Staff Software Engineer - Site Defense

Reddit's Transport and Site Defense teams build and operate foundational infrastructure behind one of the largest sites in the world. These teams own how requests enter Reddit, how services discover and talk to each other, how traffic moves across clusters and clouds, and how Reddit protects itself from DDoS attacks, scrapers, bots, and other undesired traffic.

We are looking for a Staff Software Engineer to join the Site Defense team within Reddit’s Infrastructure organization. Site Defense is responsible for protecting Reddit at internet scale—serving as the first line of defense against DDoS attacks, automated abuse, large-scale scraping, and other network-level threats. This is a high impact role that sits at the intersection of distributed systems, networking, security, and applied machine learning. You will design and own the critical infrastructure that safeguards Reddit’s data from large scale attacks.

• Design, build, and operate high-scale, low-latency systems that protect Reddit from DDoS attacks, bots, and automated abuse.
• Analyze, develop and evolve ingress-level defenses across CDN, edge, and internal infrastructure layers.
• Build systems to detect, score, and mitigate malicious traffic in real time at per-request and per-user granularity
• Partner closely within Infrastructure and with Security, and internal Safety teams to balance security, performance, and user experience
• Mentor junior engineers in their professional growth.
• Contribute to the team’s ML-at-Ingress initiatives, including experimenting with models for traffic classification, bot detection, and anomaly detection
• Own services end-to-end, including design, implementation, on-call, and operational excellence
• Participate in incident response and post-incident analysis for large-scale network or abuse events

• 7+ years of experience building and operating high throughput and low latency production distributed systems.
• Software development experience in one or more general purpose programming languages; Python, Go, Rust, Java, C++.
• Excellent communication skills to collaborate with a service-oriented team and company.
• Experience with DDoS mitigation, WAFs, bot management, or abuse prevention systems.
• Experience with networking fundamentals (HTTP, TLS, TCP/IP, proxies, CDNs, load balancing).

• Experience with anti-abuse frameworks and bot scores (ReCaptcha, Datadome, Turnstile)
• Experience with browser fingerprinting frameworks (fingerprintJS, ThumbmarkJS)
• Familiarity with ML systems in production, especially real-time inference or feature pipelines.

This job posting may span more than one career level.

In addition to base salary, this job is eligible to receive equity in the form of restricted stock units, and depending on the position offered, it may also be eligible to receive a commission. Additionally, Reddit offers a wide range of benefits to U.S.-based employees, including medical, dental, and vision insurance, 401(k) program with employer match, generous time off for vacation, and parental leave. To learn more, please visit https://www.redditinc.com/careers/.

To provide greater transparency to candidates, we share base salary ranges for all US-based job postings regardless of state. We set standard base pay ranges for all roles based on function, level, and country location, benchmarked against similar stage growth companies. Final offer amounts are determined by multiple factors including, skills, depth of work experience and relevant licenses/credentials, and may vary from the amounts listed below.