Top Free Website Security Checkers for 2025

Hello there! As part of the content team here at RobotAlp, I spend a good chunk of my time exploring the landscape of tools that help keep our digital world safer and more reliable. Website security is a topic that’s always high on the agenda, and for a good reason. While there are many powerful commercial security suites available, a recurring question I encounter from our community and fellow web enthusiasts is about accessible, free options for a first line of defense. It’s a crucial point – robust security shouldn't only be for those with deep pockets.

So, I embarked on a research mission, leveraging insights from our internal analyses including data compiled with the help of advanced language models like "NotebookLLM" and surveying the current offerings. The aim was to curate a practical list of free website security checkers that are actively maintained in 2025 and can genuinely assist you in performing initial vulnerability scans. This guide isn't about replacing comprehensive penetration testing but empowering you with no-cost tools for regular security health checks.

Before we dive into the specific tools, it's helpful to understand a common category they belong to: Dynamic Application Security Testing (DAST) tools. Unlike SAST (Static Application Security Testing) tools that analyze your application's source code, DAST tools interact with your live, running web application from an external perspective. They simulate how an attacker might probe your site, actively searching for common vulnerabilities like Cross-Site Scripting (XSS), SQL Injection, insecure server configurations, command injection, and path traversal. Essentially, they are automated scouts actively seeking out potential weaknesses.

Incorporating regular scans, even with free tools, into your website maintenance routine offers several key advantages:

• Proactive Vulnerability Detection: Identify and address common, easily exploitable vulnerabilities before malicious actors find them.
• Enhanced Security Awareness: Gain a better understanding of potential weaknesses specific to your web applications.
• Cost-Effective Initial Assessment: A crucial starting point for bolstering your security posture without immediate financial outlay.
• Building a Security Baseline: Establish a foundational understanding of your site’s current security health.

It's always recommended to consult resources from organizations like OWASP (Open Web Application Security Project). While OWASP doesn't endorse specific vendors or scanning tools, their projects, such as the widely recognized OWASP Top 10, provide invaluable information on the most critical web application security risks, many of which these free tools can help detect.

Top Free & Actively Maintained DAST Tools for 2025

Our research, focusing on tools that are free, actively maintained as of 2025, and directly usable for web/DAST purposes, has highlighted these leading contenders:

1. Nikto / Nikto Online

• Type: Open Source (Nikto) / Free SaaS (Nikto Online)
• Platform: Unix/Linux (Nikto); Web-based (Nikto Online)
• Summary: A well-known command-line web server scanner, Nikto identifies known vulnerabilities, outdated server software, and specific version issues. Nikto Online offers a quick, browser-based version for some of these checks without needing an account.
• Website: Nikto (cirt.net)

2. OWASP Zed Attack Proxy (ZAP)

• Type: Open Source (Apache-2.0 License)
• Platform: Windows, Linux, macOS
• Summary: Actively maintained by OWASP, ZAP is an extremely popular and powerful free security tool. It functions as an intercepting proxy and offers both automated scanning and extensive manual testing capabilities.
• Website: OWASP ZAP

3. OpenVAS (Greenbone Vulnerability Manager - GVM)

• Type: Open Source
• Platform: Linux
• Summary: The open-source edition from Greenbone,GVM (formerly OpenVAS) is a full-featured network and web vulnerability scanner. It uses a comprehensive, regularly updated feed of Network Vulnerability Tests (NVTs).

GVM (formerly OpenVAS) is a full-featured network and web vulnerability scanner. It uses a comprehensive, regularly updated feed of Network Vulnerability Tests (NVTs).

4. Nuclei

• Type: Open Source
• Platform: Windows, Unix/Linux, macOS
• Summary: Nuclei is renowned for its speed and flexibility, leveraging YAML-based templates for fast, customizable DAST scans. It's well-suited for CI/CD integration.
• Website: Project Discovery - Nuc

5. Vega

• Type: Open Source
• Platform: Windows, Linux, macOS
• Summary: Vega provides a graphical user interface (GUI) to automate tests for common web vulnerabilities like XSS, SQL injection, and CSRF. Its GUI can make it more approachable for some users.
• Website: (Typically found via Subgraph anada.gov, but ensure to verify the official active source)

6. Wapiti

• Type: Open Source
• Platform: Windows, Unix/Linux, macOS
• Summary: Wapiti performs black-box scans by crawling web pages and injecting payloads to find vulnerabilities such as XSS, SQLi, and file system access issues.
• Website: Wapiti Official Site (wapiti.sourceforge.net)

7. HostedScan.com

• Type: Free SaaS
• Platform: Web-based
• Summary: An online service offering unlimited free scans (for its free tier) without requiring account creation. It provides a simple and quick option for network and web vulnerability scanning.

8. ZeroThreat

• Type: Free SaaS
• Platform: Web-based
• Summary: Focuses on DAST capabilities for modern web applications and APIs, also usable without an account.
• Note: Users can search for "ZeroThreat DAST" to find its current portal.

9. purpleteam

• Type: Open Source (GNU-AGPL v3)
• Platform: CLI & SaaS
• Summary: OWASP-supported tool that can be used both via command-line interface or as a SaaS solution for web application vulnerability scanning.
• Website: (Search for "OWASP PurpleTeam" or its GitHub repository)

10. Arachni

• Type: Open Source
• Platform: Windows, Linux, macOS
• Summary: A feature-rich, modular framework aimed at helping penetration testers and administrators evaluate the security of web applications. Mostly free for many use cases.
• Website: Arachni Scanner

11. OSTE Meta Scanner

• Type: Open Source
• Platform: Linux
• Summary: This tool acts as a meta-scanner, orchestrating and combining the results from multiple DAST engines like Nikto, ZAP, Nuclei, and Wapiti.
• Website: (Typically found on GitHub, search for "OSTE Meta Scanner")

These 11 tools [Vega source needs careful checking as original Subgraph links can be unstable] represent a strong starting point for free, actively maintained DAST scanning in 2025, as highlighted in our source research.

The initial research also mentioned a few other well-known open-source tools. While their active maintenance status for 2025 wasn't as explicitly confirmed in the source documents as the ones above, they have historically been significant in the security space:

• Skipfish: A high-speed, reconnaissance-focused web application security scanner from Google. It performs dictionary-based probes and creates interactive sitemaps.
• Website: (Typically found via search for "Skipfish Google")
• w3af (Web Application Attack and Audit Framework): A Python-based framework with a plugin architecture to find andexploit web application vulnerabilities. Offers both GUI and CLI.
• Website: w3af.org
• SQLmap: A highly specialized open-source penetration testing tool that automates the process of detecting and exploiting SQL injection flaws and taking over database servers.
• Website: sqlmap.org

For quick checks on specific security aspects, these free online services are invaluable:

• Security Headers: Developed by Scott Helme, this tool analyzes your HTTP response headers and grades them based on security best practices (HSTS, CSP, X-Frame-Options, etc.).
• Qualys SSL Labs SSL Test: Provides a deep analysis of your SSL/TLS server configuration, highlighting potential weaknesses and compatibility issues.

Important Considerations When Using Free Tools

While the free tools listed offer significant capabilities, it's essential to approach their use with the right mindset:

• No Silver Bullet: No single automated tool can uncover every vulnerability. A defense-in-depth strategy often involves using multiple tools and techniques.
• Context is Key: Automated scanners can generate false positives (flagging non-issues) or false negatives (missing actual vulnerabilities). Results always benefit from human review and interpretation, especially by someone with security expertise.
• Complementary, Not a Replacement: These tools should complement, not replace, fundamental security practices. This includes secure coding habits, keeping all software (CMS, plugins, servers) patched and updated, using strong authentication, and, where resources allow, engaging in more thorough security assessments like professional penetration testing.
• Continuous Vigilance: Website security is not a one-time task. Regular scanning is just one part. Continuous monitoring for other issues, such as ensuring your site isn't flagged by Google (which RobotAlp's Safe Browse Monitoring can help with) or experiencing unexpected downtime (covered by our Uptime Monitoring services), is essential for maintaining a robust and trustworthy online presence.

In 2025, website security remains a non-negotiable aspect of any online operation. Fortunately, the availability of powerful free tools means that even those on a tight budget can take significant proactive steps. By leveraging the DAST tools and specialized checkers discussed, you can gain valuable insights into your website's potential vulnerabilities and strengthen its defenses. Remember to combine these tools with sound security practices and a mindset of continuous improvement to build a safer digital experience for your users.