What is a cron job? How cron works and how to schedule tasksWhat is a cron job? Learn how cron and crontab work, the five-field schedule syntax with examples, common use cases, and modern alternatives like systemd timers and managed schedulers.What is unit testing? How to write, structure, and run unit testsUnit testing is the practice of testing the smallest testable parts of a program — functions, methods, or classes — in isolation. Learn what a unit test is, the arrange-act-assert structure, test doubles and mocking, the testing pyramid, and best practices for writing good unit tests.CI/CD Explained: Continuous Integration, Delivery & DeploymentCI/CD automates the path from code commit to production: continuous integration builds and tests every change, continuous delivery keeps releases ready, continuous deployment ships them automatically.How to set up CI/CD with GitHub ActionsSet up a CI/CD pipeline with GitHub Actions: create your first workflow, configure triggers, build and test your code on runners, use actions and secrets, and deploy automatically — open-license sources.Infrastructure as Code: What it is and why it changes everythingInfrastructure as Code replaces manual server setup with definition files you version, test, and deploy like software. Learn the declarative vs imperative split, the key benefits, and which tools are available.What is a webhook? How webhooks work and how to secure themA webhook is a user-defined HTTP callback: one service sends an HTTP request to a URL you control when an event happens. Learn how they work, how they differ from polling and regular APIs, and how to verify signatures and handle retries safely. 