Perisai Web Scanner is an automated security scanning tool that analyzes websites for known vulnerabilities and security misconfigurations. The scanner examines web applications to identify vulnerable versions of JavaScript libraries and third-party open-source dependencies that could pose cybersecurity threats. It performs in-depth analysis of each file found on the website and assigns risk scores based on detected vulnerabilities. The tool evaluates security based on two core metrics: 1) Detection of vulnerable JavaScript library versions that pose potential security threats, and 2) Analysis of HTTP security headers to identify which headers are properly configured and which recommended headers are missing. The scanner provides a grading system with A+ being the highest achievable security score. The web scanner operates as an early warning system for website security, allowing organizations to identify and address security weaknesses before they can be exploited. It searches for software vulnerabilities, misconfigurations, and dependency issues across the entire website infrastructure. The tool is accessible through a web interface where users can input their domain (supporting both HTTP and HTTPS protocols) to initiate security checks.