Software Engineer – Networking

Censys is seeking a software engineer to help build network measurement systems that continually collect data about Internet-connected hosts through Internet-wide scanning, DNS interrogation, and by consuming Certificate Transparency, BGP, and WHOIS data. We perform billions of network handshakes and DNS lookups per hour as well as consume external data feeds to maintain an up-to-date view of all hosts and networks on the Internet.

Your responsibilities will include implementing new network protocols in Go, architecting, building, and deploying new distributed data collection infrastructure, and working with the data engineering team to produce consistent snapshots of Internet composition. For example, you might implement a userland TCP/IP stack in Go to avoid kernel connection overhead, help design a new framework for performing daily DNS lookups for all known domains from distributed vantage points, or implement a high-performance IKE protocol stack in Go to handshake with all listening hosts on the IPv4 space. You will be joining a small, energetic team in Ann Arbor, MI. This position may be remote for a strong candidate.

The types of things you’ll do:

  • Implement high-performance network stacks to scan new protocols, identify vulnerabilities, and label Internet-connected devices 
  • Design and build large-scale network data collection tools in Golang and C 
  • Work with data engineering team to integrate scans into our data pipeline 
  • Analyze network data to uncover scanning problems and better understand Internet behavior

Desired Qualifications

  • Bachelor's degree in Computer Science or related field, or equivalent experience 
  • 3+ years of full-time, industry experience. 
  • Deep understanding of core Internet protocols (e.g., IP, TCP, DNS, BGP) 
  • Experience developing low-level network code (e.g., in C, C++, Rust, Go) 
  • Working knowledge of TLS, X.509, ASN.1 
  • Strong scripting ability in Python/Ruby/BASH

We celebrate diversity and are committed to creating an inclusive environment for all employees. Censys is an equal opportunity employer.

Employment at is based solely on a person's merit and qualifications directly related to professional competence. We do not discriminate based upon race, religion, color, national origin, gender (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, gender expression, age, status as a protected veteran, status as an individual with a disability, any other basis covered by law.

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