Nuclei

Overview

Nuclei is a command-line vulnerability scanner for applications, infrastructure, cloud platforms, and networks. It suits security practitioners and technical teams who want to tailor checks and automate them in development workflows. Its breadth and zero-cost MIT-licensed CLI are strong reasons to consider it; teams seeking a stable, service-oriented scanner should look elsewhere.

Key features

Nuclei’s YAML templates let users run community checks or define their own security tests. The community library has more than 6,500 templates covering real-world vulnerabilities and attack vectors, giving teams a broad starting point without locking them into a fixed scan set. Public templates are reviewed and signed before distribution, and the review process checks for read-only requests and independent validation. Those safeguards help, but they do not eliminate the need to check templates and scope before running scans: some can fuzz or take actions that may cause denial of service. Such templates are tagged and excluded from default scans.

Bulk and parallel scans, multiple target formats, and inclusion and exclusion filters give experienced users control over coverage. Modules span HTTP, DNS, TCP, headless, JavaScript, code, and file checks, while authentication options include HTTP basic authentication and JWT. That range is useful for teams checking different kinds of targets, but the command-line, template-driven approach favors users comfortable choosing and managing checks.

Nuclei can run in CI/CD pipelines, including with GitHub Actions, and export SARIF results to GitHub Code Scanning. That makes it a practical option for automated security testing and regression checks. It can also connect to ProjectDiscovery Cloud Platform to view scans. The project is primarily a standalone CLI tool; the maker warns that running it as a service may pose security risks.

Pricing

The Nuclei CLI costs nothing. The plan is an open-source CLI under the MIT License, with on-premise deployment. Authenticated scans, scheduled scans, compliance reports, and API scanning are included. It is a strong fit for teams able to operate a command-line tool and manage their own scan workflows; there is no paid tier or seat-based limit to weigh against a cheaper plan.

Platforms

Nuclei supports Linux, macOS, and Windows, and can be self-hosted. Installation options include Go, Homebrew, Docker, GitHub, downloadable binaries, and Helm, giving technical teams several ways to fit it into their environments.

Who it's for

ProjectDiscovery identifies security engineers and analysts, red teams, DevOps teams, bug bounty hunters, and penetration testers as Nuclei users. Its customizable checks and CI/CD support particularly suit teams that want repeatable scans and can review templates and scope. It is less suited to users who need a stable long-term release: Nuclei is actively developed, generally releases every two weeks, and has no LTS or stable version, so breaking changes can occur.

Pros and cons

• Pros: A free, MIT-licensed CLI with more than 6,500 community templates offers substantial scope for tailored vulnerability checks.
• Pros: Multiple protocols, authenticated scans, and CI/CD integration support varied targets and automated regression checks.
• Cons: Some templates can cause denial of service, so users need to choose checks and targets carefully despite default exclusions and template review.
• Cons: Active development without an LTS or stable version means breaking changes may disrupt workflows.
• Cons: It is primarily a standalone CLI, and the maker warns against treating it as a service because of security risks.

Alternatives

For another free, open-source scanner, Wapiti supports Linux, macOS, Windows, API, and self-hosted platforms. OWASP ZAP is also free and open source, with support for Linux, macOS, Windows, API, and self-hosted use.

Readers looking for a limited free entry point rather than Nuclei’s open-source CLI can consider Beagle Security, whose free plan includes one lite test per month, monthly surface scan reports, and SSL and domain expiry monitoring. ZeroThreat offers five free scan credits on sign-up, valid for 15 days, then one scan credit per month and one target per account. For a tailored paid solution with pricing based on portfolio, consider Burp Suite DAST.

Qualys External Attack Surface Management offers a 30-day no-cost trial of CSAM with EASM. ImmuniWeb offers a €395 a month subscription for unlimited scans of any builds or versions of the same Android or iOS app. Pentest-Tools.com API Scanner has a NetSec plan from $95 a month with five assets; the price varies by asset count and billing cycle.

Browse Web Application Security Scanners, Network Vulnerability Scanners, and Vulnerability Scanning Software for more options by category.

Verdict

Choose Nuclei if you are a security or DevOps practitioner who wants a free, extensible scanner for customized checks and CI/CD. Its template ecosystem and protocol range are the main draw. Look elsewhere if your workflow depends on a stable release or a service-first deployment, and treat potentially disruptive templates with care.