📖 Start the course  ·  ❓ 130 interview questions  ·  🌐 Read it as a site

---

The entire course is in this repo. No signup, no video, no "part 2 coming soon".

16 chapters, each a single readable page. Every concept is language-agnostic — the ideas hold whether you write Node, Python, Go or Java. Every 🚨 is a trap that takes down real production systems.

16 chapters

130 interview questions

120+ glossary terms

~15,000 words, all in this repo

---

Contents

Each chapter is its own page. Click one and start reading.

The course

	Chapter	You'll learn
0	🌱 Foundations	What a backend actually is, and what happens when you type a URL	2 min
1	🌐 HTTP	Requests, responses, methods, status codes, cookies	3 min
2	🖥️ Servers & concurrency	How one machine serves thousands of people at once	3 min
3	🔌 APIs	Designing a contract other people build on	4 min
4	🗄️ Databases	Modelling, indexes, EXPLAIN, transactions, race conditions	8 min
5	🔐 Security	Auth, passwords, JWT, OAuth, and the bugs that cause real breaches	5 min
6	🔁 Caching & queues	Serve it fast, do the slow work later	3 min
7	⚡ Performance	p95/p99, profiling, and where the time actually goes	3 min
8	🕸️ Reliability	The network will fail. Design like it already has.	3 min
9	🚀 DevOps & deploys	Containers, CI/CD, zero-downtime deploys	3 min
10	🧠 System design	The method, the maths, and the classic problems worked through	3 min

The interview

	Chapter	What's in it
11	🎯 The interview round	The 45 minutes minute-by-minute, what they grade, how people fail	2 min
12	📖 Backend glossary	120+ terms, each defined in one sentence	12 min
13	❓ 130 interview questions	Design-X prompts, deep dives, concepts, estimation, trade-offs	14 min

Reference

	Chapter	What's in it
14	📋 Cheat sheets	Status codes, latency numbers, a red-flag checklist	2 min
15	📚 Where to go next	The best free resources, curated	2 min

---

⏱️ Only have 20 minutes?

Read these three and nothing else. They cover more real-world breakage than the rest combined:

	Read this	Because
1	Indexes	Missing indexes cause more slowness than everything else put together
2	The N+1 query	You have written this bug. You just don't know it yet.
3	Timeouts	One slow dependency takes down your whole service without them

---

🧭 Pick your path

If you are…	Start here	Why
🌱 New to backend	Chapter 0 · Foundations	Starts at "what is a server". Assumes nothing.
🎨 A frontend dev switching over	Chapter 1 · HTTP → then jump to Databases	You already know HTTP from fetch(). Databases are the real gap.
🔧 Already shipping APIs	Databases → Performance	Fill the holes: indexes, transactions, N+1, p99
🎯 Prepping for interviews	The interview round → 130 questions	The method, then the full question bank
🚨 On call, something's broken	Reliability	Timeouts, retries, circuit breakers, the outbox
🧠 Just want the vocabulary	Glossary	120+ terms, one sentence each

---

Why this exists

Most backend tutorials teach you a framework. You finish, you can wire up an Express route, and you still can't answer "why is this slow?" or "what happens when two people click Buy at the same time?"

BackendPath teaches the concepts underneath — the ones that stay true whether you write Node, Django, Spring or Go.

The promise: finish this and you can look at any backend, in any language, and know roughly how it works and where it will break.

A taste of what that means in practice — from Chapter 4 · Databases:

- ❌ BEFORE
  Limit  (actual time=142.318..142.325 rows=20)
    ->  Sort
          ->  Seq Scan on orders                  ← read the WHOLE table
                Filter: (user_id = 42)
                Rows Removed by Filter: 1988688   ← threw away 2 MILLION rows 😱
  Execution Time: 142.401 ms

+ ✅ AFTER  (CREATE INDEX ON orders (user_id, created_at DESC))
  Limit  (actual time=0.031..0.038 rows=20)
    ->  Index Scan using orders_user_id_created_at_idx on orders
          Index Cond: (user_id = 42)              ← walked straight to them
  Execution Time: 0.061 ms                        ← 2,300× faster

---

🌐 Prefer it as a website?

The same material also runs as an interactive site — backend.nextjoblist.com — free, no signup. It adds 68 lessons with quizzes, progress tracking, ⌘K search, and every code example switchable between JavaScript, Python, Go and Java.

Lessons — docs layout, TOC, quizzes, 4 languages	130 interview questions — each linked to where to learn it
The roadmap — 11 stages, 68 lessons, your progress tracked

Run it yourself

npm install
npm run dev        # → http://localhost:5173

Command
npm run dev	dev server
npm test	31 tests
npm run build	production build → dist/

Content is data; the app is a renderer. Lessons are plain Markdown in public/content/, listed in roadmap.json:

{
  "id": "my-lesson",                  // → /lesson/my-lesson
  "title": "My Lesson",
  "file": "01-http/my-lesson.md",
  "estMinutes": 8,
  "quiz": [{ "q": "…", "options": ["A", "B"], "answer": 1, "explain": "…" }],
  "resources": [{ "title": "…", "url": "…", "type": "docs", "note": "…" }]
}

Put fenced code blocks for different languages next to each other and they render as one tabbed component (js · python · go · java).

The Pro Shelf reference pages live in src/pages/pro/, built from the vocabulary in ProKit.tsx.

---

Concepts, not frameworks.

Frameworks change every three years. The request lifecycle, indexes, transactions, caching, idempotency and failure modes don't.

Learn those, and you can pick up any backend, in any language, and know roughly how it works — and where it will break.

→ Start with Chapter 0 · Foundations

If this helped you, ⭐ the repo so the next person finds it.