Data Scientist/Engineer – Online Metrics at Perplexity | London

At Perplexity, we empower millions of users every day with accurate, high-quality answers through our innovative LLM-first search engine and specialized data sources. Join our Answer Quality team, where we focus on enhancing user experience by ensuring our prompts, tools, search capabilities, and specialized datasets, combined with both cutting-edge and in-house models, provide the best results. As a Data Scientist/Engineer, you will analyze online signals derived from user interactions to connect shifts in answer quality with actual user behavior.Key ResponsibilitiesIdentify and validate online signals from user interactions that act as dependable indicators of true answer quality.Develop and implement innovative online metrics for tracking in A/B testing and product health dashboards, ensuring alignment with ground-truth evaluations.Evaluate experimental results to validate these metrics, ensuring they accurately reflect user satisfaction and guide product decisions.Construct and sustain data pipelines that compute these metrics at scale, providing actionable quality signals to Search, Product, and model training teams.Share insights and foster collaboration with Product and Search teams to enhance clarity and understanding.Contribute to a small, high-impact team where your work is instrumental in shaping how Perplexity measures and enhances Answer Quality.QualificationsMaster's degree in a technical field or equivalent professional experience.4+ years of experience in roles such as Data Scientist, Analytics Engineer, or similar positions.Proven experience with search, recommendation, or LLM-based products, particularly in designing online metrics and analyzing A/B tests.Strong coding skills in Python and SQL, with the ability to produce production-grade code.In-depth knowledge of statistical analysis methodologies.Experience using Business Intelligence (BI) tools for data visualization and reporting.Comfortable with coding workflows and using AI-assisted development tools for rapid iteration.Preferred QualificationsFamiliarity with Apache Spark and Databricks.Experience in developing or validating LLM-as-a-judge systems.Previous experience supporting large-scale customer-facing products.

Join Perplexity, a pioneering firm serving millions of users daily by providing reliable and high-quality answers through an innovative LLM-first search engine combined with specialized data sources. Our Answer Quality team plays a crucial role in refining prompts, tools, searches, and specialized datasets, ensuring that our evaluations are fast, accurate, and actionable. In this exciting role, you will be instrumental in building the data flywheel that supports various teams across Perplexity.ResponsibilitiesDevelop and maintain systems and pipelines that empower Search, Product, and other teams to independently access reliable evaluation verdicts without delays.Take charge of the "evals-to-product" loop, autonomously transforming raw signals into robust datasets that drive decision-making throughout the organization.Construct a sophisticated simulator pipeline capable of replaying user interactions with the product in formats comprehensible to LLMs and VLMs, reflecting real-time product updates.Ensure data integrity by implementing monitoring, lineage tracking, and quality checks, providing downstream consumers with reliable results.Collaborate within a small, impactful team where your contributions will directly influence how Perplexity measures and enhances Answer Quality.

Join our innovative team at Perplexity as an AI Inference Engineer, where you'll be at the forefront of deploying machine learning models for real-time inference. Our technology stack includes Python, Rust, C++, PyTorch, Triton, CUDA, and Kubernetes. This is a fantastic opportunity to contribute to large-scale ML applications.Key ResponsibilitiesDevelop robust APIs for AI inference catering to both internal and external clients.Conduct benchmarking and resolve performance bottlenecks in our inference stack.Enhance system reliability and observability, responding effectively to outages.Investigate cutting-edge research and implement optimizations for LLM inference.

Join Perplexity, a pioneering company based in London, as we transform the way users search and engage with the internet. We are seeking seasoned Infrastructure Engineers to become integral members of our dynamic team. In this role, you will lead the design, implementation, and scaling of innovative tools, systems, and platforms that empower web, mobile, and browser engineers to develop cutting-edge products. Your contributions will be vital in enabling our product, AI, and development teams to innovate swiftly while ensuring utmost reliability, security, and performance at scale.Our Tech StackPython | Go | TypeScript | PostgreSQL | DynamoDB | Redis | FastAPI | React | Bazel | GitHub | AWSTeams HiringSenior/Staff PlatformThe Platform team is fundamental to ensuring product reliability, scalability, and performance at Perplexity. This elite team is responsible for developing and maintaining the critical infrastructure—from backend systems such as authentication, real-time data flows, and service orchestration to frontend frameworks that guarantee fast, reliable, and secure user experiences. By upholding stringent standards for code quality, uptime, and developer productivity, the Platform team enables all of Perplexity to innovate rapidly on a solid, well-designed foundation.Senior/Staff DevXThe Developer Experience (DevX) team is dedicated to empowering engineers at Perplexity to build, ship, and iterate faster than ever before. They manage internal platforms for source control, build, test, and deployment, effectively removing bottlenecks from each phase of product development. This team designs seamless onboarding, ultra-fast CI/CD pipelines, and developer tools that enhance creativity and safety at scale. Through collaborative efforts and significant autonomy, the DevX team amplifies the contributions of every engineer, facilitating rapid, dependable innovation across the organization.Senior/Staff Cloud InfraThe Cloud Infrastructure team architects and manages the essential cloud infrastructure that powers Perplexity’s global platform. This team designs and scales computing, storage, and networking systems to support high-throughput, low-latency workloads, balancing proactive project initiatives with operational support. Collaboration with product, AI research, security, and other teams ensures that our services remain consistently available, reliable, and responsive to user demands.

Join Perplexity, a cutting-edge company serving millions of users each day with high-quality answers powered by an LLM-first search engine and specialized data sources. We strive to leverage the latest models as they become available, navigating the complexities of the intelligence frontier where traditional benchmarks may fall short. In this pivotal role, you will be responsible for creating specialized evaluations aimed at enhancing answer quality across Perplexity, specifically focusing on search-based LLM responses and other user-favored scenarios.ResponsibilitiesDesign and manage automated evaluation pipelines that measure answer quality across Perplexity's products, ensuring adherence to high standards of accuracy and usefulness.Create tailored evaluation datasets and methodologies to assess the influence of tool calls, particularly in web search retrieval, on the quality of final answers.Develop VLM-based solutions to programmatically analyze the visual rendering of final answers across various platforms and devices.Consistently evaluate public benchmarks and academic assessments for their relevance to Perplexity's offerings, adapting and integrating them into our ongoing performance evaluations.Collaborate within a small, high-impact team where your evaluation metrics will directly influence product enhancements, working closely with technical leadership to measure and elevate Answer Quality.QualificationsPhD or MS in a technical discipline or equivalent practical experience.A minimum of 4 years of experience in data science or machine learning.Proficient in Python and SQL, with the ability to write production-quality code.Experience with modern cloud data stacks, particularly AWS and Databricks.Familiarity with agentic coding workflows and utilizing AI-assisted development tools for efficient iteration.Preferred QualificationsAt least 1 year of experience working with LLMs at scale, especially in LLM-as-a-judge configurations.Experience developing customer-facing web products or consumer applications with significant user traffic.A robust research background, demonstrating the application of research methodologies to real-world machine learning challenges.Experience in defining evaluation metrics, such as factual consistency, hallucination rate, and retrieval precision, along with creating ground truth datasets.

Perplexity is thrilled to introduce our Internship Program, designed for outstanding Master’s or PhD students specializing in Computer Science or Engineering in the UK for the 2025-2026 academic year. This immersive program offers a direct collaboration with our AI Inference team, providing a distinctive opportunity to acquire invaluable experience within a rapidly expanding AI startup. Exceptional interns may receive an offer for a full-time position upon completion of the program.Our AI Inference team is integral to the performance of Perplexity's products, overseeing the inference engine and deployments for models ranging from single-node embeddings to advanced distributed sparse Mixture-of-Experts models, all while managing extensive GPU clusters. With a focus on optimizing latency and throughput, the Inference team encompasses the entire serving stack, from GPU kernels to networking and monitoring infrastructure.

Join our dynamic team at Trainline as a Data Scientist, where you will leverage data to drive insights and influence strategic decisions. You will work with cross-functional teams to develop models that enhance our customer experience and optimize our operations. If you have a passion for data and want to make a real impact in the travel industry, this is the opportunity for you!

Join our dynamic team at Faculty as a Data Scientist, where your analytical prowess will help drive impactful decisions across various sectors. In this role, you'll leverage advanced statistical techniques and machine learning algorithms to extract insights from complex datasets, delivering actionable recommendations to stakeholders. Collaborate with cross-functional teams to innovate and optimize data-driven solutions that enhance our clients' operational efficiency.

Join Abound, a forward-thinking company dedicated to leveraging data to drive innovative solutions. As a Data Scientist, you will play a crucial role in analyzing complex datasets, developing predictive models, and transforming data into actionable insights. Collaborate with cross-functional teams to enhance our products and services, ensuring that data-driven decisions are at the forefront of our strategy.

Join our dynamic team at Intercom as a Senior Data Scientist, where you will leverage your analytical expertise to drive data-driven decisions and contribute to our innovative product development. In this role, you will collaborate with cross-functional teams to build models that enhance user experiences and optimize our services.

At Perplexity, we are transforming the way individuals discover and engage with information through cutting-edge AI-powered search and knowledge tools. As we broaden our global reach, we are excited to establish a significant presence in London, a key hub for innovation and growth across Europe.The Role:We are in search of an outstanding Site Lead to launch and expand our London office. This is a remarkable opportunity to define Perplexity's footprint in one of the world's foremost technology centers, where you will cultivate teams and a vibrant culture from the ground up, all while propelling technical brilliance in infrastructure and AI systems.As the Site Lead, you will be the representative of Perplexity in London, tasked with constructing our technical organization, nurturing a premier engineering culture, and directly overseeing one or more infrastructure teams. Your role will involve reporting to senior leadership and collaborating across various teams within our global network.

Join ravio as a Senior Data Scientist and lead innovative projects to harness the potential of big data. You will work closely with cross-functional teams to extract valuable insights, develop predictive models, and enhance data-driven decision-making processes. This role offers an exciting opportunity to impact our data strategy and drive meaningful change.

Join Entain, a global leader in sports betting and gaming entertainment, as a Senior Data Scientist. In this pivotal role, you will leverage cutting-edge analytics and machine learning techniques to drive data-driven decisions that enhance our customer experience and optimize business operations.Your expertise will be critical in developing predictive models, conducting complex data analyses, and collaborating with cross-functional teams to implement data strategies that support our ambitious growth objectives.

Why Join Faculty?Founded in 2014, Faculty is at the forefront of artificial intelligence, believing it to be the defining technology of our era. With a proven track record, we have partnered with over 350 global clients to enhance their performance through human-centric AI solutions. Discover our impact here.We prioritize genuine innovation over fleeting trends. Our commitment to responsible AI enables us to deliver solutions that drive significant results. Our extensive expertise spans across various sectors, including government, finance, retail, energy, life sciences, and defense.As our business continues to expand rapidly, we seek individuals who possess intellectual curiosity and a passion for leveraging technology to create a lasting positive impact.Join us in harnessing the power of AI to redefine its applications and make a tangible difference.About Our TeamThe Frontier TM product represents our bold ambition to create an enterprise-grade platform that integrates decision intelligence and AI Agents, optimizing critical processes in large organizations. You will tackle complex challenges within the real economy, focusing especially on healthcare and life sciences.Your RoleAs a Senior Data Scientist on the Frontier team, you will shape the future of our Decision Intelligence Platform by developing AI-powered digital twins that enhance organizational decision-making. This entrepreneurial role involves solving intricate problems while enabling enterprise users to leverage state-of-the-art AI technologies. You will combine scientific rigor with a business-oriented mindset to advance our AI Agent and Decision Hub capabilities.Key Responsibilities:Designing and Building: Create agents for high-stakes environments, ensuring that outputs meet rigorous validation standards.Data Analysis: Conduct exploratory data analysis, model development, validation, and performance monitoring.Leadership: Guide data science initiatives within cross-functional delivery teams, collaborating with engineers, designers, and business stakeholders.

Why Join Faculty?Founded in 2014, Faculty believes that AI is the defining technology of our era. We have successfully partnered with over 350 global clients to enhance performance through human-centric AI solutions. Discover our real-world impact here.We prioritize innovation over hype, focusing on creating and implementing responsible AI that truly makes a difference. Our extensive expertise spans various sectors, including government, finance, retail, energy, life sciences, and defense.As our business and reputation continue to expand rapidly, we are eager to recruit individuals who are intellectually curious and passionate about building a positive legacy through technology.Join us in leveraging AI’s transformative power to revolutionize decision-making processes in critical fields.About the TeamThe Faculty Frontier™ product represents our ambitious goal of developing the first enterprise-grade platform that integrates decision intelligence with AI agents to optimize key processes in large organizations. You will tackle complex challenges with a focus on healthcare and life sciences.Role OverviewAs a Senior Data Scientist, you will play a pivotal role in shaping our Frontier Decision Intelligence Platform. You will lead the design and implementation of AI-powered digital twins that redefine organizational decision-making. Working within cross-functional teams, you will blend technical prowess with commercial insight to address intricate customer challenges. This is also an opportunity to mentor emerging talent while delivering impactful, production-grade AI solutions in a dynamic and entrepreneurial setting.

Who We Are Dataseat, a proud member of the Verve Group since July 2022, was founded by industry pioneers David Philippson and Dr. Paul Hayton. Our mission is to revolutionize how app marketers manage their programmatic media campaigns. We offer a cutting-edge Bidder or DSP as a service, empowering app marketers to take control of user acquisition and re-engagement through in-house programmatic media buying. Our comprehensive analytics provide clients with crucial insights on fraud, attribution accuracy, and incrementality, supporting marketers in building their in-house business case and optimizing their media strategy. Discover more at www.dataseat.com.

Join Our Data & Science OrganizationAt Deliveroo, we pride ourselves on having a premier data science team dedicated to enhancing the quality of decision-making, both human and machine. Our data scientists collaborate across various departments, including product, business, and platform teams, employing techniques such as analysis, experimentation, causal inference, and machine learning. We leverage data to drive better decisions and enhance data literacy throughout the organization.As a Senior Data Scientist, you will be part of a vibrant community that fosters continuous learning through guest lectures, study groups, mentorship programs, and a rigorous technical review process. Our career paths allow data scientists to advance as technical leaders or people managers, depending on their aspirations.We welcome candidates from diverse backgrounds, all united by a commitment to excellence in data science. Our dedicated diversity committee ensures that we celebrate differences and promote inclusivity within our team.Your primary objective will be to maximize business impact in various areas, tackling critical questions such as:Which markets or cities should we expand into next?How can we encourage positive behavior among our riders?What effect do our exclusive restaurant deals have?How can we optimize our compensation policies to ensure customer satisfaction?What trade-offs should we consider between growth and profitability?How should our pricing strategy vary based on distance and market?What is the ideal selection and variety of restaurants in a specific area?How can we enhance our consumer app to better serve grocery shoppers?The work you do will have a tangible and direct influence on the company's bottom line.

About QuantiumQuantium stands as a global frontrunner in data science and artificial intelligence. Founded in Australia in 2002, our diverse team of over 1,200 professionals operates across 14 locations, combining innovative product and consulting services to empower businesses in extracting value from their data and analytics. We collaborate with some of the largest corporations worldwide to create a smarter, more efficient future.Our Quantium Health UK division specializes in delivering cutting-edge AI, analytics, and digital consulting services tailored for clients in Health, Life Sciences, and HealthTech. Our mission is to leverage data's potential to enhance health outcomes for patients and healthcare providers. As a Data Scientist, you will engage with clients to address their specific needs, develop impactful use cases, utilize advanced analytics and machine learning techniques, and spearhead AI product innovations. Join us during this exhilarating phase of growth and work on transformative projects that make a difference.

About the Role Utility Warehouse is looking for a Data Scientist to join the team in London. This position focuses on analyzing large and varied data sets to uncover insights that support business decisions. The Data Scientist will work closely with colleagues from different departments to build predictive models, run experiments, and strengthen the company’s analytics practice. What You Will Do Analyze complex data sets to identify trends and patterns Develop and refine predictive models Collaborate with teams across the business to support data-driven projects Design and conduct experiments to test hypotheses and improve outcomes Help advance Utility Warehouse’s overall data analytics capabilities Location This role is based in London.

About Checkout.com Checkout.com helps businesses process payments smoothly, supporting companies such as eBay, ASOS, Klarna, Uber Eats, and Sony. The company operates behind the scenes to make global transactions efficient and reliable. Headquartered in London, Checkout.com maintains 19 offices on six continents. Teams focus on performance and innovation, aiming to shape the future of digital payments. Role Overview: Product Data Scientist The Product Data Scientist works within a cross-functional group that includes product managers, designers, and engineers. Insights from data help guide product strategy and define success metrics. Responsibilities include designing dashboards and reports, conducting analyses to spot opportunities for product improvements, and collaborating closely with the team to deliver on product goals. Data Analytics at Checkout.com supports business objectives at every level. In this role, a network of Analytics Engineers and Data Product Managers provides support to help drive growth and impact. Main Responsibilities Lead analytics for a product area: define, measure, and present key metrics, delivering insights that inform decisions. Use data to recommend updates to product roadmaps and identify opportunities for meaningful improvements. Work with Data Analytics and Software Engineering teams to ensure data is collected and modeled to support business insights. Promote a strong data culture within product teams, encouraging innovation and data literacy. Location This position is based in London.