Topic · 31 lessons in 12 series
Networking and HTTP
How data travels: IP, TCP and UDP, DNS, HTTP and HTTPS, load balancers, proxies and WebSockets, with the networking basics every developer should know.
DevOpsWhole series →
- Networking Basics: IP, Ports, TCP/UDP and FirewallsHow a browser request actually finds and reaches your server. The layer Vercel hides completely, and the one you must understand before EC2 makes any sense.16 min
- DNS Deep Dive: From Domain Name to ServerHow a domain name turns into a server address — records, TTL, Route 53, and the one wildcard record that serves unlimited customer subdomains for a multi-tenant SaaS.14 min
- HTTPS, SSL and TLS: Certificates, Let’s Encrypt, ACMWhat the padlock in your address bar actually proves, how a free certificate gets issued, and the exact commands to put HTTPS on your own EC2 server.15 min
- Nginx: Reverse ProxyThe receptionist in front of your app: TLS termination, static files, compression, and why port 3000 never goes public.20 min
System DesignWhole series →
- TCP vs UDP: How Data Actually TravelsThe internet loses, duplicates and reorders packets. TCP promises every byte in order and pays for it in round trips; UDP just sends and lets the app cope. How each works, and how QUIC takes the best of both.8 min
- HTTP & HTTPS Explained: Methods, Status Codes and TLSHTTP is the shared language of the web: a method and URL in, a status code and body out. HTTPS wraps it in TLS so nobody on the path can read or change it. Methods, idempotency, status codes, HTTP/1.1 vs 2 vs 3, and the TLS handshake.12 min
- Load Balancers: L4 vs L7 and Balancing AlgorithmsOne address, many servers, and one of them just crashed at 2 AM. How load balancers spread traffic, L4 vs L7, the balancing algorithms and when each wins, and why a “deep” health check can take everything down at once.10 min
- Reverse Proxy vs API GatewayReverse proxy, load balancer and API gateway get used interchangeably — NGINX is called all three. What each one is actually for, where authentication and rate limiting belong, the Backend-for-Frontend pattern, and when a gateway is overkill.8 min
- Real-Time Apps: Polling, WebSockets and SSEHTTP only lets the client ask. For “new message”, “rider is nearby” or an AI answer streaming in, the server has to push. Short polling, long polling, Server-Sent Events and WebSockets compared — and how to scale millions of open connections.10 min
The Browser ContractWhole series →
- What Happens When You Type a URL (The Full Version)The full trip from pressing Enter to seeing pixels: DNS, TCP, TLS, HTTP, then reading the page and painting it. Caches skip most steps. Every other lesson in this series fits on this map.18 min
- CORS Explained: Same-Origin Policy, Preflights and CredentialsWhy CORS protects the browser and is not a firewall for the server, what makes a preflight request, and why you cannot use a wildcard origin together with credentials.15 min
- HTTP Caching: Cache-Control, ETags and the CDN in BetweenFresh or must-check, no-cache vs no-store, immutable for hashed files, stale-while-revalidate, and what a shared cache must never store.20 min
- HTTP Semantics Interviewers Ask: Methods, Idempotency, Status Codes, RedirectsSafe vs idempotent methods, 401 vs 403, 409, 422 and 429, and the 301/302/307/308 table. All based on the HTTP specification.15 min
Backend in DepthWhole series →
Practical Design ProblemsWhole series →
Full-Stack QuestionsWhole series →
API DesignWhole series →
Node.js From ZeroWhole series →
Next.js App RouterWhole series →
Docker & KubernetesWhole series →
- Volumes, Networks and Running Containers SafelyPersisting data, bind mounts, networks and ports, environment variables and secrets, non-root users and other safety habits.14 min
- Services, Ingress and Networking in KubernetesHow pods find each other, ClusterIP, NodePort and LoadBalancer, DNS names, Ingress, and what a service mesh is for.14 min
Linux & ShellWhole series →
Networking for DevelopersWhole series →
- How the Internet Works: Layers, Packets and AddressesThe layer models, what a packet is, MAC, IP and ports, and following one request from your laptop to a server.13 min
- IP Addresses, Subnets, NAT and RoutingIPv4 and IPv6, CIDR notation worked by hand, private ranges, NAT, routing tables and how a packet finds its way.14 min
- TCP and UDP: Connections, Reliability and CongestionThe three-way handshake, sequence numbers, retransmission, flow and congestion control, UDP, and when each is used. Captured with real packet tools.16 min
- DNS: How Names Become AddressesResolvers, root and authoritative servers, record types, TTL and caching, and debugging DNS with dig.14 min
- HTTP/1.1, HTTP/2 and HTTP/3Requests and responses on the wire, keep-alive, head-of-line blocking, multiplexing, QUIC, and what changes for you as a developer.15 min
- TLS and Certificates: How HTTPS Really WorksThe handshake in plain words, certificates and chains, Let's Encrypt, mTLS, and the errors you will meet.15 min
- Load Balancers, Proxies, CDNs and FirewallsLayer 4 and layer 7 balancing, reverse and forward proxies, CDNs, caching at the edge, and firewalls and security groups.14 min
- WebSockets, Server-Sent Events and Real-Time NetworkingPolling versus long polling, WebSockets, SSE, scaling real-time connections, and a working example of each.14 min
- Debugging Network Problems and Networking Interview Questionscurl, dig, ss, tcpdump and Wireshark basics, a troubleshooting checklist, and interview questions with model answers.16 min