PNG and SVG diagrams, plain text, CSV, JSON, MusicXML, and share links. Projects autosave on the device, and imported files are read locally. Practice tools loop progressions with metronome and count-in, plus ear and playing exercises in every key.