December 15, 2020

1437 words 7 mins read



Nuclei is a fast tool for configurable targeted scanning based on templates offering massive extensibility and ease of use.

repo name projectdiscovery/nuclei
repo link
language Go
size (curr.) 7917 kB
stars (curr.) 2287
created 2020-04-03
license MIT License

License Go Report Card contributions welcome GitHub Release Follow on Twitter Docker Images Chat on Discord

Nuclei is a fast tool for configurable targeted scanning based on templates offering massive extensibility and ease of use.

Nuclei is used to send requests across targets based on a template leading to zero false positives and providing effective scanning for known paths. Main use cases for nuclei are during initial reconnaissance phase to quickly check for low hanging fruits or CVEs across targets that are known and easily detectable. It uses retryablehttp-go library designed to handle various errors and retries in case of blocking by WAFs, this is also one of our core modules from custom-queries.

We have also open-sourced a template repository to maintain various type of templates, we hope that you will contribute there too. Templates are provided in hopes that these will be useful and will allow everyone to build their own templates for the scanner. Checkout the templating guide at for a primer on nuclei templates.



  • Simple and modular code base making it easy to contribute.
  • Fast And fully configurable using a template based engine.
  • Handles edge cases doing retries, backoffs etc for handling WAFs.
  • Smart matching functionality for zero false positive scanning.

Installation Instructions

From Binary

The installation is easy. You can download the pre-built binaries for your platform from the Releases page. Extract them using tar, move it to your $PATHand you’re ready to go.

Download latest binary from

▶ tar -xzvf nuclei-linux-amd64.tar.gz
▶ mv nuclei /usr/local/bin/
▶ nuclei -version

From Source

nuclei requires go1.14+ to install successfully. Run the following command to get the repo -

▶ GO111MODULE=on go get -v

From Github

▶ git clone; cd nuclei/v2/cmd/nuclei/; go build; mv nuclei /usr/local/bin/; nuclei -version

Nuclei templates

You can download or update the nuclei templates using update-templates flag.

▶ nuclei -update-templates

or download it from nuclei templates Github project.

▶ git clone

Please refer to nuclei templating guide to writing your own custom templates.


nuclei -h

This will display help for the tool. Here are all the switches it supports.

Flag Description Example
bulk-size Max hosts analyzed in parallel per template ( default 25) nuclei -bulk-size 25
burp-collaborator-biid Burp Collaborator BIID nuclei -burp-collaborator-biid XXXX
c Max templates processed in parallel (default 10) nuclei -c 10
l List of urls to run templates nuclei -l urls.txt
target Target to scan using Templates nuclei -target hxxps://
t Templates input file/files to check across hosts nuclei -t git-core.yaml -t cves/
no-color Don’t Use colors in output nuclei -no-color
no-meta Don’t display metadata for the matches nuclei -no-meta
json Prints and write output in json format nuclei -json
include-rr Inlcude req/resp of matched output in JSON output nuclei -json -include-rr
o File to save output result (optional) nuclei -o output.txt
project Project flag to avoid sending same requests nuclei -project
project-path Use a user defined project folder nuclei -project -project-path test
stats Enable the progress bar (optional) nuclei -stats
silent Show only found results in output nuclei -silent
retries Number of times to retry a failed request nuclei -retries 1
timeout Seconds to wait before timeout (default 5) nuclei -timeout 5
trace-log File to write sent requests trace log nuclei -trace-log logs
rate-limit Maximum requests/second (default 150) nuclei -rate-limit 150
severity Run templates based on severity nuclei -severity critical,high
stop-at-first-match Stop processing http requests at first match nuclei -stop-at-first-match
exclude Template input dir/file/files to exclude nuclei -exclude panels -exclude tokens
debug Allow debugging of request/responses. nuclei -debug
update-templates Download and updates nuclei templates nuclei -update-templates
update-directory Directory for storing nuclei-templates(optional) nuclei -update-directory templates
tl List available templates nuclei -tl
templates-version Shows the installed nuclei-templates version nuclei -templates-version
v Shows verbose output of all sent requests nuclei -v
version Show version of nuclei nuclei -version
proxy-url Proxy URL nuclei -proxy-url hxxp://
proxy-socks-url Socks proxyURL nuclei -proxy-socks-url socks5://
random-agent Use random User-Agents nuclei -random-agent
H Custom Header nuclei -H “x-bug-bounty: hacker”

Running Nuclei

Running with single template.

This will run git-core.yaml template against all the hosts in urls.txt and returns the matched results.

▶ nuclei -l urls.txt -t files/git-core.yaml -o results.txt

You can also pass the list of urls at standard input (STDIN). This allows for easy integration in automation pipelines.

▶ cat urls.txt | nuclei -t files/git-core.yaml -o results.txt

💡 Nuclei accepts list of URLs as input, for example here is how urls.txt looks like:-

Running with multiple templates.

This will run the tool against all the urls in urls.txt with all the templates in the cves and files directory and returns the matched results.

▶ nuclei -l urls.txt -t cves/ -t files/ -o results.txt

Running with subfinder.

▶ subfinder -d -silent | httpx -silent | nuclei -t cves/ -o results.txt

Running in Docker container

You can use the nuclei dockerhub image. Simply run -

▶ docker pull projectdiscovery/nuclei

After downloading or building the container, run the following:

▶ docker run -it projectdiscovery/nuclei

For example, this will run the tool against all the hosts in urls.txt and output the results to your host file system:

▶ cat urls.txt | docker run -v /path/to/nuclei-templates:/app/nuclei-templates -v /path/to/nuclei/config:/app/.nuclei-config.json -i projectdiscovery/nuclei -t /app/nuclei-templates/files/git-config.yaml > results.txt

Remember to change /path-to-nuclei-templates to the real path on your host file system.

Rate Limits

Nuclei have multiple rate limit controls for multiple factors including a number of templates to execute in parallel, a number of hosts to be scanned in parallel for each template, and the global number of request / per second you wanted to make/limit using nuclei, as an example here is how all this can be controlled using flags.

  • -c flag => Limits the number of templates processed in parallel.
  • -bulk-size flag => Limits the number of hosts processed in parallel for each template.
  • -rate-limit flag => Global rate limiter that ensures defined number of requests/second across all templates.

If you wanted go fast or control the scans, feel free to play with these flags and numbers, rate-limit always ensure to control the outgoing requests regardless the other flag you are using.

Template Exclusion

Nuclei-templates includes multiple checks including many that are useful for attack surface mapping and not necessarily a security issue, in cases where you only looking to scan few specific templates or directory, here are few options / flags to filter or exclude them from running.

Running templates with exclusion

We do not suggest running all the nuclei-templates directory at once, in case of doing so, one can make use of exclude flag to exclude specific directory or templates to ignore from scanning.

nuclei -l urls.txt -t nuclei-templates -exclude panels/ -exclude technologies -exclude files/wp-xmlrpc.yaml

Note:- both directory and specific templates case be excluded from scan as shared in the above example.

Running templates based on severity

You can run the templates based on the specific severity of the template, single and multiple severity can be used for scan.

nuclei -l urls.txt -t cves/ -severity critical,medium

The above example will run all the templates under cves directory with critical and medium severity.

nuclei -l urls.txt -t panels/ -t technologies -severity info

The above example will run all the templates under panels and technologies directory with severity marked as info

Using .nuclei-ignore file for template exclusion

Since release of nuclei v2.1.1, we have added support of .nuclei-ignore file that works along with update-templates flag of nuclei, in .nuclei-ignore file, you can define all the template directory or template path that you wanted to exclude from all the nuclei scans, to start using this feature, make sure you installed nuclei templates using nuclei -update-templates flag, now you can add/update/remove templates in the file that you wanted to exclude from running.

nano ~/nuclei-templates/.nuclei-ignore

Default nuclei-ignore list can be accessed from here, in case you don’t want to exclude anything, simply remove the .nuclei-ignore file.

📋 Notes

  • Progress bar is experimental feature, might not work in few cases.
  • Progress bar doesn’t work with workflows, numbers are not accurate due to conditional execution.


nuclei is made with 🖤 by the projectdiscovery team. Community contributions have made the project what it is. See the file for more details.

Do also check out these similar awesome projects that may fit in your workflow:

Burp Suite, FFuF, Jaeles, Qsfuzz, Inception, Snallygaster, Gofingerprint, Sn1per, Google tsunami, ChopChop

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