Member of Technical Staff (Software Engineer, Fraud Prevention) at Perplexity (London, United Kingdom)
Perplexity· London, United Kingdom·
Role details
Perplexity at a glance
AI-powered answer engine that returns real-time, cited answers, now expanding into an agentic browser and on-device agents.
Perplexity runs an AI answer engine that searches the live web and returns direct, cited answers instead of a page of links. It has extended that core into an AI browser (Comet), an on-device agent (Computer), a developer API, and vertical tools like patent search.
$1.7B raised · latest: Series E extension · $200M · 2025 (reported $20B valuation) · backed by Accel, IVP, NEA, SoftBank Vision Fund 2
Job description
About the role
Perplexity's fraud prevention team protects our products, users, and infrastructure from fraud and abuse across the whole lifecycle: sign-up, authentication, payments, API usage, and product features. We build and operate a real-time decisioning platform together with the surrounding systems: data pipelines for detection and model training, integrations with product and payment systems, and internal tooling for investigation and response. As a software engineer on the team, you will own services end to end, from design to production operations, and work closely with fraud analysts, ML engineers, and product teams to make abuse expensive and legitimate usage frictionless.
Responsibilities
- Design, build, and operate high-throughput, low-latency backend services for fraud detection and prevention
- Build data pipelines and real-time feature computation that power detections and ML models
- Collect and process trust signals
- Integrate fraud decisions into product, auth, and payment flows across Perplexity
- Own reliability of production services: observability, alerting, safe rollouts, incident response
- Build internal tooling for investigation, enforcement, and auditability
- Partner with fraud analysts to turn new abuse patterns into production detections quickly
Qualifications
- 5+ years building and operating high-throughput, latency-sensitive backend systems in production
- Strong systems programming skills; Rust, Go, or C++ experience preferred (we write Rust)
- Hands-on experience with Kubernetes, Terraform and cloud infrastructure
- Solid data fundamentals: stream/batch computations, caching and storage trade-offs
- Pragmatic, ownership-driven approach: ship incrementally, measure, and make failures degrade safely
Nice to have
- Fraud prevention, anti-abuse, or payments-risk domain experience
- Experience serving ML models in production
- Client-side experience (web or mobile) for signal collection
Why work at Perplexity
- Culture & Environment: “Thoughtful support” culture with emphasis on craftsmanship, ownership, entrepreneurship, scholarship, and partnership. Hybrid schedule (4 days in-office) based on location.
- Perks: Daily catered meals (breakfast, lunch, dinner in office), office snacks, ride home program, commuter benefits, home office reimbursement, fitness classes, gym memberships.
- Compensation & Benefits: Competitive salary and equity packages; retirement plans with company match; flexible PTO; holiday shutdown between Christmas and New Year; 12 weeks paid bonding leave; comprehensive health, dental, and vision insurance.
- Relocation & Visa Support: Relocation assistance and visa/green card sponsorship for eligible roles. Partners with immigration firm to support the process.
- Engineering Excellence: “Technical assessment for relevant roles”; values hands-on contribution, broad skill sets, and merit-based evaluation. Frequent Tech Talks and exposure to greenfield AI research problems.