Principal Software Engineer II - Search Internals, Lucene - Elasticsearch

Join Elastic, the leading Search AI Company, as a Principal Software Engineer II focused on Search Internals for Lucene and Elasticsearch. In this pivotal role, you will leverage your extensive expertise to drive the evolution of our core search capabilities, ensuring we deliver an unparalleled search experience. Collaborate within a globally-distributed team of seasoned engineers to enhance our search infrastructure, including indexing and retrieval. You will define the technical vision and roadmap for Elasticsearch, working closely with product teams to shape innovative solutions that meet user needs. Your insights will continuously improve the search experience, making you a key authority in the field.

Role overview As a Senior Software Engineer at 9fin, this position centers on developing and enhancing data-driven systems using Elasticsearch. The main focus is on building scalable search and analytics solutions that support 9fin’s products. Deep experience with Elasticsearch is essential for success in this role. What you will do Design and implement search and analytics features built on Elasticsearch Improve the performance and scalability of existing systems Maintain and evolve the technology stack, emphasizing search functionality Work closely with engineers and stakeholders to deliver solutions aligned with business needs Location This role is based in London.

About Us at GoCardlessGoCardless is a global bank payment solution provider. More than 100,000 businesses, from innovative start-ups to established brands, trust GoCardless for their payment collections via direct debit, real-time payments, and open banking.We facilitate the processing of over US$130 billion in payments annually across more than 30 countries, enabling customers to efficiently manage both recurring and one-off payments without the hassle or high fees. Our AI-driven technology enhances payment success rates and minimizes fraudulent activities. With connectivity to over 2,500 banks through open banking, we empower our customers to make faster and more informed decisions.Headquartered in the UK, we have offices in London and Leeds, along with additional locations in Australia, France, Ireland, Latvia, Portugal, and the United States.At GoCardless, we prioritize supporting you! Our hiring process is designed to be inclusive and accessible. If you require any assistance or adjustments, please reach out to your Talent Partner — we are here for you!Remember, you don’t need to fulfill every requirement to apply. If you are excited about this role, we encourage you to apply!The RoleThis is a contract role with a daily rate lasting for 3 months, with the possibility of extension up to 6 months. You will spearhead the engineering efforts that support the search functionality in our merchant dashboard — the main interface used by thousands of businesses to manage their customers and payments on GoCardless.Search functionality is vital for our merchants. Whether they are searching for a specific customer, tracking a payment, or reconciling transactions, they depend on an efficient search system to access the right information swiftly. You will design and implement a robust, high-performance search solution that is relevant, fast, and resilient at scale.This hands-on engineering position requires close collaboration with our Product Engineering and Platform teams, contributing production-ready code and pairing with engineers throughout your engagement. A key measure of success will be how well the team can maintain and evolve the system after your departure.

Join Algolia, a trailblazer and market leader in AI Search, where we empower over 17,000 businesses to deliver rapid, predictive search and browsing experiences at an internet scale. Every week, we handle more than 30 billion search requests—surpassing the combined total of Microsoft Bing, Yahoo, Baidu, Yandex, and DuckDuckGo.In 2021, we secured $150 million in Series D funding, elevating our valuation to $2.25 billion. This robust foundation allows us to continually invest in our top-tier platform and support exceptional clients like Under Armour, PetSmart, Stripe, Gymshark, and Walgreens.Algolia was designed to enhance user experiences by providing an intuitive search-as-you-type functionality for websites and mobile applications. Our search API is utilized by thousands of clients across 100+ countries, and billions of queries are resolved monthly thanks to the code we deploy daily.We are on the lookout for a Software Engineer to become part of our Metis team. This team manages Metis, our cloud-based scalable architecture for NeuralSearch, our cutting-edge AI search engine that integrates both keyword and vector search capabilities. The Metis system is composed of distributed components that manage the building and storage of indices containing customer data, subsequently querying that data to deliver search results. This role demands a deep understanding of and the ability to address challenges associated with complex distributed systems.Our team comprises engineers from diverse backgrounds, many of whom work remotely. Your unique experiences, knowledge, and perspectives will contribute to our diversity and drive the development of impactful products.

At Algolia, we are proud to be at the forefront of AI Search technology, enabling over 17,000 businesses to provide lightning-fast, predictive search and browsing experiences on a global scale. We handle more than 30 billion search requests each week, surpassing the combined total of Microsoft Bing, Yahoo, Baidu, Yandex, and DuckDuckGo.In 2021, we secured $150 million in Series D funding, elevating our valuation to $2.25 billion. This strong financial backing allows us to continuously enhance our industry-leading platform and serve esteemed clients like Under Armour, PetSmart, Stripe, Gymshark, and Walgreens.Algolia was designed to empower users to offer an intuitive search-as-you-type functionality on their websites and mobile applications. Our search API is utilized by thousands of clients across more than 100 countries, facilitating billions of search queries every month thanks to the code we deploy into production daily.We are on the lookout for a Senior Software Engineer to join our Metis team, which is responsible for the cloud-based scalable architecture of NeuralSearch, our AI-powered search engine that integrates both keyword and vector search capabilities. Metis comprises distributed components that manage the construction and storage of indices containing customer data and querying that data to deliver relevant search results. This role demands a deep understanding of the complexities associated with distributed systems.Our team is composed of engineers, with most working remotely, bringing diverse skill sets and backgrounds. Your unique experiences and insights will contribute to our collective diversity, helping us to create impactful products.

We are seeking a Principal Software Engineer specialized in engineering applications to join our dynamic team at physicsx. In this role, you will lead the design and development of innovative software solutions that empower our engineering teams to achieve exceptional results. Your expertise will drive the implementation of cutting-edge technologies and methodologies, ensuring the highest standards of performance and reliability.As a Principal Software Engineer, you will collaborate closely with cross-functional teams, mentor junior engineers, and contribute to the overall technical strategy of our organization. You will have the opportunity to work on challenging projects that have a significant impact on our business and clients.

Your Impact The Principal Software Engineer plays a pivotal role in shaping and advancing our architectural framework by employing Distributed Domain Driven Design methodologies. This position is crucial for ensuring the resilience and scalability of our systems. You will influence architectural strategies and provide embedded consultation within projects, guiding teams to adopt best practices and effective design patterns. What You'll Do ● Architecture Leadership: Spearhead the definition and evolution of our architecture through Distributed Domain Driven Design principles. Serve as the strategic leader for core Architecture Quality Attributes (e.g., Availability, Performance, Scalability, Security) to guide architectural evaluations. Provide project-specific architectural consultation to advocate best practices, design patterns, and informed buy vs. build decisions.● Platform Capability Enhancement: Aid in prioritizing improvements across feature and data platforms. Enhance the documentation and communication of architectural descriptions through automation and innovative tools. Oversee platform-wide strategies, including naming conventions, protocol standards, and design patterns to ensure continuous value creation.● Effective Communication: Clearly articulate complex technical concepts in both written and verbal formats, tailored to both technical and non-technical stakeholders. Collaborate with various stakeholders to foster consensus when needed, ensuring alignment on architectural choices.

Why VerifoneVerifone has been a pioneering leader in the electronic payment technology sector for over 40 years. Recognized as one of the foremost brands in electronic payment solutions, we rank among the largest providers of payment systems globally.At Verifone, we foster a diverse and dynamic work environment where results-driven employees have ample opportunities to excel. Our collaboration with top retailers, merchants, banks, and third-party partners enables us to innovate and deliver cutting-edge payment solutions worldwide. We are committed to excellence in our products and services, with an unwavering focus on customer satisfaction. Our team of dedicated professionals is at the forefront of the payments industry, driven by experience, innovation, and a bold spirit. Whether we're developing advanced secure payment platforms or exploring new markets for electronic payments, our passion for innovation propels each employee toward personal and professional success.About The RoleWe are looking for a Principal Software Engineer based in London to provide technical leadership for our global payment gateway systems. This role involves designing and evolving core platform capabilities, guiding architectural decisions across microservices, and mentoring engineers while remaining hands-on with critical systems built using Java and Spring Boot.This position is central to shaping the technical direction of systems responsible for processing high-volume, mission-critical financial transactions globally.In this role, you will go beyond mere feature delivery. You will be instrumental in driving architectural decisions, establishing engineering standards, and influencing how teams design, build, and maintain secure, scalable backend systems. Success is characterized by technical leadership, sound judgment in complex trade-offs, and ownership of systems that must operate reliably under real-world loads and regulatory requirements.Collaboration with senior engineering, platform, product, and infrastructure teams will be crucial to ensure our systems scale effectively, remain secure, and uphold the highest standards for availability and performance.

Join Algolia, a trailblazer in AI Search technology, empowering over 17,000 businesses to provide lightning-fast, predictive search and browsing experiences at internet scale. With more than 30 billion search requests processed weekly—four times the volume of Microsoft Bing, Yahoo, Baidu, Yandex, and DuckDuckGo combined—we are setting the standard in the industry.In 2021, we successfully raised $150 million in Series D funding, increasing our valuation to an impressive $2.25 billion. This robust financial backing allows us to continuously enhance our leading platform and serve outstanding clients such as Under Armour, PetSmart, Stripe, Gymshark, and Walgreens.Algolia is designed to enable users to deliver a seamless search-as-you-type experience on their websites and mobile applications. Our search API is utilized by thousands of customers across more than 100 countries, processing billions of search queries each month thanks to our daily production deployments.We are seeking a Senior Software Engineer to join our Metis team, responsible for the cloud-based scalable architecture of NeuralSearch, our AI search engine that integrates both keyword and vector search capabilities. The Metis framework comprises distributed components that coordinate the creation and storage of indices containing customer data, and efficiently query that data to deliver search results. This role involves tackling the complexities inherent in distributed systems.Our team consists of engineers with a variety of skills and backgrounds, many of whom work remotely. Your unique experiences, knowledge, and perspectives will enrich our diversity and contribute to the development of impactful products.

Join Our MissionAt Omnea, we’re transforming enterprise operations by focusing on the often cumbersome procurement process. Imagine a world where a single purchase no longer takes months, requiring 50+ emails and approvals from Finance, Legal, Security, and IT. We aim to change that.Backed by $75M from Khosla Ventures, Insight Partners, and Accel, our AI-driven platform seamlessly connects every stakeholder, step, and system to facilitate quick, safe, and efficient purchasing. Experience automated approvals, real-time supplier risk assessments, and complete visibility into spending—all from one centralized location.With a $7B+ untapped market, our growth trajectory speaks volumes. We have achieved a tenfold increase in Annual Recurring Revenue (ARR), reaching double-digit millions in just 18 months, and have earned the trust of global enterprises like Spotify, MongoDB, Monzo, and Albertsons. We are proud to be recognized as the 4th fastest growing startup in Europe.Our experienced team includes former members of Tessian, the cybersecurity tech firm backed by Sequoia, Balderton, and Accel, who have successfully scaled unicorns and launched world-class products. You will collaborate with industry leaders including Ben, Abs, Sabrina, and Rebe.Your RoleWe are on the lookout for an outstanding, product-focused full-stack software engineer to join our engineering team. As we aim to scale from our current double-digit customers to over 200 enterprise clients and significantly increase our revenue over the next 2–3 years, your contributions will be vital in driving our product, team, and company growth as we transition from a 'start-up' to a 'scale-up'.You will be joining us at a crucial moment. We recently secured $50M in Series B funding from Khosla Ventures, Insight Partners, and Accel.

Join Wayve Technologies as a Principal Application Software Engineer and be part of a pioneering team that is transforming the future of autonomous driving. This role involves leading software application development, collaborating closely with cross-functional teams, and driving innovative solutions to real-world challenges in the automotive industry.The ideal candidate will possess extensive experience in software engineering, a strong understanding of algorithms, and a passion for cutting-edge technology. You will play a critical role in enhancing our software architecture and ensuring the scalability and performance of our applications.

Why Choose Deliveroo?At Deliveroo, our mission is to revolutionize the shopping and dining experience by delivering your favorite food and products right to your doorstep. We bridge the gap between consumers, restaurants, shops, and riders, making it easier and more enjoyable to access what you love, when you want it.As a technology-driven organization, we are at the forefront of one of the fastest-growing industries globally. Although we are a compact team, our impact is significant, as we tackle some of the most compelling challenges in our sector. We prioritize speed, independence, and innovation, continually seeking fresh ideas.Joining Deliveroo offers an exceptional opportunity to build a meaningful career centered on impact—both on your personal development and our company as we scale. You can leave your mark while contributing to the positive effects we create in our marketplace and communities.About the InternshipIn your role as a Software Engineer Intern at Deliveroo, you will implement and manage technological solutions that enhance the experiences of our restaurants, riders, and customers. From designing user-friendly interfaces to developing scalable backend systems, our goal is to deliver reliable and high-performance technology that delights our users.Our 12-week internship program immerses you fully within your team, allowing you to develop, maintain, and ship products that make a real difference. You will have the chance to collaborate with your team to solve genuine problems for our customers, directly influencing our business.Candidates must possess the legal right to work in the U.K. to be eligible for this position. The internship program for 2026 will take place in person at Deliveroo's London headquarters at Cannon Bridge House.

Join CoreWeave as a Principal Engineer!At CoreWeave, we are redefining the cloud landscape for AI innovation. Our platform is tailored for trailblazers, offering cutting-edge technology and a collaborative environment designed to empower innovators to construct and expand AI solutions with assuredness. Serving leading AI labs, startups, and global corporations, we blend exceptional infrastructure performance with extensive technical know-how to expedite breakthroughs and transform compute power into actionable capabilities. Since our founding in 2017, we have proudly transitioned to a publicly traded entity (Nasdaq: CRWV) as of March 2025. Discover more at www.coreweave.com.As a Living Wage accredited Employer, we prioritize fair compensation for all our employees.

At Intercom, we're revolutionizing customer service through our advanced AI solutions. Our flagship AI agent, Fin, empowers businesses to deliver exceptional customer experiences, ensuring they're always available to assist users. When combined with our Helpdesk, Fin forms the Intercom Customer Service Suite, a comprehensive solution for addressing complex customer queries that require a personal touch.Since our inception in 2011, we have gained the trust of nearly 30,000 businesses globally, setting the standard for customer service excellence. Our commitment to innovation drives us to push boundaries and deliver unparalleled value to our clients.What’s the opportunity?As a Principal Engineer at Intercom, you'll take the lead in defining and executing key strategic initiatives. This role offers you the autonomy to impact the engineering organization significantly. You'll be responsible for developing both back-end and front-end systems, collaborating closely with designers, product managers, researchers, and data analysts. Additionally, you'll mentor and coach fellow engineers while partnering with Group Engineering Managers on technical strategy and leadership.What will I be doing?In this role, you will:Utilize your domain expertise to lead pivotal projects within our R&D organization.Provide insights on project progress, risks, and challenges to guide resource allocation and prioritization effectively.Contribute to our technical architecture, ensuring our systems scale to meet growing customer demands.Prioritize agility alongside scalability and availability, with a focus on continuous deployment and incremental releases.Engage in all software development phases, including ideation, prototyping, design, and implementation, balancing hands-on development with architectural leadership.Leverage state-of-the-art tools to enhance productivity and streamline problem-solving.

Join us at Docker, where we revolutionize app development, allowing developers to concentrate on what truly matters. Our remote-first global team thrives on innovation and enhancing the developer experience. With over 20 million monthly users and 20 billion image pulls, Docker stands as the premier tool for building, sharing, and running applications—trusted by both startups and Fortune 100 companies. As we rapidly expand, we're just getting started. Come aboard and enjoy this exciting journey!We are seeking a Principal Software Engineer (Docker Agents) to join our AI engineering team to shape the future of containerized AI agents. Docker containers provide the ideal environment for hosting and executing AI agents, ensuring isolation, portability, and reproducibility. You will work on our open-source project, cagent (https://github.com/docker/cagent), and enhance it to empower developers in building, deploying, and scaling intelligent agents utilizing Docker’s container technology.This is a unique opportunity to influence how developers harness containers for AI agents on a large scale. You will establish the technical vision, spearhead architectural decisions, and collaborate with engineers and leaders across Docker to integrate containerized agent capabilities into the developer experience.

Join Runna as a Senior Software Engineer II, where you'll play a pivotal role in enhancing our software solutions. You will collaborate with cross-functional teams to design, develop, and implement robust applications that meet our customers' needs. Your expertise will help us push the boundaries of technology, ensuring our products remain at the forefront of the industry.

Company OverviewDeductive AI is pioneering the development of the world's first real-time reasoning engine designed to identify and mitigate large-scale software outages. By employing advanced reasoning techniques on distributed systems, code, and statistical anomalies, we analyze vast amounts of telemetry data—including metrics, logs, traces, and events—in real-time. Our accomplished team boasts decades of experience from industry leaders such as Databricks, Facebook, Thoughtspot, Google, Splunk, and Amazon. Backed by top-tier venture capital firms, we are well-positioned for growth and innovation.Internship OverviewWe are looking for innovative interns to join our team and engage with cutting-edge technology. You will tackle fascinating challenges at the intersection of artificial intelligence, code understanding, and data analytics. Your work will involve distributed systems, the development of AI agents, and the fine-tuning and benchmarking of Large Language Models (LLMs).This is a paid, on-site internship based in Camden, London. As a Software Engineer Intern at Deductive AI, you will have the opportunity to contribute to the next generation of foundational code and data processing systems that can reason over extensive datasets, both structured and unstructured. We are committed to aligning projects with your skillset and preferences.

About Anthropic Anthropic builds AI systems with a focus on reliability, interpretability, and steerability. The company’s mission centers on making AI safe and beneficial for both individuals and society. The team includes researchers, engineers, policy experts, and business leaders working together to advance responsible AI development. Role Overview: Software Engineer, Safeguards Foundations – Internal Tooling The Safeguards team at Anthropic is responsible for detecting, reviewing, and addressing potential misuse of the company’s AI models. Within this team, the Foundations group develops the infrastructure, platforms, and internal tools that support these safeguards across the organization. This role focuses on improving internal tooling for human review. The work covers case management, labeling workflows, investigative processes, and enforcement interfaces used daily by analysts and policy specialists. Although these tools operate behind the scenes, their reliability and clarity directly affect how quickly Anthropic can spot harmful behaviors, make enforcement decisions, and provide feedback for model training. The position involves close collaboration with Trust & Safety operations, policy, and detection-engineering teams. The goal: turn complex operational needs into robust, maintainable software that supports Anthropic’s safety mission. What You Will Do Enhance and maintain internal tools for human review, including case management and enforcement interfaces Work across the stack to deliver reliable, user-friendly products for internal stakeholders Partner with operations, policy, and engineering teams to understand workflows and translate them into effective software solutions Support the organization’s ability to detect and respond to AI misuse efficiently Location London, UK

Internship Overview Wexler is seeking a Software Engineering Intern to join its London team. This is a hands-on role where interns work closely with experienced Software and Machine Learning Engineers, contributing directly to the company’s agent infrastructure and product innovation. The work impacts legal professionals who depend on Wexler’s technology every day. This internship is designed for students set to graduate in 2026 or strong second-year students from top UK universities, ideally studying Computer Science or a related field. A genuine interest in building, learning, and applied AI is important. About Wexler Wexler specializes in Legal AI, focusing on solutions tailored to the specific workflows of legal professionals. The company addresses the slow adoption of AI in the legal sector by offering targeted, precise tools rather than general-purpose platforms. Wexler’s approach has earned positive feedback for its attention to detail and commitment to supporting the needs of legal practitioners. What You Will Do Develop and improve Wexler’s agentic infrastructure. Work with the technical team on new projects that extend product capabilities. Help build user interfaces that make complex legal workflows accessible. Collaborate with AI engineers to bring LLM features into production systems. Participate in architecture discussions and learn best practices from experienced engineers. Tackle challenges such as delivering smooth user experiences, scaling performance, and upholding enterprise security standards. Technical Skills Back-end: Solid experience with Node.js, TypeScript, or Python (preferably both). Ability to write clean, testable server-side code. Databases: Familiarity with relational databases, especially PostgreSQL. Understanding of schema design and querying.

Join Pipedrive as a Search Engine Marketing (SEM) Manager and lead our digital marketing initiatives to enhance our online presence and drive conversions. In this role, you will be responsible for developing and executing effective SEM strategies, managing campaigns across various platforms, and analyzing performance metrics to optimize results. Your expertise will help us reach new heights in our marketing endeavors.