Roadmaps

Backend Concepts

  1. Content and data

    1. Search system: build a search engine for a set of articles with indexing, ranking, and autocomplete
    2. Feed / timeline: a mini Twitter with follow, post, and a paginated feed
    3. URL shortener ⭐️: shortening, redirects, and click analytics
    4. CMS / blog platform ⭐️: posts, roles (admin/editor), image uploads
    5. Wiki / knowledge base: page versioning and full-text search
    6. Pastebin clone ⭐️: text snippets with expiry and private links
    7. Comments / reviews service: threaded comments, moderation, spam filter

  2. Users and transactions

    1. Auth service ⭐️: registration, JWT, refresh tokens, roles, password reset
    2. E-commerce backend: catalog, cart, orders, stock control
    3. Booking system: book classes or rooms, with double-booking prevention
    4. Payment / billing: subscriptions, invoices, idempotent webhooks (Stripe sandbox)
    5. Wallet / ledger: balances and transfers with transactions and audit log
    6. Voting / polls system: one vote per user, live results
    7. Marketplace: sellers, buyers, listings, and reviews

  3. Real-time and communication

    1. Chat : WebSockets, rooms, and message history
    2. Notification service: email, push, and Telegram with queues and retries
    3. Live collaboration: shared notes with conflict resolution
    4. Online multiplayer game server: lobbies, game state, leaderboard
    5. Video call signaling server: WebRTC signaling and rooms

  4. Processing and infrastructure

    1. Task queue / scheduler ⭐️: Celery or RQ with retries and a recurring jobs dashboard
    2. Rate limiter / API gateway: token bucket limiter and request routing
    3. File storage service: uploads, S3-style storage, signed URLs
    4. Image/video pipeline: upload, resize, thumbnail, and compress in background workers
    5. Logging and monitoring: collect metrics, build dashboards, add alerts
    6. Web crawler: queue, deduplication, and robots.txt rules
    7. Cache layer: add Redis caching to an existing app and measure the speedup
    8. Feature flag service: toggle features per user or percentage rollout
    9. Webhook delivery system: reliable delivery with retries and signatures

  5. Data and ML

    1. Recommender system: the project we planned above
    2. ETL pipeline: ingest CSV or API data, transform it, load it into a warehouse
    3. Analytics platform: event tracking, aggregation, and dashboards
    4. ML model serving: a model API with versioning and A/B testing
    5. Fraud / anomaly detection: rules plus a simple model on a transaction stream
    6. Chatbot / RAG backend: document upload, embeddings, vector search, answer API

  6. Domain-specific ideas

    1. Learning platform: courses, lessons, progress tracking, and quizzes
    2. Task / project manager: Trello-like boards, assignments, and deadlines
    3. Telegram bot backend: commands, state machine, and a database
    4. IoT data collector: ingest sensor data, store time series, and raise alerts
    5. Food or recipe planner: meal plans, shopping lists, and ingredient search

  7. Suggested learning order

    1. URL shortener or Auth service (basics)
    2. Task queue or Notification service (async and reliability)
    3. E-commerce or Booking (transactions and concurrency)
    4. Chat or Feed (real-time and scaling)
    5. Search or Recommender (data-heavy design)