Nuclei

Overview

Nuclei is a template-driven vulnerability scanner operated primarily from the command line. It suits security practitioners and technical teams who want to tailor checks across applications, infrastructure, cloud platforms, and networks. Its strongest case is flexible, free scanning that can join development workflows; teams needing a stable, service-oriented product should look elsewhere.

Key features

Users can run community YAML templates or write checks of their own. The library exceeds 6,500 templates for real-world vulnerabilities and attack vectors, and public templates are reviewed, signed, checked for read-only requests, and independently validated before merge. That process is a meaningful safeguard, but not a substitute for controlling scan scope: some templates can fuzz or take actions that risk denial of service. Those templates are tagged and excluded from default scans.

Bulk and parallel scans, support for multiple target formats, and inclusion and exclusion filters give security teams practical control over coverage. Modules include HTTP, DNS, TCP, headless, JavaScript, code, and file checks; authentication options include HTTP basic authentication and JWT. This range makes Nuclei useful beyond conventional web checks, though selecting suitable templates and targets requires technical judgment.

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

Installation options include Go, Homebrew, Docker, GitHub, downloadable binaries, and Helm. ProjectDiscovery actively maintains Nuclei and generally releases every two weeks, but there is no LTS or stable version; breaking changes can arrive during active development. Users should be prepared to follow releases and adjust workflows. Support is available through ProjectDiscovery Discord or GitHub.

Pricing

Nuclei CLI costs nothing. The plan is open-source and MIT licensed, with on-premise deployment; it is primarily intended as a standalone tool. For security engineers, red teams, DevOps teams, bug bounty hunters, and penetration testers who can operate a CLI, that removes a purchase barrier while retaining room to customize checks. There is no paid tier described for this plan, so teams wanting a stable service-oriented deployment should weigh the operational and security cautions rather than assume the free CLI is a managed service.

The plan supports authenticated scans, scheduled scans, compliance reports, and API scanning. Nuclei’s free price is especially attractive for teams able to integrate and maintain it themselves; the trade-off is active development and the care required around potentially disruptive templates.

Platforms

Nuclei runs on Linux, macOS, and Windows, and supports self-hosted use. Installation choices span Go, Homebrew, Docker, GitHub, binaries, and Helm. This gives technical teams flexibility in how they install it, while its command-line focus is less suited to organizations seeking a conventional hosted scanning service.

Who it's for

Nuclei is aimed at security engineers and analysts, red teams, DevOps teams, bug bounty hunters, and penetration testers. It fits teams that need customizable checks, broad protocol coverage, or repeatable scans in CI/CD. It is a weaker fit for users who want a stable release track or plan to run the scanner as a service.

Pros and cons

Broad, customizable coverage: More than 6,500 community templates, custom checks, and multiple protocol modules support varied targets.

Useful workflow integration: GitHub Actions and SARIF export to GitHub Code Scanning let teams put scans into existing CI/CD processes.

No license cost: The free, MIT-licensed CLI can be deployed on-premise and used for authenticated, scheduled, compliance, and API scans.

Scan impact needs attention: Some templates can cause denial of service, so teams should review scope and template choice despite tagging and default exclusions.

Changing interfaces: No stable or LTS version and possible breaking changes make maintenance a continuing responsibility.

Not designed as a service: Nuclei is primarily a standalone CLI, and service deployment carries a stated security risk.

Alternatives

For a different open-source web scanner, Wapiti is also free and supports Linux, macOS, Windows, API, and self-hosted use; its GNU GPL version 2 license differs from Nuclei’s MIT license.

Beagle Security is worth considering for web and API scanning if a freemium option with a free plan, trial, one lite test per month, monthly surface scan reports, and SSL and domain-expiry monitoring fits better. Its Essential plan costs $99 a month, billed annually at $1188.

Qualys External Attack Surface Management may suit readers seeking its freemium offering; it has no free plan, but offers a 30-day no-cost CSAM with EASM trial. Pentest-Tools.com API Scanner is another freemium option, with a NetSec plan from $95 a month with five assets; price varies by asset count and billing cycle.

ZeroThreat offers a free plan with five scan credits on sign-up valid for 15 days, then one scan credit per month and one target per account. Detectify Surface Monitoring has a free Starter plan at free with up to five users and one team, while Surface Monitoring costs extra per domain; its Standard plan is €2,500 a year.

Readers comparing other tools can browse Web Application Security Scanners, Network Vulnerability Scanners, or Vulnerability Scanning Software. Burp Suite DAST and Rapid7 Surface Command are alternatives with custom pricing.

Verdict

Choose Nuclei if you are a security or DevOps practitioner who wants a free, customizable scanner that can cover varied targets and run in CI/CD. Its template breadth and automation are compelling, but the need to manage disruptive checks and breaking changes is real. Look elsewhere if you need a stable release track or a scanner designed to operate as a service.