TTS Study Assistant

The TTS Study Assistant lets you select text on any webpage, save it as a note, hear it read aloud, and summarize it with AI for review. It’s a Chrome extension (Manifest V3), a Go/Fiber backend, and a React admin panel.

Architecture

Backend (Go) — Fiber for HTTP, PostgreSQL via GORM, JWT auth, OpenAI for summarization, deployed on Railway in a Docker container.
Frontend (React + TypeScript) — Vite build, React Query + Context for state, deployed on Vercel.
Extension — Manifest V3 service worker, Chrome Storage API for local state, Chrome TTS API for playback, content scripts for text selection.

Decisions worth noting

Source-based token lifetimes

Web sessions and extension sessions have very different UX expectations, so the access-token lifetime depends on where the request comes from:

func (s *AuthService) generateAccessTokenWithSource(userID, email, source string) (string, error) {
    var exp time.Duration
    switch source {
    case "extension":
        exp = time.Hour * 1        // long-lived: the extension isn't a browser tab
    default:
        exp = time.Minute * 15     // short-lived for web sessions
    }
    claims := jwt.MapClaims{
        "user_id": userID, "email": email,
        "exp": time.Now().Add(exp).Unix(), "iat": time.Now().Unix(),
    }
    return jwt.NewWithClaims(jwt.SigningMethodHS256, claims).SignedString([]byte(s.cfg.JWTSecret))
}

Refresh tokens rotate on use, and the source is tracked for audit.

Tracking TTS state by hand

Chrome’s TTS API doesn’t expose detailed playback state, so the background service worker keeps its own state machine (isPlaying, isPaused, currentText, queue) and broadcasts updates to the popup via chrome.runtime.sendMessage. The popup is a pure view of that state.

Notes schema

CREATE TABLE notes (
  id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
  user_id UUID NOT NULL,
  content TEXT NOT NULL,
  source_url TEXT, source_title TEXT, domain TEXT,
  summary TEXT, metadata JSONB,
  created_at TIMESTAMP, updated_at TIMESTAMP
);
CREATE INDEX idx_uid_did ON notes(user_id, domain);

Domain is derived from source_url on write so notes can be filtered by site without parsing URLs on every query.

Architecture

Decisions worth noting

Source-based token lifetimes

Tracking TTS state by hand

Notes schema

Links