Case study 07
Ielzy
Ielzy prepares candidates for IELTS across all four skills. Each skill has guides, lessons, practice sets, a mistake log, vocabulary and progress tracking, and timed mock tests run per skill or as a full exam, including a speaking test with a device check. A diagnostic on sign-up feeds a personal study planner with goals, a calendar, scheduled mocks and reviews, while vocabulary and grammar paths, flashcards, daily practice and an AI assistant fill the gaps. Behind it, an admin area manages the content library, media, users and plans.
No public site or source code. The architecture and the decisions behind it are described below.
- Founder & sole engineer
- Own product
- EdTech, AI
- IELTS, Exam Preparation, Adaptive Learning, Mock Tests, Study Planning
- Next.js
- React
- TypeScript
- Better Auth
- Drizzle
- Neon Postgres
- Cloudflare R2
- Resend
- Tiptap
What Ielzy does
- Reading, Listening, Writing and Speaking modules, each with guides, lessons, practice, a mistake log and progress
- Timed mock tests per skill and as a full exam, with results and answer review
- Speaking tests with a microphone and device check
- Onboarding diagnostic and a personal study planner with goals, a calendar, scheduled mocks and reviews
- Vocabulary learning paths, collections, flashcards, quizzes and daily practice
- Grammar lessons, quizzes, daily practice and a mistake log
- Writing task bank, model articles, drills and writing reports
- An AI study assistant
- Achievements and progress tracking across skills
- Admin content library for test series, papers and parts, with previews and a media library
- Email and Google sign-in, with email verification and password reset
The problem
IELTS candidates juggle PDFs, YouTube videos and scattered practice tests, with no clear sense of which skill is holding their band score back or what to study next.
Approach
Every skill follows the same loop: learn, practise, review your mistakes, track progress. A diagnostic at sign-up seeds a study plan, and mock tests that mirror the real exam feed results back into it. All content is authored in an admin area, so new tests and lessons ship without code changes.
Key decisions
- D1
One loop per skill
Reading, Listening, Writing and Speaking share the same guide, practice, mistakes and progress structure, so moving between skills feels familiar.
- D2
Direct-to-storage media
Listening audio and charts upload straight to Cloudflare R2 with short-lived presigned URLs, so large files never pass through the app server.
- D3
Content as data
Test series, papers and passages live in the database and are managed in the admin, not hard-coded into pages.
My contributions
- Came up with the product and defined its scope across the four IELTS skills
- Built the whole app alone: the Next.js App Router frontend, Drizzle schema and migrations on Neon Postgres, and Better Auth sign-in
- Built the mock-test engine for timed per-skill and full exams, with results and review
- Built the admin content system, with a Tiptap editor and a media library on Cloudflare R2