Software security fundamentals: threats, vulnerabilities, and defenses. Build systems that protect data and users from attacks.

Performance testing fundamentals: load testing, stress testing, and metrics. Build systems that handle real traffic and find bottlenecks before users.

Master web accessibility fundamentals: semantic HTML, keyboard navigation, ARIA, and WCAG testing. Build inclusive interfaces that work for all users.

Learn color and contrast fundamentals: build readable interfaces, ensure accessibility, and create effective visual designs. Understand color theory, contrast ratios, WCAG standards, and color accessibility.

Understanding why software testing matters and how to build confidence in your code. Learn the core principles that separate effective testing from test coverage theater.

Step-by-step guide showing how to add tests to legacy code without tests. Learn to identify what to test, write your first tests, and gradually improve coverage.

Step-by-step guide to writing unit tests that verify behavior, catch bugs early, and make refactoring safe. Learn the workflow, patterns, and best practices.

Comprehensive testing checklist covering unit tests, integration tests, test design, and quality gates. Use this reference to ensure your tests are effective and maintainable.

Master software product development fundamentals: user research, MVP validation, feature development, iteration, and metrics. Build products that solve real problems.

Learn frontend engineering fundamentals: build working interfaces, write maintainable code, optimize performance, and ensure accessibility.