What is Nuclei used for?

Nuclei is a fast vulnerability scanner that uses YAML templates to detect and prioritize exploitable vulnerabilities in applications, infrastructure, cloud platforms, and networks. It is a good fit for identifying vulnerabilities in applications, APIs, networks, DNS, and cloud configurations; bulk scanning of large numbers of assets or websites; and targeted scans for specific vulnerabilities and attack vectors.

Is Nuclei open source?

Yes. Nuclei is open source under the MIT licence. Its source code is on GitHub at projectdiscovery/nuclei and is written mainly in Go.

Yes. Nuclei is open source, so the software itself is free to use. A managed cloud version is also available.

Can I self-host Nuclei?

Yes. Nuclei can be self-hosted on your own server or infrastructure.

What is Nuclei an alternative to?

Nuclei is an open-source alternative to Checkmarx and Qualys. Other open-source alternatives to Checkmarx include DefectDojo, Trivy and Horusec.

Is Nuclei actively maintained?

Yes. The most recent commit to Nuclei was on 13 October 2026, and the latest release is v3.11.1, published on 8 August 2026. The project has 32k stars on GitHub.

Nuclei: open-source alternative to Checkmarx, Qualys

About Nuclei

Nuclei is a vulnerability scanner designed to probe modern applications, infrastructure, cloud platforms, and networks. It uses templates expressed as YAML files to define methods for detecting, ranking, and addressing specific security flaws.

Each template outlines a possible attack route, including vulnerability details, severity, priority rating, and sometimes associated exploits. The tool is suitable for security engineers, developers, organizations, bug bounty hunters, and penetration testers.

Key features

Extensive template library with community-powered templates for various vulnerabilities and attack vectors
Versatile target specification: URLs, IP ranges, ASN range, and file input
Bulk scanning of multiple targets at once
Flexible customization of scanning templates

Good fit for

Identifying vulnerabilities in applications, APIs, networks, DNS, and cloud configurations
Bulk scanning of large numbers of assets or websites
Targeted scans for specific vulnerabilities and attack vectors

Built with: Go tools
Tags: vulnerability-scanner; yaml; security; templates; open-source

Nuclei: questions and answers

What is Nuclei used for?: Nuclei is a fast vulnerability scanner that uses YAML templates to detect and prioritize exploitable vulnerabilities in applications, infrastructure, cloud platforms, and networks. It is a good fit for identifying vulnerabilities in applications, APIs, networks, DNS, and cloud configurations; bulk scanning of large numbers of assets or websites; and targeted scans for specific vulnerabilities and attack vectors.
Is Nuclei open source?: Yes. Nuclei is open source under the MIT licence. Its source code is on GitHub at projectdiscovery/nuclei and is written mainly in Go.
Is Nuclei free?: Yes. Nuclei is open source, so the software itself is free to use. A managed cloud version is also available.
Can I self-host Nuclei?: Yes. Nuclei can be self-hosted on your own server or infrastructure.
What is Nuclei an alternative to?: Nuclei is an open-source alternative to Checkmarx and Qualys. Other open-source alternatives to Checkmarx include DefectDojo, Trivy and Horusec.
Is Nuclei actively maintained?: Yes. The most recent commit to Nuclei was on 13 October 2026, and the latest release is v3.11.1, published on 8 August 2026. The project has 32k stars on GitHub.