What is a database transaction? ACID properties explainedA database transaction bundles several operations into one all-or-nothing unit. This guide explains transactions, the ACID properties (atomicity, consistency, isolation, durability), and isolation levels.GraphQL vs gRPC: which API technology should you choose?GraphQL and gRPC are two modern ways to build APIs. GraphQL lets clients query exactly the fields they need over a single HTTP endpoint; gRPC calls typed remote methods over HTTP/2 with binary Protocol Buffers. Compare the trade-offs and learn when to choose each.How to handle errors in Node.js: try/catch, error-first callbacks, promises, and event emittersNode.js errors come in several asynchronous styles, and each has its own correct way to be caught. This guide explains try/catch for synchronous code, error-first callbacks, promise rejection handling, and the 'error' event for streams and event emitters.REST vs gRPC: which API style should you choose?REST and gRPC are two ways to build APIs. REST uses HTTP and JSON with universal browser support; gRPC uses HTTP/2 and Protocol Buffers for binary efficiency and code-generated stubs. Compare the trade-offs and learn when to choose each.What is an API Gateway? A practical guide for developersAn API gateway is a single front door for all client requests to your back-end services. This guide explains what an API gateway does, the problems it solves, common patterns, and how to choose one.What is GraphQL? How it works and when you should use itGraphQL is an open-source query language for APIs that lets clients request exactly the data they need. This guide explains how GraphQL works, its type system, queries and mutations, and how it compares to REST.What are Protocol Buffers? How protobuf works and when to use itProtocol Buffers (protobuf) is Google's language-neutral, platform-neutral data serialization format. Define your data once in a .proto file, compile it, and get fast, compact binary output. Learn how protobuf works and when it outperforms JSON.How to implement rate limiting in Node.js: algorithms and practical examplesRate limiting protects Node.js APIs from abuse and overload. This guide explains fixed window, sliding window, and token bucket algorithms, shows how to add rate limiting to an Express API, and how to test it.How to build a REST API with Node.js and ExpressLearn to create a production-ready RESTful API using Node.js and Express: setup, routing, middleware, environment variables, error handling, and deployment best practices — with a practical CRUD example for managing resources.REST vs GraphQL: which API style should you choose?REST and GraphQL are two ways to build web APIs. REST uses fixed endpoints and HTTP methods; GraphQL uses a single endpoint where clients query exactly the fields they need. Compare the trade-offs and learn how to choose.What is database normalization? 1NF, 2NF, 3NF, and BCNF explainedDatabase normalization is the process of structuring a relational database according to a series of normal forms to reduce data redundancy and improve data integrity. This guide explains why normalization matters, walks through 1NF, 2NF, 3NF, BCNF, 4NF, and 5NF with worked examples, and when denormalization is the right trade-off.What is a SQL query? How SELECT, JOIN and aggregation workA SQL query is a declarative statement that asks a relational database for data. This guide explains the SELECT statement, WHERE filtering, JOIN across tables, GROUP BY aggregation, and how to read a query plan. 