[Hiring] Senior WAF Engineer @Horizon3

Role Description

We're hiring a Senior Web Application Firewall Engineer to be the blue team voice inside the Firewall team. You'll sit between Product and Engineering as the person who defines what "correct" means. When an attack technique is detected, you decide what remediation that claim requires. Your judgment becomes the ground truth.

This is not a coding role and it is not a product management role. Product owns the roadmap, Engineering owns the implementation, and our AI researchers own how the agents reason. You own the domain truth all three depend on, and you make it concrete enough to build and measure against. If you've spent your career being the person in the room who knows how the tools really behave, this is a seat where that knowledge teaches a system instead of firefighting alerts.

Responsibilities

• PRODUCT DIRECTION & REQUIREMENTS
  • Partner with Product to turn WAF effectiveness and tuning ambitions into concrete, buildable requirements.
  • Translate blue team workflows and pain into prioritized product outcomes, and push back when a proposed feature or agent behavior would not hold up in a real SOC.
  • Define acceptance criteria for detection, effectiveness, and tuning features, and validate releases against them before customers see them.
  • Serve as the standing domain reference for Engineering and AI research: available for design reviews, technique questions, and vendor behavior questions.
• FIREWALL & NETWORK POLICY DOMAIN EXPERTISE
  • Own deep, current knowledge of major WAF platforms (i.e. AWS WAF, Cloudflare WAF, F5 Advanced WAF, Imperva, Akamai App & API Protector, FortiWeb, and ModSecurity with OWASP CRS) at the management console, rule/policy configuration, request logging, and API levels.
  • Maintain fluency in how rule evaluation and enforcement work in each product, including rule priority and ordering, managed rule groups, custom rules, rate-based rules, exclusions and exceptions, count/monitor vs. block modes, request body inspection limits, and differences between default and hardened configurations.
  • Define vendor-specific rule semantics so a recommended rule or configuration change has equivalent intent across platforms that model policies differently (e.g., web ACLs and rule groups vs. security policies and signature sets vs. rule chains).
  • Track platform releases, rule and API changes, new managed rule sets, bot and API protection capabilities, and vendor guidance; keep our supported coverage model current as vendors ship.
  • Define what a correct WAF tuning recommendation looks like, e.g. blocking the validated exploit (including realistic encoding and payload variants) while preserving legitimate application traffic, and evaluate remediation output against that standard.
  • Partner with the Attack team so exploit validation, WAF coverage, and remediation guidance stay grounded in current adversary tradecraft and real application behavior.

Qualifications

• 5+ years in application security, security engineering, security operations, incident response, or threat hunting, including 2+ years of hands-on experience administering and tuning WAF platforms in production.
• Hands-on experience administering and tuning WAF platforms in production (i.e. AWS WAF, Cloudflare WAF, F5 Advanced WAF, Imperva, Akamai App & API Protector, FortiWeb, or ModSecurity with OWASP CRS), including custom rules, managed rule groups, rate-based rules, exclusions, and count-to-block rollout.
• Deep understanding of how AppSec and SOC teams use WAF rule outcomes and request logs for triage, containment, and investigation.
• Fluency in false-positive and false-negative tradeoffs, overly permissive rules and exclusions, application-availability risks, and how to assess WAF policy effectiveness and coverage.
• Strong working knowledge of the OWASP Top 10, MITRE ATT&CK (e.g., T1190), and application-control coverage frameworks, with a clear view of where they help and where they can mislead.
• Solid understanding of web attack behavior and how it appears in HTTP requests and WAF telemetry, and how WAF controls can limit exploitation of public-facing applications, injection attacks, credential stuffing and bot abuse, and API abuse.
• Demonstrated experience shaping a product or platform as a domain expert, whether in a security vendor, an internal tooling team, or a detection engineering function.
• Ability to influence without authority. You will not manage the engineers or own the roadmap, and you will still be expected to move both.
• Exceptional technical writing. Most of your leverage here comes from written artifacts — requirements, methodology docs, labeling guides, tuning content.
• Comfort translating between audiences: engineers, AI researchers, product managers, SOC analysts, and executives.
• Enough scripting ability, ideally Python, to query APIs, inspect telemetry, and prototype an analysis.
• Comfort with SQL and with reasoning over large volumes of event and telemetry data.

Benefits

• Inclusive Team: We value diversity and promote an inclusive culture where everyone can thrive.
• Growth Opportunities: Be part of a dynamic and growing team with numerous career development opportunities.
• Innovative Culture: Work in a collaborative environment that encourages creativity and out-of-the-box thinking.
• Remote Work: We are a 100% remote company. Enjoy the flexibility to work in the way that supports you and brings out your best.
• Competitive Compensation: We offer competitive salary, equity and benefits. Our benefits include health, vision & dental insurance for you and your family, a flexible vacation policy, and generous parental leave.