Guitar toolkit: chords, scales, theory, and practice tools
The guitar toolkit with intelligent tools and visualizations to help you deeply understand the fretboard as one connected system.
Free to use. No account required.
The problem
Every tool shows you one thing at a time. Chord dictionaries. Scale finders. Isolated shapes on isolated screens. No tool shows you how they connect: which scale tones land on which chord tones, why a voicing works in one context and not another, or how the same CAGED pattern unlocks three different keys and modes. fretengine exists because the fretboard is one connected system, and your tools should be too.
Layer chords and scales together
Stack a Dm7 chord on top of D Dorian and the overlap is instant — every chord tone highlighted, every tension visible. Add more layers. Reorder them. Toggle them on and off. The fretboard stops being a mystery and starts being a map.
By the numbers
7,000+ chord voicings and scale patterns. 50+ chord types from major to altered dominant to slash chords. 40+ scales including pentatonics, modes, melodic minor, and beyond. All 12 keys.
For every level
Just learned your first scale? Look it up with built-in theory explanations. Intermediate and grinding on CAGED? Toggle zone overlays across the neck. Advanced and stacking altered dominants? Layer chord-scale relationships and see the voice leading. fretengine meets you where you are.
Practice tools built in
Precision metronome
Set the tempo, hit play, and keep exploring. The click runs in the background so practice never stops. Tap tempo, 20-300 BPM, beat accents.
Timeline sequencer
Build a chord progression, sync it to the metronome, and watch the fretboard change on every bar.
Note explorer
Learn every note on the neck by name or tone.
Built-in theory
Every chord and scale comes with interval breakdowns and plain-language explanations.
Our belief
Making music is fundamentally human. Technology should make you a better musician — not replace you. fretengine shows you the fretboard in ways that build genuine understanding.
Get started
Open the app and layer your first chord and scale. It takes about ten seconds to see what we mean.
Start exploring
Frequently asked questions
Is it actually free?
The core toolkit is completely free. No account required, no ads, works in any browser.
How is this different from a chord dictionary?
Most fretboard tools let you look up one chord or one scale at a time. fretengine lets you stack them: layer a chord and a scale on the same fretboard, toggle between them, see exactly where they overlap. Pair that with 7,000+ voicings, integrated practice tools, and built-in theory. We happen to believe it's also the best chord dictionary out there.
Do I need to know music theory?
No. Whether you just learned your first barre chord or you're exploring modal interchange and voice leading, fretengine meets you where you are. Every chord and scale includes built-in theory explanations.
Do I still need a guitar teacher?
There's no replacement for an excellent teacher and mentor! They will always be able to teach you things online tools and videos cannot. fretengine is a learning tool that can help you reach the next level in your journey, whether you have a teacher or not.
Which instruments are supported?
6-string guitar in standard tuning today. Let us know if you'd like to see support for new instruments!
Does it work on mobile?
Yes. Any modern browser, any device: desktop, tablet, or phone.