DSA & System Design

Build track

Know what to plug in, and where.

Every app is a handful of services joined together: login, a database, somewhere to run, a queue for slow jobs. Learn what each one does, compare the options, and see exactly how they connect.

Build my architectureBrowse the parts
Your app's architectureServices in this stack: Vercel, Supabase, Clerk, Inngest or Trigger.dev, Resend (or AWS SES), Upstash Redis.HTTPSwho is this?querieshot readsslow jobspulls jobssendsYour usersbrowser or phonePush to Git and your Next.js app is live, with serverless and edge functions.VercelHostingDrop-in sign-in screens, user management and sessions, hosted for you.ClerkAuthPostgres plus login, file storage and an instant API in one dashboard.SupabaseDatabaseRedis you call over HTTP, built for serverless and pay-per-use.UpstashCacheA hosted job runner. You write functions, it calls them with retries and logs.Job runnerQueues and jobsA small program that takes jobs off the queue and does them in the background.Workerdoes the slow jobsSend email from your code with one API call. SES is the cheaper, rougher cousin.ResendNotifications

How this works

  1. 1Pick what you are buildingA SaaS, a store, a chat app, an AI tool. We start you with the parts it usually needs.
  2. 2See the architectureBoxes and arrows, drawn for you. Press play to watch a sign-in or a payment travel through it.
  3. 3Click any boxRead why it is there, compare the alternatives, and follow the steps to connect it.
  4. 4Hand it to your AI toolCopy the whole plan as a prompt for Cursor, Claude Code or any coding assistant.

Start from a product

The parts of an app

Grouped by the job they do. Not sure where to begin? Go top to bottom: that is the order most apps get built.

Run it

Where your code lives and how requests reach it.

Remember it

Where data and files are kept so they survive a restart.

Protect it

Who is allowed in, and what they are allowed to do.

Do it later

Slow work that should not make the user wait.

Add powers

Optional features that make the app feel finished.