All Topics

Backend · 20

Real-Time Systems

WebSockets vs SSE. Scaling stateful connections. When HTTP isn't enough.

10 min read Backend · 26

Full-Text Search

Inverted indexes, BM25, Elasticsearch — why LIKE queries don't scale.

12 min read

Backend · 07

Middleware

The chain of responsibility. Order matters. Single-responsibility middleware.

9 min read Backend · 08

Request Context

AsyncLocalStorage, contextvars, context.Context — sharing state down the call tree.

7 min read Backend · 09

Handlers, Controllers & Services

Layered architecture. Why your service layer should never know about HTTP.

10 min read Backend · 11

RESTful API Design

Resources are nouns. Pagination strategies. Response shape standards. HATEOAS.

15 min read Backend · 28

Monolith vs Microservices

When to split a system, the modular monolith middle ground, and the distributed monolith trap.

13 min read Backend · 33

API Gateway, Reverse Proxy & BFF

What sits in front of your services. Nginx, load balancers, the BFF pattern — the edge of your system.

12 min read Backend · 34

Beyond REST — gRPC & GraphQL

Two alternatives to REST and when each one earns its place. Same problem, different trade-offs.

13 min read Backend · 38

Multi-Tenancy

Building SaaS that serves many customers from one system — without leaking their data into each other.

12 min read DevOps · 05

Classes and Objects

The blueprint and the thing built from it. Constructors, fields, methods, the static keyword, and what `new` actually does at the JVM level.

14 min read DevOps · 06

The Four Pillars of OOP

Encapsulation, inheritance, polymorphism, abstraction — but with real examples, not the textbook version everyone has to memorise then forget.

15 min read DevOps · 07

Abstract Classes vs Interfaces

The most-asked Java interview question. The real differences, when to pick each, and how default methods in Java 8+ blurred the lines.

14 min read DevOps · 09

Access Modifiers and Packages

public, protected, private, and the package-private one nobody knows the name of. What each does, when to use them, and how packages organise the chaos.

10 min read DevOps · 11

Generics and Type Erasure

How generics actually work — at compile time, anyway. Type erasure, bounded types, wildcards, and the weird things they enable and forbid.

14 min read DevOps · 15

Inner Classes and Anonymous Classes

Classes inside classes. Static nested, inner, local, anonymous, lambdas — the spectrum from explicit to invisible, and when each is the right tool.

11 min read

Backend · 13

Task Queues & Background Jobs

Why some work doesn't belong in the request cycle. Retries, DLQs, idempotency.

11 min read Backend · 29

Event-Driven Architecture

Events vs commands, pub/sub patterns, Kafka, event sourcing — decoupling services with messages.

14 min read

DevOps · 06

Continuous Integration

Automated testing on every change. The shortest feedback loop in software engineering.

12 min read DevOps · 07

Continuous Delivery & Deployment

From green build to running in production. Pipelines, environments, and the difference between delivery and deployment.

13 min read DevOps · 08

GitHub Actions in Depth

Workflows, matrix builds, reusable actions, OIDC, and the patterns that scale to large orgs.

14 min read DevOps · 09

Build Optimization

Caching, parallelism, monorepo strategies. How to keep CI under 5 minutes as your codebase grows.

11 min read

DevOps · 16

Cloud Computing Models

IaaS, PaaS, SaaS, serverless. Why the cloud changed everything and what it actually offers.

11 min read DevOps · 17

AWS Core Services

EC2, S3, RDS, Lambda, IAM — the building blocks behind most modern infrastructure.

17 min read DevOps · 18

GCP Core Services

Compute Engine, GCS, Cloud SQL, Cloud Run, IAM — Google Cloud essentials and how it differs from AWS.

14 min read DevOps · 19

Cloud Networking

VPCs, peering, transit gateways, private connectivity — the network plumbing that ties cloud workloads together.

12 min read

DevOps · 10

Docker — Containers from First Principles

Images, layers, networking, multi-stage builds. The technology that made 'works on my machine' obsolete.

15 min read DevOps · 11

Container Image Security

Vulnerabilities, supply chain attacks, image signing — keeping your containers from becoming the entry point.

11 min read DevOps · 12

Docker Compose for Local Development

Define your whole stack in one file. The fastest way to onboard new engineers.

9 min read

Backend · 04

Serialization & Deserialization

JSON vs Protobuf. Schema validation. The gotchas that bite in production.

11 min read Backend · 06

Validation & Transformation

Three layers of validation. Actionable error messages. Trust nothing, sanitize early.

8 min read Backend · 10

Databases

ACID, indexing, N+1, migrations, connection pooling — the database fundamentals.

22 min read Backend · 30

File Uploads & Object Storage

S3, presigned URLs, multipart uploads, and how to handle files without your server becoming the bottleneck.

12 min read Backend · 35

Database Replication & Sharding

How databases scale beyond one machine. Read replicas, leader/follower, sharding, and the trade-offs.

13 min read DevOps · 04

Strings Deep Dive

Why == lies. The String Pool. StringBuilder vs StringBuffer vs string concatenation in a loop. The 1000-object trap.

13 min read DevOps · 12

Collections Framework

List, Set, Map, Queue — the interfaces and the implementations. When to pick which. How HashMap actually works inside.

18 min read DevOps · 14

Enums

Type-safe constants. Methods on enum values. The trick of using an enum as a singleton. Java's enum is more powerful than most people realise.

10 min read

Backend · 01

What is a Backend?

The mental model. HTTP request loop. Why first principles beat framework knowledge.

10 min read Backend · 02

HTTP Protocol

Anatomy of requests, methods, status codes, and the headers you must know.

12 min read Backend · 03

Routing

Matching method + path to handlers. Radix trees, parameters, versioning.

9 min read Backend · 25

How a Request Travels the Network

DNS, packets, hops — what actually happens between typing a URL and seeing a response.

11 min read Backend · 27

Distributed Systems & CAP

The 8 fallacies, CAP theorem, eventual consistency — what changes when you add a second computer.

14 min read Backend · 32

Money, Time & Identity

The three things that bite every backend engineer eventually. Cents, UTC, UUIDs — get them right early.

10 min read Backend · 39

Internationalization (i18n) & Localization

Building software that works in every language, region, and writing system — from day one.

11 min read DevOps · 01

What is DevOps, Really?

Beyond the buzzwords. The cultural shift that turned operations from a separate team into shared responsibility.

12 min read DevOps · 02

Linux Fundamentals for DevOps

The terminal, processes, permissions, and signals — every cloud server you'll ever touch runs on this.

16 min read DevOps · 03

Networking Essentials

IPs, ports, DNS, VPCs, firewalls — the network primitives every cloud engineer needs in their bones.

15 min read DevOps · 04

Shell Scripting & Automation

Bash scripting from variables to traps. The glue that holds DevOps automation together.

14 min read DevOps · 01

What Java Actually Is (And Why It Survived)

Origin, evolution, and the real reason Java is still everywhere in 2026 — even after every other language tried to kill it.

11 min read DevOps · 02

The JVM, JRE, JDK — What's Actually Happening

From .java to running bytes. Class loaders, runtime memory areas, JIT, and the garbage collector — the whole machine demystified.

18 min read DevOps · 03

Variables, Primitives, and the Memory Model

Stack vs heap. Primitives vs references. Autoboxing traps. The memory model that shapes every line of Java you'll write.

14 min read DevOps · 08

The Object Class — equals, hashCode, toString

Every Java class secretly inherits from Object. These three methods determine whether your objects work correctly in collections, comparisons, and logs.

15 min read DevOps · 13

Control Flow and Operators

if, while, for, switch — plus the modern switch expression and pattern matching. Operators and the precedence rules nobody memorises.

9 min read

DevOps · 20

Terraform — Infrastructure as Code

Declarative infrastructure. Providers, state, modules — and why your cloud should be defined by code review.

16 min read DevOps · 21

Pulumi & CDK — Code-First IaC

When real programming languages beat Terraform's HCL. Tradeoffs, when to use each.

9 min read DevOps · 22

Configuration Management — Ansible

Configuring servers idempotently. When and why you still need this in a containerized world.

9 min read

Backend · 24

Webhooks & OpenAPI

Verify every webhook signature. Why OpenAPI is documentation that compiles.

9 min read Backend · 36

Notifications — Email, SMS & Push

How to send messages reliably at scale. Provider patterns, deliverability, unsubscribes, and async always.

11 min read Backend · 37

Payments & Financial Systems

Stripe-style integrations done safely. Webhooks, idempotency, reconciliation — and never storing card numbers.

13 min read

DevOps · 34

GitOps with ArgoCD & Flux

Git as the source of truth for infrastructure. Continuous reconciliation, audit trails, declarative everything.

10 min read DevOps · 35

Platform Engineering

Building internal developer platforms — golden paths, self-service, and the team that scales engineering.

11 min read DevOps · 36

Edge Computing & CDNs

Cloudflare, edge functions, and pushing compute close to users. The new layer in the stack.

9 min read DevOps · 16

Lambdas and Functional Interfaces

The Java 8 feature that changed everything. Method references, the standard functional interfaces, and the patterns that replaced 80% of inner-class boilerplate.

12 min read DevOps · 17

Streams API

Filter, map, reduce — Java's functional pipeline for collections. When streams are clearer than loops, and when they aren't.

14 min read DevOps · 20

Modern Java: Records, Sealed Classes, Pattern Matching

What's new in Java 16-21. The features that made the language feel current again. Records, sealed types, pattern matching, var, text blocks.

12 min read

DevOps · 23

Monitoring with Prometheus & Grafana

Metrics that matter, dashboards that don't lie, and alerts that fire when (and only when) things break.

13 min read DevOps · 24

Logging at Scale

Structured logs, ELK, Loki, and the discipline of logging things you'll actually want at 3 AM.

11 min read DevOps · 25

Distributed Tracing

OpenTelemetry, Jaeger, Tempo — seeing how a single request flows across many services.

11 min read DevOps · 26

SRE Principles

SLIs, SLOs, error budgets — Google's framework for reliability without sacrificing velocity.

12 min read

Backend · 15

Logging, Monitoring & Observability

Logs, metrics, traces — the three pillars. Correlation IDs. What to alert on.

16 min read Backend · 22

12-Factor App & Config Management

Why config lives in env vars. Validating at startup. Feature flags done right.

8 min read Backend · 23

DevOps for Backend Engineers

Docker basics, Kubernetes essentials, the CI/CD pipeline that catches bugs early.

13 min read DevOps · 30

Deployment Strategies in Practice

Blue-green, canary, feature flags — picking the right strategy for the risk and the team.

10 min read DevOps · 31

Incident Response

When things break: how good teams handle the first 60 minutes and the next 60 days.

11 min read DevOps · 32

Disaster Recovery & Backups

RPO, RTO, restore drills — preparing for the day a region disappears.

10 min read DevOps · 33

Cost Optimization (FinOps)

Cloud bills get expensive. The practices and tools to keep spend predictable and right-sized.

10 min read DevOps · 19

Build Tools and Project Structure

Maven, Gradle, the standard project layout. Dependency management, build lifecycles, and which tool to pick in 2026.

10 min read

DevOps · 13

Kubernetes Fundamentals

Pods, Deployments, Services — the mental model for the system that runs most modern infrastructure.

16 min read DevOps · 14

Kubernetes in Practice

Helm, autoscaling, persistent volumes, RBAC — what you actually need to run production K8s.

14 min read DevOps · 15

Service Mesh — When You Need One

Istio, Linkerd, Cilium — what they actually do, and when adding one helps vs hurts.

10 min read

Backend · 12

Caching

Cache-aside. TTL vs event invalidation. Stampedes, poisoning, HTTP caching.

13 min read Backend · 18

Scaling & Performance

Vertical vs horizontal. Load balancing. Read replicas. The optimization checklist.

14 min read Backend · 19

Concurrency & Async

Event loop, goroutines, race conditions. Why one thread can serve 10k requests.

11 min read DevOps · 18

Concurrency and Multithreading

Threads, the memory model, synchronization, volatile, atomics, ExecutorService, and why concurrency is the hardest topic in Java.

18 min read

Backend · 21

Testing & Code Quality

The testing pyramid. Mocks vs fakes. SOLID, DRY, YAGNI — without dogma.

12 min read

Backend · 14

Error Handling

Operational vs programmer errors. Retries, circuit breakers, async pitfalls.

14 min read Backend · 17

Graceful Shutdown

SIGTERM. Liveness vs readiness. Zero-downtime deploys in Kubernetes.

7 min read Backend · 31

Idempotency & Distributed Patterns

Idempotency keys, sagas, the outbox pattern — making distributed work safe in the face of retries and partial failures.

13 min read DevOps · 10

Exception Handling

Checked vs unchecked. try/catch/finally. try-with-resources. The dogmatic rules everyone learns and the pragmatic ones senior developers actually follow.

16 min read

Backend · 05

Authentication & Authorization

Sessions vs JWTs. OAuth flows. RBAC done right. Why bcrypt is non-negotiable.

18 min read Backend · 16

Security

OWASP Top 10. SQL injection. Rate limiting. CORS. Secret management.

15 min read DevOps · 27

DevSecOps — Shifting Security Left

Building security into every step instead of bolting it on at the end.

11 min read DevOps · 28

Secrets Management

Vault, KMS, sealed secrets — keeping passwords and API keys out of Git and out of trouble.

10 min read DevOps · 29

Cloud Security Posture

Least privilege, network policies, security baselines — defense in depth for cloud workloads.

11 min read

DevOps · 05

Git — Beyond Add, Commit, Push

Branches, rebases, conflict resolution, and the workflows real teams use.

14 min read