Input validation matters because attacks like injection and cross-site scripting come from trusting user-supplied data. Treat all input as untrusted, and never build database queries or pages by pasting raw input in. Frameworks handle much of this if you use them properly.
Security is ongoing, not a launch checkbox. New vulnerabilities appear, dependencies need patching, and access should be reviewed. Building on a well-maintained framework, keeping things updated, and following established practices covers the large majority of real-world risk.
Updated July 2026
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