Fretstart

Fretstart is a daily practice coach for intermediate blues and rock lead guitar. Open it and it tells you exactly what to practice today: a five-step session built from a 32-week curriculum, with every scale, lick, and chord drawn on an interactive fretboard, a metronome and backing groove running underneath, and a streak keeping you honest.

I built it for myself — I wanted one place for all the scales, voicings, and chords instead of five browser tabs, plus enough gamification to make twenty minutes a day actually happen. It went from an empty folder to live in production in seven days.

Features

• A 32-week authored curriculum: two parallel tracks (blues and rock), 448 authored days, from owning box 1 through repertoire, comping, and playing with other people
• The 5-day micro-arc: each week's material repeats at a rising tempo with shifting intent — learn it slow, clean it up, apply it, push it, record it — which is how practice actually works
• Interactive fretboard everywhere: canvas-rendered diagrams for every scale, arpeggio, and chord, switchable between note names and degrees, whole neck or one box
• Mic-checked bends: the app listens to your bend attempts and reports the pattern — "reliably 30 cents flat" is a fixable habit, and no video course can hear you
• Recording checkpoints: takes on day 1 and every fourth week, never pruned, with a comparison view that defaults to the widest span — so you can hear day 1 against day 224
• Streaks that don't lie: a lapsed streak reads zero immediately, and the one dishonest stat from the prototype was deleted before launch
• Guitar-shaped audio: the metronome, groove player, and scale playback use Karplus-Strong plucked-string synthesis rather than beeps
• Push reminders: one a day, at your hour, in your timezone, skipped on any day you already practised
• Guest mode: the whole app works without an account, state in localStorage, reconciled into Supabase if you sign in later
• Published, indexable content: the curriculum weeks, scale library, licks, and solos are real SEO pages readable without an account

My Contributions

• Built solo in one week with AI-assisted development: 175 commits Aug 15–21, run through the same issues → PRs loop as Multiplay — five audit rounds filed 146 issues and closed 140 of them
• A content checker for musical truth: check:content asserts note pitches, legato playability, and every fret/note claim the prose makes against the interval arrays the diagrams draw — because a lick can be out of key while TypeScript is perfectly happy
• Curriculum authoring: all 64 week-datasets across both tracks, with prose and facts split into separate modules so a page cannot contradict its own diagram
• Test discipline: 579 tests over the logic where a silent bug costs a user their streak — day boundaries, the lapse rule, guest reconciliation — each broken once on purpose to prove it can fail
• Privacy-first measurement: page views counted with no cookie, no identifier, no consent banner; the practice screen is never counted

Technologies

• Next.js 15 + React 19: App Router, PWA with service worker and installable manifest
• Supabase: Postgres with RLS, magic-link auth, and column-level grants hardened across 20+ migrations
• Web Audio API: Karplus-Strong synthesis, metronome scheduling, and pitch detection for the tuner and bend check
• Web Push + GitHub Actions: VAPID-keyed reminders on an hourly scheduler
• S3-compatible storage: recording uploads with presigned URLs, a size allowance, and a nightly sweep
• Vitest: 579 tests, plus the custom content checker in CI

Why It's Cool

Most practice apps are either a content library or a habit tracker. Fretstart's bet is that the two only work together: the curriculum decides what today is for, the diagrams and audio make it playable, and the streak and checkpoint recordings make progress visible enough to keep going. And it has the one feature a video course structurally can't offer — it listens back. The bend trainer turns "does that sound right?" into a number, which matters because an intermediate player's ear is exactly the thing still being trained.

The engineering story is on the blog: The Build Was Green and the Lick Was Unplayable, about what it takes to test music instead of code.

Try It Out

Visit fretstart.com — the 32-week path and the scale and chord library are readable without an account, and the daily practice screen works as a guest.