Staff Networking Systems Engineer- Internet Map

Censys is building the most credible, robust map of the Internet through IP scanning, DNS lookups, web crawling, and the ingestion of millions of certificates. Censys was founded by security researchers who are passionate about developing technology that provides anyone the power to fully understand their digital risk and exposure. Individuals and enterprises–and anyone in between–can harness this power to discover new information and insight as the Internet, IoT and Cloud evolve.  We are a true security startup with midwestern roots and we believe that a map of the Internet, or a map of your organization’s assets can quickly help guide organizations to the answers they need to protect themselves from vulnerability and risk.

Location: This position is remote within the United States or Canada

Role Summary: 

We are looking for a Staff Networking Systems Engineer to help design, build, and operate the systems that continuously scan the Internet through IP scanning, DNS resolution, and web crawling.

This role sits at the intersection of network protocol engineering, systems programming, distributed systems, and applied Internet research. You will work on production systems that discover and collect Internet-scale data across IPs, domains, certificates, web services, and cloud infrastructure. You will help improve the accuracy, coverage, freshness, and reliability of the Internet Map that powers Censys’ products and research.

At Censys, we work iteratively, but we are always thinking about the big picture. We’re expanding our scanning capabilities to discover more of the Internet and keep our map current. We are looking for someone with deep knowledge of networking protocols and hands-on systems programming experience, who understands how network software interacts with the operating system and hardware. You will bring strong technical ownership and production engineering judgment, and mentor others while building reliable systems.

What You’ll Do:

• Design, build, and operate Internet-scale scanning, DNS, web crawling, and data collection systems.
• Own production scanning services and collection pipelines, from packet capture and connection handling through reliable delivery of collected data.
• Improve the quality, freshness, reliability, and coverage of Censys’ Internet Map.
• Implement and extend protocol handshakes, parsers, and probes to discover services and collect accurate data.
• Lead technical design for scanning engines, scheduling systems, and distributed scan orchestration, balancing coverage and freshness with throughput, resource efficiency, and responsible scan rates.
• Partner with Research, Product, Security, and Engineering teams to turn research ideas into safe, scalable, production-ready systems.
• Make thoughtful architectural tradeoffs around reliability, cost, scale, latency, data quality, and operational complexity.
• Participate in operational ownership of the systems you build, including observability, incident response, and on-call rotation.
• Provide scross-team technical leadership, mentor engineers, review designs, and help raise the technical bar for networking, systems programming, and scanning infrastructure.

Skills You Have:

• 10+ years of software engineering experience building production systems.
• Deep systems programming experience and strong understanding of Linux networking internals and how user-space code interacts with the kernel and network interfaces, including sockets, buffers, system calls, and I/O scheduling.
• Deep knowledge of networking across the stack, from Ethernet and ARP through IPv4/IPv6, ICMP, TCP/UDP, TLS, DNS, and HTTP. Ability to reason about packet flow, routing, connection state, retransmissions, and protocol behavior on real networks.
• Experience designing and operating systems that handle large-scale data, high request volume, or Internet-scale workloads, with a track record of diagnosing performance and reliability issues across application code, the operating system, and the network.
• Strong programming experience in Go, C, C++, or Rust, with the ability to work close to operating system and networking interfaces; we primarily use Go.
• Experience with cloud infrastructure such as AWS, GCP, or Azure.
• Strong understanding of reliability, observability, testing, deployment, and operational ownership.
• Ability to write understandable, testable, maintainable code.
• Strong technical communication skills, with the ability to explain complex systems to engineers, product managers, researchers, and leadership.
• Good judgment around when and how to use AI-assisted development tools.

Things that make you stand out:

• Experience building or operating scanners, crawlers, DNS infrastructure, passive/active measurement systems, or Internet data collection platforms.
• Deep understanding of DNS and how it is used in practice, including resolution, delegation, record types, nameservers, and operational edge cases.
• Experience developing kernel networking code, network drivers, user-space network stacks, or packet processing systems using technologies such as eBPF/XDP.
• Experience implementing or extending protocol stacks, network measurement tools, or service discovery and protocol fingerprinting capabilities.
• Experience turning research prototypes into reliable, maintainable production systems.
• Familiarity with gRPC, REST, Protobuf, MessagePack, or other API and serialization technologies.
• Experience building, deploying, and maintaining containerized services in Kubernetes.
• Experience with scan orchestration, scheduling, rate limiting, backpressure, retries, deduplication, or distributed task execution.
• Experience working across the boundary of research and engineering, especially in security, infrastructure, networking, or Internet measurement.
• Curiosity about how the Internet works and a desire to build systems that make it more understandable.

For high cost of living areas (San Francisco Bay, New York City, and Seattle), the expected salary range for this position is $198,000 USD – $233,000 USD, plus bonus eligibility and equity.

For all other US locations, the expected salary range for this position is $172,000 USD – $216,000 USD, plus bonus eligibility and equity.

Censys offers a competitive benefits package to employees, including equity, health, dental & vision coverage, retirement with company contribution, parental leave, mental health & wellness benefits, flexible PTO, and a professional development stipend. 

We will work to ensure individuals with disabilities are provided reasonable accommodation to apply for a role, participate in the interview process, perform essential job functions, and receive other benefits and privileges of employment. If you require accommodation, please reach out to your recruiter. These modifications enable an individual with a disability to have an equal opportunity not only to get a job, but successfully perform their job tasks to the same extent as people without disabilities.

By applying for this job, the candidate acknowledges and agrees that any personal data contained in their application or supporting materials will be processed in accordance with our Censys Privacy Policy.

Our roots are in Ann Arbor, Michigan and our innovation is fueled by the team’s global perspectives. For this role, we are open to remote employees across the continental US. We value diversity and are committed to creating an inclusive environment for all employees. Censys is an equal opportunity employer.