Senior Principal Software Engineer
RELX Chatswood, New South Wales, Australia
About the Business
At LexisNexis Risk Solutions Company, we believe in the power of data and advanced analytics for better risk management. With over 40 years of expertise, we are the trusted data analytics provider for organizations seeking actionable insights to manage risks and improve results while upholding the highest standards for security and privacy. Headquartered in metro Atlanta, LexisNexis Risk Solutions serves customers in more than 100 countries and is part of RELX Group plc, a world‑leading provider of information and analytics for professional and business customers across industries. For more information, please visit .
LexisNexis Risk Solutions is an equal‑opportunity employer: qualified applicants are considered for and treated during employment without regard to race, color, creed, religion, sex, national origin, citizenship status, disability status, protected veteran status, age, marital status, sexual orientation, gender identity, genetic information, or any other characteristic protected by law. If a qualified individual with a disability or disabled veteran needs a reasonable accommodation to use or access our online system, that individual should please contact or
About the Team
The LexisNexis Risk Solutions Threat Metrix engineering team is an international team that includes experts in device identification, device intelligence, fraud detection, high performance and low latency real‑time systems, Software as a Service (SaaS) applications, machine learning, and data analytics. We are an Agile engineering team using concepts such as Scrum, Continuous Integration, self‑organizing teams, and Continuous Improvement.
About the Role
Threat Metrix is looking for an experienced developer and systems engineer to work across multiple teams and components. This is not a normal scrum team developer role; this role spans teams and will be required to provide architecture, design, implementation, and review to a broad range of products and technologies across the Threat Metrix platform. There will be research and experimentation around the core principle of improving product efficiency. This is a challenging but fun role.
Threat Metrix platform includes components such as:
* High‑performance C++ servers providing low latency responses to customer queries from around the globe.
* Java applications.
* JavaScript and web technologies applications, iOS and Android mobile apps.
* Web portal architecture.
* Big Data No‑SQL and SQL.
We are looking for an operating system, networks and/or data storage specialist to work with multiple in‑house applications to optimise code, configuration and tuning for our various high performance, low latency software components.
Responsibilities
* Drive production p95/p99 down and throughput up across services and data paths.
* Diagnose hotspots using tcpdump/pcap, kernel metrics and code runtime analysis.
* Tune Linux (RHEL/CentOS/Rocky/Alma) networking: sysctls, queues, IRQ affinity, RPS/RFS, backlog sizing, PMTU/IPv6.
* Read and fix performance issues in C++ (Java is a plus).
* Set client policy guardrails (timeouts/retries/back‑pressure/connection pools) to protect tail latency.
* Lead design and code reviews; write crisp experiment notes; mentor engineers across teams.
Required Technical Skills
* Proven production wins reducing tail latency (p95/p99) on RHEL/CentOS/Rocky/Alma systems.
* Fluency with packet and kernel observation: tcpdump/pcap, ss/netstat, /proc/net/*, sar, perf.
* Concrete Linux networking tuning: SYN/accept backlog, socket buffers, GRO/GSO, PMTU/MSS clamp, IRQ/RPS/RFS/affinity, conn tracking nuances.
* Strong recent hands‑on in C++ (threading/lock contention) and bonus Java (GC ergonomics, thread pools, reactive/async).
Bonus Technical Skills
* NoSQL at scale (Aerospike/Scylla/Cassandra/Redis/Dynamo): data modelling, client policies, compaction/replication trade‑offs.
* TLS termination at scale, proxies/load balancers (Envoy/Nginx/A10), IPv6 edge cases.
* SRE practices: SLIs/SLOs, canaries, chaos, incident reviews.
Requirements
* Excellent written/spoken communication; can align multiple teams with data/presentations.
* Strategic thinking.
* Team player who works effectively with others.
* Detail‑oriented and desire to learn/research/understand.
* Ability to work with geographically dispersed teams in different timezones.
* Ability to accept criticism and provide feedback (e.g. code reviews).
Experience
* 10+ years building high‑performance systems with strong recent hands‑on in C++ (Java a bonus).
* 10+ years OS/kernel/networking configuration & optimisation on Linux in production.
* Code reviews, CI, source control, bug tracking (Atlassian/Jira/Bitbucket or similar).
* Design & architecture for low‑latency, high‑throughput services.
Learn more about the LexisNexis Risk Solutions team and how we work
For additional details, please visit the LexisNexis Risk Solutions careers page.
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