Atelier — French Learning Platform

I started Atelier in January 2026 with one goal: build the French learning platform I wished existed when I started studying. Most options on the market either gamify the language into oblivion or bury learners under unstructured content. Atelier sits in between — real CEFR scaffolding from A1 through B2, with a learning loop that rewards consistency without infantilising the learner.
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The frontend is a Next.js 16 App Router project running React 19 with full server components and streaming. State for the lesson-runner sits in Zustand stores that hydrate from MongoDB on auth and persist progress optimistically — users can switch devices mid-lesson and pick up exactly where they left off. The exercise framework is extensible: drag-and-drop ordering, conjugation drills, gap-fill, dictation, multiple-choice, free-response with grading rubrics, listening comprehension, and translation pairs all share a common interface but render their own UI.
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The backend lives in Next.js Route Handlers with MongoDB as the primary store. Authentication is custom JWT with refresh-token rotation — no third-party auth provider — with secure HTTP-only cookies and replay protection. The subscription layer supports monthly, annual, and lifetime plans with prorated upgrades, gated content access, and webhook-driven entitlement updates.
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The whole UI is bilingual FR/EN via a translation layer that swaps at the route level. Performance budgets are tight: every lesson page hits LCP under 1.5s on mid-tier mobile, and the lesson-runner ships under 80kb gzipped.