Ten modules that end in a multi-tenant feature-flag service doing 10k evaluations a second on Fastify, Prisma, BullMQ, pino, and OTel.
You can write JavaScript. The gap shows the first time someone asks you to keep a Node service up: one blocking parse of a 40MB payload freezes every open connection, a forgotten `await` turns a real error into a silent unhandled rejection, and the container takes SIGTERM mid-request because nobody wired a drain. Node's single thread is a gift right up until it isn't, and no tutorial that stops at `app.listen(3000)` tells you which side of that line you're on. This course starts at `node --version` and ends with `flagrr`, a multi-tenant feature-flag service shaped like LaunchDarkly. Along the way you pin versions with corepack, settle ESM against CommonJS, make TypeScript strict enough to hurt, cancel work with AbortController, stream files too big for memory, push CPU work to worker_threads, and test HTTP handlers without booting a server. Then the production half: Prisma or Drizzle against Postgres, Fastify with JSON-Schema validation, BullMQ workers with dead-letter queues, pino logs, OTel traces, and a distroless image that exits cleanly. A 2026 stack throughout — `--watch`, `--env-file`, pnpm workspaces, no nodemon.
Built by Lakshya Kumar
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Turn on the checks that catch real bugs, trade `any` for `unknown`, and run .ts files directly with tsx instead of waiting on a build.
Run work in parallel, cancel it mid-flight with AbortController, and find the missing `await` that quietly swallowed your exception.
fs/promises, pipelines, undici, child_process and worker_threads — move bytes and CPU work without stalling the single thread.
Use the built-in runner or vitest, hit routes with supertest, intercept outbound calls with MSW, and get coverage numbers you trust.
Lay out src and dist, wire an exports map both ESM and CJS consumers respect, and add Turborepo caching only once builds justify it.
Pick an ORM for a defensible reason, stop Node's pool from exhausting Postgres, and kill the N+1 before it reaches production.
Validate requests from JSON Schema, keep plugins encapsulated, and close on SIGTERM without dropping in-flight requests on the floor.
Retry with exponential backoff, park poison jobs in a dead-letter queue, schedule repeatable work, and watch it all from bull-board.
Validate env with zod, get readable stack traces from source maps, drain on SIGTERM, and hand ops an image that isn't a gigabyte of root.
Complete all modules, then submit the required number of capstone projects. Each must earn a passing rating from an admin reviewer.
Build `flagrr`, a feature-flag service in Node.js. Required: Fastify API for flag evaluation, Prisma + Postgres with multi-tenant row-level isolation, BullMQ worker for evaluation logging + nightly rollups, an SDK-shaped JSON response (flags + variants + targeting rules with precedence: percentage rollout, attribute matching, rule precedence), pino structured logs, OTel traces, a Dockerfile + docker-compose. Submit: repo URL, a Loom demonstrating tenant A and tenant B isolation, and a load-test (autocannon or k6) showing 10k flag evals/sec on a 4-core box.
I'm considering Capstok's "Node.js: From Zero to Production Service" course. It covers the runtime, modern TypeScript, async + AbortController, I/O (streams, fetch, child_process), testing (node:test, vitest), pnpm + monorepo, Prisma/Drizzle, Fastify, BullMQ workers, and a production stack (pino + OTel + Docker). Capstone is a multi-tenant feature-flag service. Context: 1. My current JS/TS level: [e.g. "frontend dev", "Express tutorials", "scripts only"] 2. The closest I've come to a Node backend service: [e.g. "Express demo", "Next.js API routes", "never"] 3. What I want at the end: [e.g. "ship a Node service", "interview-ready", "build LaunchDarkly-style"] Answer: - Which 2 modules will pay back fastest in my next 3 months? - A real bug I'll ship in my first Fastify service that this course catches. - Is 50 hours worth it for me, or should I learn Go instead? Honest pick. - What this course will NOT teach (Next.js, frontend frameworks, Bun specifics)?
Read alongside Module 2.