CORS Explained In Depth
Understand Cross-Origin Resource Sharing: simple vs preflight requests, credentials, and the headers that decide whether your browser will let your fetch succeed.
·4 min read · #web#cors#browser
Blog
1745 posts · page 28 of 37
JWT vs Session Authentication
Compare JSON Web Tokens with classic server-side sessions across storage, revocation, scaling, and security so you can choose the right model for your app.
·4 min read · #web#auth#jwt
Web Performance: Core Web Vitals Guide
A practical guide to Core Web Vitals: LCP, INP, and CLS. How they are measured, what hurts them, and concrete fixes that move the numbers.
·5 min read · #web#performance#core-web-vitals
Progressive Web Apps: An Introduction
Learn what makes an app a PWA: service workers, manifests, install prompts, and offline-first strategies that turn a website into something that feels native.
·4 min read · #web#pwa#service-worker
Service Workers: A Deep Dive
How service workers actually run: lifecycle, fetch interception, caching strategies, updates, and the operational habits that keep them from breaking your site.
·4 min read · #web#service-workers#pwa
WebSockets vs Server-Sent Events
How WebSockets and SSE differ in transport, direction, reconnection, and operations, with guidance on when each one is the right pick for real-time web apps.
·4 min read · #web#websockets#sse
Property-Based Testing: An Introduction
Stop writing one example per test. Property-based testing generates inputs for you and finds the edge cases you would never think to write.
·5 min read · #testing#property-based#fuzzing
Contract Tests Explained: Catching Integration Bugs Early
Understand consumer-driven contract testing, how it differs from integration tests, and how tools like Pact prevent breaking API changes between services.
·4 min read · #testing#contract-testing#pact
Test Coverage Metrics and Their Pitfalls
Line, branch, and mutation coverage explained. Learn what each metric tells you, what it hides, and how to use coverage without gaming it.
·4 min read · #testing#coverage#metrics
End-to-End Testing with Playwright: A Practical Tutorial
Learn how to write reliable end-to-end tests with Playwright, including selectors, fixtures, auto-waiting, and patterns that avoid flakiness.
·4 min read · #testing#playwright#e2e
Flaky Tests and How to Fix Them
Diagnose and eliminate flaky tests caused by timing, ordering, shared state, and the network. Build a culture that stops flakes at the source.
·4 min read · #testing#flaky#ci
Load Testing with k6
A practical introduction to k6 for load testing HTTP services. Covers scripting, stages, thresholds, and how to read the results without fooling yourself.
·4 min read · #testing#load-testing#k6
Mocking and Stubbing Strategies in Tests
Pick the right test double for the job. Compare mocks, stubs, fakes, and spies, and learn when to skip them entirely.
·4 min read · #testing#mocks#stubs
Testing Pyramid: Unit, Integration, E2E
What the testing pyramid actually means in modern apps, when to deviate, and how to keep each layer giving you the value it is supposed to.
·5 min read · #testing#unit#integration
Snapshot Tests Explained
Learn how snapshot tests work, when they shine, and how to keep them maintainable instead of letting them rot into noise.
·3 min read · #testing#snapshots#jest
The Test Data Builder Pattern: Readable Fixtures at Scale
Stop drowning in fixture noise. Learn the Test Data Builder pattern to create clear, intention-revealing test data that survives schema changes.
·4 min read · #testing#patterns#fixtures
Vitest Tutorial
A practical guide to Vitest, the testing framework built for modern JavaScript projects. Setup, syntax, mocking, coverage, and how it differs from Jest in ways that matter.
·4 min read · #testing#vitest#javascript
TypeScript Conditional Types Tutorial
Learn conditional types in TypeScript: distribution, infer, and how to build expressive utility types that adapt to the input shape.
·4 min read · #typescript#conditional-types#infer
TypeScript Enums vs Union Literals
Compare TypeScript enums with string union literals. Learn the trade-offs in runtime cost, exhaustiveness, ergonomics, and when each is the right choice.
·5 min read · #typescript#enums#union-types
TypeScript Generics with React
A practical guide to using TypeScript generics in React components, hooks, and props for safer, more reusable building blocks.
·4 min read · #typescript#generics#react
TypeScript infer Keyword Explained
Master the infer keyword in TypeScript conditional types. Learn how to extract parts of complex types, build utility helpers, and write expressive generics.
·5 min read · #typescript#infer#conditional-types
TypeScript Mapped Types Deep Dive
A practical tour of mapped types in TypeScript, including key remapping, modifiers, and patterns that build powerful generic utilities.
·4 min read · #typescript#mapped-types#generics
TypeScript Narrowing and Control Flow Analysis
Learn how TypeScript narrows types through control flow, using typeof, instanceof, in, and discriminated unions to write safer code.
·4 min read · #typescript#narrowing#control-flow
TypeScript Recursive Types Tutorial
Build recursive types in TypeScript: deep readonly, JSON, paths, and tuple manipulation. Learn how to write recursion that the compiler can actually evaluate.
·5 min read · #typescript#recursive-types#generics
TypeScript Strict Mode and tsconfig Tips
Understand what strict mode actually turns on, which extra flags are worth enabling, and how to adopt strictness incrementally.
·3 min read · #typescript#tsconfig#strict
TypeScript Type Guards Deep Dive
Master TypeScript type guards: typeof, instanceof, discriminated unions, user-defined predicates, and assertion functions. Narrow types safely and idiomatically.
·5 min read · #typescript#type-guards#narrowing
TypeScript Utility Types Cheatsheet
A practical reference for TypeScript utility types: Partial, Pick, Omit, Record, Readonly, ReturnType, and a dozen more with real examples.
·5 min read · #typescript#types#cheatsheet
TypeScript with Zod Validation
Use Zod with TypeScript to validate runtime data and infer types from a single source of truth. Cover schemas, parsing, transforms, and error handling.
·5 min read · #typescript#zod#validation
AI Agents and Tool Use Patterns
Practical patterns for building AI agents that use tools well: tool definitions, loops, planning, parallel calls, error handling, and how to keep agents from going off the rails.
·5 min read · #ai#agents#tool-use
Attention Mechanism Intuition
Build a clear intuition for self-attention: queries, keys, values, softmax weights, and why this single operation lets transformers handle language so well.
·5 min read · #ai#attention#transformers
Embeddings Explained for Developers
What embeddings are, why they work, how to use them for search and clustering, how to pick a model, and the practical pitfalls that bite first-time users.
·5 min read · #ai#embeddings#search
Fine-Tuning LLMs: When and How
A practical guide to deciding whether to fine-tune an LLM, choosing between full fine-tuning, LoRA, and instruction tuning, and avoiding the common pitfalls that waste a budget.
·5 min read · #ai#fine-tuning#lora
LangChain vs LlamaIndex
A practical comparison of LangChain and LlamaIndex: what each framework is good at, where they overlap, and how to pick one (or skip both) for your LLM application.
·5 min read · #ai#langchain#llamaindex
Prompt Engineering Techniques That Work
A grounded tour of prompt engineering techniques: clear instructions, structured output, few-shot examples, chain-of-thought, role prompts, and evaluation habits that keep prompts honest.
·5 min read · #ai#prompting#llm
RAG Retrieval Strategies
Practical retrieval strategies for RAG: chunking, hybrid search, reranking, query rewriting, metadata filtering, and evaluation patterns that actually move the needle.
·5 min read · #ai#rag#retrieval
Transformers Architecture Explained
Walk through the transformer architecture that powers modern LLMs: tokens, embeddings, self-attention, multi-head attention, feed-forward layers, residuals, and the path from input to output.
·5 min read · #ai#transformers#llm
Vector Databases Compared
A grounded comparison of vector databases for RAG and semantic search: pgvector, Pinecone, Weaviate, Qdrant, Milvus, and Chroma, with guidance on when each shines.
·5 min read · #ai#vector-database#rag
The FAANG Interview Process Explained, Stage by Stage
A walkthrough of the FAANG interview funnel: recruiter screen, phone screen, onsite loop, debrief, and offer. Learn what each stage tests and how to prepare for each one.
·6 min read · #career#interviews#faang
How to Grind LeetCode Effectively: Patterns Over Volume
Stop doing 500 random problems. Use spaced repetition, study patterns instead of volume, and run weekly mock interviews to make every LeetCode hour count.
·5 min read · #career#leetcode#interview-prep
How to Write a Cover Letter as a Software Engineer
A practical template for engineering cover letters that recruiters actually read. Includes structure, opening hooks, what to cut, and a worked example for a backend role.
·6 min read · #career#cover-letter#job-search
SDE Roadmap Overview: 10 Phases from Zero to Senior
A high-level tour of the 10-phase SDE roadmap on Codeloom. Learn what each phase covers, why the order matters, and how to use the full plan to guide your study.
·5 min read · #career#roadmap#sde
AWS IAM Roles and Policies: A Practical Tutorial
Learn how AWS IAM roles, trust policies, and permissions policies work together. Build a small role from scratch and assume it from another account.
·5 min read · #devops#aws#iam
Docker Compose Tutorial: Run Multi-Service Apps Locally
A practical Docker Compose tutorial. Define services, networks, and volumes in one YAML file, then start and stop a full local stack with a single command.
·4 min read · #devops#docker#compose
Docker Volumes Explained: Persisting Data the Right Way
Learn how Docker volumes keep your data alive between container restarts. Compare bind mounts, named volumes, and tmpfs, and see when to use each in real projects.
·4 min read · #devops#docker#volumes
Git Branching Strategies: Trunk vs Gitflow vs GitHub Flow
Compare trunk-based development, gitflow, and GitHub flow. Learn when each strategy fits, how they affect release cadence, and which commands to actually use day to day.
·5 min read · #devops#git#branching
GitHub Actions Secrets Management: A Practical Guide
Learn how to store, scope, and rotate secrets in GitHub Actions. Cover repository, environment, and organization secrets, plus OIDC for cloud access without static keys.
·5 min read · #devops#github-actions#secrets
Kubernetes Deployments vs StatefulSets: When to Use Each
Understand the real differences between Deployments and StatefulSets in Kubernetes. Learn which workloads belong in each, with concrete YAML and rollout behavior.
·4 min read · #devops#kubernetes#workloads
Kubernetes Services Explained: ClusterIP, NodePort, LoadBalancer
A clear guide to Kubernetes Services. Learn what ClusterIP, NodePort, LoadBalancer, and headless Services do, and when to use each in real clusters.
·4 min read · #devops#kubernetes#networking