Censys Overview

Censys is a public search engine that enables researchers to quickly ask questions about the hosts and networks that compose the Internet. Details on how Censys is architected and operated are available at About Censys. Instructions on how to use Censys are below.

Censys maintains three datasets through daily ZMap scans of the Internet and by synchronizing with public certificate transparency logs:

You can search for records that meet certain criteria (e.g., IPv4 hosts in Germany manufactured by Siemens, or browser trusted certificates for github.com), generate reports on how websites are configured (e.g., what cipher suites are chosen by popular websites?), and track how networks have patched over time.

We also post all of our raw data, provide programmatic access through a REST API, and publish reports on protocol deployment and the supporting PKI.

Simple Search

If you simply search for a word or phrase, Censys will return any records that contain the phrase. For example, searching for nginx will return any records that contain the word nginx. Searching for 23.0.0.0/8 will return all hosts in that network. Check out some of our example searches.

Advanced Search

Censys data is structured and supports more advanced queries including searching specific fields, specifying ranges of values, and boolean logic. For example, you can search for hosts with the HTTP Server Header "Apache" in Germany by running the query 80.http.get.headers.server: Apache and location.country_code: DE. [more information]