frontend-security-coder

To prevent XSS when rendering user-generated content, use safe DOM manipulation patterns like secure element creation and text-safe rendering instead of risky HTML injection. Additionally, apply output encoding and validate all user input against an allowlist before updating the DOM.

Content Security Policy (CSP) is a security control that restricts resource loading and script execution in browser-based applications. Configuring CSP alongside Trusted Types and frame protections prevents injection risks, clickjacking, and unauthorized third-party script execution.

Secure token handling and session management require validating authentication flows, using trusted DOM APIs for token storage, and enforcing referrer controls. This protects login sessions and prevents token exposure during navigation and third-party integrations.

The best way to sanitize untrusted content is applying DOM sanitization techniques combined with Subresource Integrity (SRI) controls for third-party widgets. This ensures loaded external resources match expected hashes and prevents malicious content execution.

Implementing safe redirects requires allowlist validation for all redirect URLs and navigation targets. By validating untrusted input against a trusted allowlist, you prevent open redirect vulnerabilities and protect users from malicious navigation flows.