Programación

WebSocket is the protocol that keeps a connection open between browser and server so both sides can send data at any time. This article explains the handshake, frame structure, and how to implement it step by step with Node.js.

The QUIC protocol runs over UDP and eliminates the slow handshake of separate TCP plus TLS negotiations, letting HTTP/3 open connections in a single round trip or even zero. This guide explains how it works internally, how to test it with curl and nginx, and when it makes sense over HTTP/2.

CORS is the policy that decides whether the browser hands over an API response to a script running on another domain. This guide explains the preflight mechanism, the exact headers you need, and the most common configuration mistakes.

GraphQL is a query language that lets the client request exactly the data it needs, without over-fetching or chaining multiple calls. This guide explains how it works internally, with code examples and an honest comparison with REST.

A JWT token lets a server confirm who you are without querying the database again on every request. This guide explains its structure, how to sign it with Node.js, and its real security risks.

Regex engines aren’t magic: they parse the pattern, build an automaton, and run it against the text. This article explains how they work internally, why some are vulnerable to ReDoS, and when it makes sense to switch to an automaton-based engine like RE2.