Node.js course
Key takeaways.
Node is a runtime, not a framework; Express is one common web layer.
Node shines for I/O-heavy workloads; CPU-heavy tasks can block the event loop.
Event-loop health is everything; avoid long synchronous work and watch latency.
Streaming and backpressure awareness prevent memory blow-ups under load.
Clean structure (web/service/data layers) keeps growth manageable.
Dependency discipline (minimal packages, lockfiles, safe updates) is production hygiene.
Express APIs should use validation, stable response envelopes, and central error handling.
Integrations need timeouts, bounded retries, and consistent internal error codes.
Webhooks must be authenticated and idempotent to survive duplicate deliveries.
Reliability is engineered: idempotent jobs, backoff, rate limiting, and observability tied to real user journeys.
In-depth breakdown.
Node.js [WC - C14] treats server-side JavaScript as an operational discipline, not just syntax reuse. It starts with runtime reality: Node is optimised for I/O, using a single-threaded event loop with background threads for I/O work, so performance depends on workload and event-loop health. From there it builds a mental model for async execution, microtasks vs macrotasks, backpressure, and streaming, so systems stay responsive under load.
The course emphasises maintainable structure: thin entry points, configuration layers, feature-based folders, and business logic kept separate from request/response objects. Dependency management is treated as production-critical: intentional packages, dev vs prod installs, lockfiles for reproducibility, and incremental updates backed by tests or smoke checks.
Express is used as the practical layer to build APIs: resource-based routing, middleware for validation/logging/rate limits, stable response envelopes, and safe, centralised error handling. Integrations extend this into real-world reliability: calling external APIs with timeouts, controlled retries, internal error codes, and webhook verification with signature checks plus idempotency for duplicate deliveries. Security hygiene runs throughout (secrets, least privilege, safe logging), then storage patterns (signed URLs, public vs private assets), and finally scheduling/jobs with idempotent cron work, backoff, alerting, and operational dashboards, grounded in a Replit-ready workflow.
Course itinerary.
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Runtime basics
Event loop concept
Common project structures
npm ecosystem
Lockfiles
Safe update habits
Asynchronous programming
Modules in Node.js
Real-world use cases
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Routing
Middleware
Params and query strings
Response shapes
Error handling
Project structure
Performance optimisation
Security best practices
Testing and documentation
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Calling external APIs
Timeouts and retries
Error discipline
Receiving webhooks
Idempotency
Basic audit logging
Security measures
Testing and monitoring
Best practices for API integrations
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Security basics
Input validation mindset
Avoid logging sensitive data
Access control
OAuth overview
Permissions and roles
Regular security audits
Secure data storage and transmission
Continuous monitoring and improvement
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Files and object storage
Databases (intro)
Upload/download patterns
Metadata and naming discipline
Access control mechanisms
Basic CRUD concepts
Modelling discipline
Migration mindset
Conclusion
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Scheduled work
Backoff and retries
Failure reporting
Reliability patterns
Rate limiting
Observability basics
Setting up cron jobs
Advanced cron job techniques
Best practices for cron jobs
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Environment setup
Secrets management
Project structure
Running and testing reliably
Deployment mindset
Keeping changes safe
Rollback habits
Monitoring and alerting
Conclusion
Course requirements.
The requirements necessary for this course include:
Technology
You need a computer/smart device with a decent internet.
Account
No account is required as the lectures are free to view.
Viewing
This course is taught via a blog article format.
Commitment
You will need to dedicate time and effort, at your own pace.
Frequently Asked Questions.
What is Node.js, really?
A server-side JavaScript runtime, not a framework, frameworks like Express run on top of it.
When is Node a good fit?
For I/O-heavy work like APIs, automation, webhooks, and integrations where non-blocking concurrency matters.
Why can Node feel “slow” sometimes?
Long synchronous code blocks the event loop, causing latency spikes and timeouts even if the server is “up”.
What’s the simplest way to keep a Node project maintainable?
Use a clean structure (config, routes, controllers, services), a thin entry file, and centralised error handling.
Why do lockfiles matter?
They pin dependency versions so everyone installs the same tree, reducing “works on my machine” failures.
What’s the difference between devDependencies and dependencies?
Dependencies are required at runtime; devDependencies are tooling (tests, linting). Production installs may omit devDependencies.
How do you prevent Express from crashing on async errors?
Use a central error middleware pattern, consistent error shapes, and ensure async failures flow into the handler (not unhandled).
How should timeouts and retries be handled for integrations?
Always set timeouts, retry only transient failures with backoff, cap attempts, and expose safe fallback states to users.
How do you secure webhooks against spoofing and duplicates?
Verify signatures/shared secrets, reject failed verification, and implement idempotency using provider event IDs with expiry.
How do you make scheduled jobs safe under retries and overlaps?
Design jobs to be idempotent, prevent overlaps for long runs, log outcomes with correlation IDs, and route repeated failures to a dead-letter pattern.
