Senior Backend Engineer - Recommendation Systems (Contractor)

Become a vital member of the OPPO US Research Center's dynamic team, where you will spearhead the development and enhancement of backend services for our high-traffic products, including the App Store, Global Search, and Game Center. Your contributions will ensure that millions of users enjoy a seamless experience every day. Key Responsibilities:Architect an…

About xAIAt xAI, our mission is to develop AI systems that genuinely comprehend the universe and support humanity's quest for knowledge. We pride ourselves on having a compact, highly driven team dedicated to engineering excellence. Our environment is perfect for individuals who relish challenges and flourish through curiosity. We embrace a flat organizational structure where every employee is encouraged to be proactive and to directly contribute to our mission. Leadership opportunities are awarded to those who demonstrate initiative and consistently achieve outstanding results. Strong work ethic and effective prioritization skills are key attributes we value. Additionally, all team members must possess excellent communication skills to share insights and knowledge clearly and concisely with their colleagues.About the RoleWe are looking for talented Applied Engineers to join a pivotal project that serves around 600 million users monthly. This is a unique opportunity for professionals with an engineering or scientific background to leverage their expertise in recommendation systems, ranking algorithms, search technologies, and more. You will be at the crossroads of cutting-edge AI development and tangible real-world impact, enhancing our ability to connect users with relevant content, accounts, and experiences.What You'll DoDesign and architect innovative recommendation algorithms for diverse product surfacesUtilize xAI’s extensive infrastructure and AI tools to significantly enhance user experiencesDevelop data pipelines and training jobs that continuously adapt from product dataIterate and refine algorithms using real-time user feedback through experimentationEnsure the scalability and efficiency of machine learning systemsWho You AreFamiliarity with data infrastructure technologies such as Kafka, Clickhouse, and SparkProven experience in implementing recommender systems and/or deep learning applications at scaleProficient in one or more deep learning software frameworks, such as JAX or PyTorchExceptional candidates may have experience in writing CUDA kernels

Pinterest is looking for a PhD Fall Machine Learning Intern with a focus on visual, multimodal, and recommender systems. This internship centers on supporting advanced machine learning projects alongside skilled engineers and researchers. Role overview The position involves contributing to ongoing research and development in machine learning. Interns will have the chance to work on projects that explore visual understanding and recommendation technologies, learning from experienced team members throughout the process. Collaboration Expect to work closely with engineers and researchers who specialize in machine learning. The environment encourages sharing ideas and building solutions that impact Pinterest’s products. Locations San Francisco, CA, US Palo Alto, CA, US Seattle, WA, US New York, NY, US

Join our innovative team at vinci4d as a Backend Engineer specializing in Data Systems and APIs. In this role, you will play a crucial part in designing, implementing, and maintaining robust data systems that power our applications. You will collaborate with cross-functional teams to build scalable APIs that enhance user experiences and support our mission to deliver cutting-edge technology solutions.

Senior Backend Software EngineerDepartment: Engineering | Location: Palo Alto HQ | Type: Full-time, On-siteAbout the RoleAt Pika, we are seeking a talented Senior Backend Software Engineer to play a pivotal role in enhancing our core infrastructure that supports our innovative products. You will be instrumental in the design and development of robust, scalable backend systems, overseeing everything from API design and service architecture to real-time messaging infrastructures and platform integrations. This is a high-stakes position where your decisions will directly influence the experiences of millions of users interacting with Pika.In this senior position, you will also elevate the team’s capabilities through architecture guidance, comprehensive code reviews, and mentoring opportunities for junior engineers.What You'll Do• Design and develop scalable backend services that drive Pika's web, mobile, and multi-platform offerings.• Manage backend logic from end-to-end, including database modeling, API design, infrastructure decisions, and ensuring production reliability.• Create and implement real-time systems, including WebSocket connections, event-driven architectures, and messaging queues for low-latency communication.• Optimize infrastructure to enhance throughput, reduce latency, and ensure reliability as Pika continues to grow.• Enhance internal tooling and automate operational processes to streamline team workflows.• Lead technical decisions by drafting RFCs, assessing trade-offs, and building consensus within the engineering team.• Mentor and guide engineers through code reviews, architectural advice, and collaborative programming sessions.• Troubleshoot, optimize, and future-proof systems to handle increased scale.What We're Looking For• A minimum of 5 years of backend engineering experience, specifically in building production services at scale.• Expertise in modern backend technologies (Node.js, Python, Go, etc.) and frameworks (Express, FastAPI, etc.).• A solid understanding of distributed systems, including event-driven architectures, message queues, and service-to-service communication.• Profound knowledge of database design and operations (SQL, NoSQL, data modeling, performance tuning).• Familiarity with APIs, cloud infrastructure (AWS, GCP), Kubernetes, and CI/CD workflows.• Experience in building real-time systems using WebSockets, long-polling, and pub/sub patterns.• Excellent debugging and observability skills; you can trace problems across services efficiently.• A proactive ownership mentality — you identify issues and implement solutions without waiting for specifications.• Strong communication skills and a collaborative mindset.Nice to Have• Experience with AI/LLM integration (model orchestration, token management, prompt routing).• Familiarity with multi-tenant SaaS platforms or multi-platform products.• Experience building internal tools or automation pipelines.• Previous experience in a startup environment, comfortable with ambiguity and rapid movement.

About xAIAt xAI, we are dedicated to developing advanced AI systems that comprehend the complexities of the universe and assist humanity in its quest for knowledge. Our team is compact, highly driven, and committed to engineering excellence. We value individuals who seek challenges and embrace curiosity. Operating within a flat organizational structure, we expect all employees to be proactive and directly contribute to our mission. Leadership opportunities are given to those who demonstrate initiative and consistently deliver outstanding results. A strong work ethic and exceptional prioritization skills are essential. Effective communication skills are a must, allowing team members to convey knowledge clearly and accurately.About the RoleAre you a strategic thinker and adept problem-solver with extensive knowledge of contemporary IT systems? We are on the lookout for a Senior IT Systems Engineer who is enthusiastic about spearheading automation efforts, advancing our enterprise workforce identity and access management (IAM), and designing scalable, secure SaaS integrations. In this pivotal individual contributor role, you will collaborate closely with IT Services, Information Security, HR, Finance, and Engineering teams. You will be responsible for the deployment and integration of vital IT systems, serving as the primary escalation point for intricate IT outages and architectural issues, and guiding the development of our hybrid infrastructure to accommodate swift business growth.

About ALSO.At ALSO, we are pioneers in electric mobility, originally nurtured as part of Rivian. Our dedicated team of creators, innovators, and visionaries is committed to revolutionizing urban transportation through the development of innovative, vertically integrated small electric vehicles (EVs). We aim to tackle the mobility challenges of today and tomorrow by inspiring individuals to choose ALSO, thus replacing traditional car, truck, and SUV journeys with more affordable, enjoyable, and significantly efficient alternatives.We are currently seeking a Senior Staff Systems Engineer who will be instrumental in shaping and supporting the requirements and feature development for our cutting-edge electric mobility vehicles!Your ResponsibilitiesLead the architectural design and requirements development for a cross-functional micromobility vehicle platform, collaborating with Electrical Engineering, Firmware, and Product Design teams, ensuring seamless alignment from conceptualization through to validation.Act as the primary technical liaison between customers and ALSO leadership, capturing product intent and translating it into coherent system artifacts such as user stories, CONOPS, and use cases.Establish and manage requirements at the system, subsystem, and hardware module levels, working closely with internal stakeholders in areas such as:Low-voltage electronicsBattery and energy storage systemsDrivetrain and actuatorsConnectivity and telematicsHuman–Machine Interfaces (HMI)Sensor systemsEnsure comprehensive end-to-end traceability across user stories, features, system requirements, subsystem requirements, and verification/validation test cases.Develop and maintain system architectures for distributed embedded controllers, including interface definitions, communication protocols, functional decomposition, fault detection, and system-level robustness.Collaborate effectively with software engineers, electrical engineers, product designers, product managers, and UI/UX teams to drive CONOPS, activity diagrams, feature design, development, and validation.

This is a hybrid position based in our Palo Alto office, requiring in-office attendance on Tuesdays and Thursdays.Why This Role Stands Out?Join a rapidly expanding team at Grindr, where our user base has surged by 30% in the past year! We are in search of a seasoned Backend Engineer who is enthusiastic about building, testing, and deploying robust features alongside our Product team. This is your chance to tackle intriguing challenges, engage with cutting-edge technologies, collaborate with a talented team, and make significant contributions.Key Responsibilities:Become an integral part of a backend team of over 10 engineers, focusing on vital features that cater to millions of active daily users.Lead projects and mentor fellow engineers in implementing new functionalities while closely collaborating with product and design teams.Take ownership of designing and developing Grindr’s backend services within a stable and scalable microservices architecture.Work closely with Product Managers, Designers, and fellow Engineers to refine feature design and functionality.Enhance Grindr's platform using tools such as Redis, Postgres, and Kafka on AWS services.Drive innovation through data-informed decisions regarding new technologies, architectures, and workflows.Ensure high availability of Grindr’s platform by utilizing distributed systems and infrastructure engineering, while playing a pivotal role in optimizations, cost reduction, and incident management.Guide and mentor team members through pairing sessions, code reviews, and architecture discussions.What We Value in You:A minimum of 7 years of experience as a Software Engineer with a focus on Backend Systems (Service APIs, Data Processing, Messaging Services).Proven experience in designing and implementing large-scale systems for high load and data consistency within a microservice architecture.Expertise in designing systems that leverage Cloud Services, preferably AWS.A strong passion for software and system testing.In-depth understanding of concurrency concepts and associated trade-offs.A natural curiosity for troubleshooting and comprehending systems end-to-end.

Join us in revolutionizing healthcare. At Qualified Health, we are pioneering the possibilities of Generative AI within the healthcare sector. Our advanced infrastructure establishes crucial guidelines for safe AI governance, tailored agent development, and real-time monitoring of algorithms, collaborating with prominent health systems to effect real change. This role transcends a mere job; it's a chance to forge the future of AI in healthcare, tackle intricate challenges, and create a meaningful impact on patient care. If you are driven, innovative, and eager to accelerate progress, we would be thrilled to have you on our team. Be part of shaping the future of healthcare.

Company OverviewAt Flow, we are redefining the essence of living, working, and connecting. Flow transcends traditional real estate; we are a dynamic brand, a cutting-edge technology platform, and a comprehensive operational ecosystem that encompasses condominiums, hotels, multifamily residences, and office spaces. Our vision is to create a new living experience that is adaptable, interconnected, and designed to foster authentic community and significant value for our residents.Our mission revolves around the concept of oneness: prioritizing the needs and experiences of our residents while nurturing connections with their neighbors and the natural environment. By placing people at the heart of everything we do, we are cultivating vibrant, human-centered communities where life, work, creativity, and leisure harmoniously coexist.Position SummaryAs a Senior Backend Software Engineer at Flow, you will play a pivotal role in developing robust backend systems to support our expanding operations. You will collaborate with cross-functional teams to design and implement secure, scalable, and resilient services. This position requires a proactive approach to problem-solving, a keen eye for optimization, and a strong sense of ownership over your work.We believe that collaboration enhances success. All roles at Flow require an onsite or in-office presence.

Pivotal stands at the forefront of the dynamic eVTOL (electric Vertical Takeoff and Landing) aircraft industry. We specialize in the design, development, and manufacturing of lightweight eVTOL aircraft, including our iconic BlackFly, recognized as the world's first light eVTOL to successfully conduct manned missions and enter the consumer market.Our aircraft are engineered to be efficient, compact, and user-friendly, catering to a diverse range of applications spanning consumer use, public service, and defense sectors. With over a decade of successful flights under our belt, our innovative tilt-aircraft architecture and scalable platforms are setting the stage for the future of mobility. Last year, we unveiled our next-generation aircraft, the Helix, which is poised for general release and scalable production by early 2026.In today's technology landscape, mobility is a highly coveted investment area. Join us at Pivotal, where the timing is perfect, and the strategy is sound. If you're ready to embark on this exciting journey, we welcome you to be a part of our exceptional team and grow alongside us.As a valued member of our Firmware Engineering team, you will play a critical role in driving the development and maintenance of the pilot display systems used in our eVTOL aircraft.

Join Protegrity, a trailblazer in data protection, as we harness the power of AI and quantum-resistant cryptography to revolutionize data security across diverse environments including cloud-native, hybrid, on-premises, and open-source systems. By utilizing cutting-edge cryptographic techniques such as tokenization, format-preserving encryption, and quantum-resilient methods, we aim to make sensitive data not only secure but also accessible and trustworthy.At Protegrity, you will collaborate at the forefront of innovation, making significant contributions to the industry while working with a team of exceptional professionals. Together, we are reshaping the future of data security, empowering organizations to flourish in a GenAI landscape where data is the most valuable asset. If you are prepared to influence the future of data security, Protegrity welcomes you.We are seeking an experienced, motivated, and inquisitive DevOps Software Engineer with expertise in backend API development, microservices deployed on Kubernetes, Generative AI (GenAI), and Large Language Models (LLMs). A strong dedication to data security, privacy, and safety is essential - WE WANT YOU!In this role, you will focus on the integration and maintenance of GenAI backend microservices within Kubernetes, developing and maintaining engineering solutions for products that ensure the safe and secure use of GenAI by our customers.

DataHub is a pioneering AI & Data Context Platform utilized by over 3,000 leading enterprises, including giants like Apple, CVS Health, Netflix, and Visa. Developed in collaboration with a vibrant open-source community comprising over 13,000 members, DataHub's metadata graph offers profound context about AI and data assets, ensuring unparalleled scalability and extensibility.Our enterprise SaaS product, DataHub Cloud, provides a fully managed solution equipped with AI-driven discovery, observability, and governance capabilities. Organizations depend on DataHub's offerings to expedite their data investments' return, guarantee AI system reliability, and enforce unified governance, allowing AI and data to harmonize and restore order to data chaos.The ChallengeAs AI and data products become integral to business operations, enterprises grapple with a metadata crisis:A lack of a unified approach to tracking the intricate data supply chain supporting AI systems.Engineering teams face hurdles in data discovery, lineage, and governance.Organizations require machine-scale metadata management beyond mere human-browsable catalogs.Why This MattersThis is where infrastructure meets impact. The metadata layer you create will directly fuel the next generation of AI systems at an unprecedented scale. Your contributions will determine how securely and efficiently thousands of organizations deploy AI, influencing millions of users globally.The RoleWe seek an outstanding Backend Engineer to spearhead the development of DataHub's Platform framework – the backbone that connects various data systems and drives our metadata collection functionalities.You’ll BuildScalable, fault-tolerant ingestion systems for enterprise-grade metadata.Clean, intuitive APIs for our connector ecosystem.Event-driven architectures for real-time metadata processing.Schema mapping between diverse systems and DataHub's unified model.Versioning systems for AI assets (training data, model weights, embeddings).

Role Overview:Join us as a Backend Software Engineer at nace.ai, where you will play a critical role in crafting, deploying, and maintaining the comprehensive infrastructure for our cutting-edge AI systems. Your primary focus will be on designing resilient backend services, developing intuitive and high-performance user interfaces, and ensuring the flawless integration of LLM-based AI Agents. Your contributions will effectively bridge frontend user experiences with backend scalability and core AI infrastructure, significantly enhancing system efficiency, reliability, and user-facing functionalities.Key Responsibilities:Design, develop, and maintain scalable full-stack components, encompassing both frontend applications (utilizing frameworks such as React, Vue, or Angular) and robust backend services (using Python, Go, or Node.js).Create and implement APIs and data pipelines that enable seamless deployment and interaction of advanced AI Agents along with large-scale data processing workflows.Contribute to the evolution of core AI agent frameworks, focusing on essential features like tool integration, memory systems, and planning/orchestration modules.Develop and implement methodologies for evaluating AI Agents to rigorously assess, benchmark, and monitor agent performance, reliability, and safety in live environments.Oversee and optimize cloud infrastructure (e.g., AWS, GCP, Azure) to ensure high availability, cost-effectiveness, and scalability for both application layers and the underlying AI compute resources.Engage actively in design discussions, code reviews, and cross-functional collaboration to deliver high-quality, production-ready solutions across the entire tech stack.

Role Overview Pylon is hiring a Backend Engineer focused on API development in Palo Alto. This role centers on designing, building, and improving APIs that support our services and applications. What You Will Do Create and maintain APIs to power new and existing features Work with teams across engineering, product, and design to ensure APIs integrate smoothly Optimize API performance and reliability as our products grow Support project goals by contributing technical expertise in backend systems

Backend Software EngineerConfluera is an innovative cybersecurity startup backed by Series B funding, dedicated to safeguarding the cyber landscape. Our mission is to fortify enterprises today to ensure a more secure tomorrow. We provide a comprehensive solution that enhances visibility across cloud environments, empowering cybersecurity leaders with real-time attack prevention capabilities.Key Responsibilities- Design and construct distributed systems capable of processing vast amounts of data.- Develop, maintain, and optimize APIs and systems for scalable product enablement.- Create advanced models and features to improve anomaly detection accuracy.- Collaborate and communicate effectively with Product, Design, and Engineering teams.- Rapidly develop and iterate on solutions while upholding high-quality standards.Required Qualifications- Proficiency in programming languages such as Java and Python.- Experience with streaming platforms like Kafka.- Familiarity with stream processing frameworks, including Spark.- Understanding of distributed systems architecture.Preferred Qualifications- Prior experience working with streaming and stream processing systems (Kafka, Spark, etc.).- Knowledge in building ETL pipelines.- Experience delivering and maintaining large-scale production systems.- Leadership experience in technical projects.Educational Background- A Bachelor's or Master's degree in Computer Science, Computer Engineering, or a related field, or equivalent professional experience.

Our VisionAt Tinder, we believe in the excitement of forging new connections. Our mission is to keep the spark of human interaction alive, empowering millions across the globe to discover meaningful relationships. With a community of tens of millions of users, hundreds of millions of downloads, over 2 billion swipes, and more than 20 million matches daily, our influence spans across 190+ countries and is continually expanding.We collaborate to tackle intricate challenges. Beneath the surface simplicity of each match lies a profound exploration of human relationships, behavioral science, AI and ML, safety online and offline, cultural diversity, and the complexities of love and connection.Internship DurationThis internship will take place from June 1 to August 28, 2026.Work EnvironmentThis is a hybrid position that requires in-office collaboration three days a week in either Los Angeles or Palo Alto, California.Role OverviewAs a Backend Engineering Intern at Tinder, you will work closely with experienced engineers, contributing innovative solutions to enhance our backend infrastructure. We are committed to refining our architectural design and adopting cutting-edge technologies to continually evolve our application and redefine how people connect globally.

Role Overview Pylon is looking for a Backend Engineer focused on integrations to help expand connections with a range of platforms. This role centers on designing and building backend systems that support seamless integrations and reliable data flows. What You Will Do Develop backend solutions that enable integrations with external services and platforms Collaborate with teams across engineering, product, and other functions to deliver integration features Contribute to the stability and scalability of backend services that support Pylon’s business Location This position is based in Palo Alto.

About the Role Pylon is looking for a Backend Engineer focused on Underwriting to help build and improve backend systems that support our underwriting operations. This position is based in Palo Alto. What You Will Do Work closely with teams across the company to design, implement, and refine backend systems for underwriting Develop solutions that prioritize scalability and efficiency Align backend architecture with Pylon’s business objectives

xAI Inc. develops AI systems aimed at deepening understanding of the universe and supporting learning. The team operates with a focus on engineering quality, open knowledge sharing, and direct contributions. Initiative is encouraged, and leadership grows from consistent, high-quality work. Clear communication, a strong work ethic, and effective task prioritization are core values. Role overview The Backend Engineer - API will build and maintain scalable, reliable production infrastructure for xAI’s backend systems. The primary backend stack uses Rust, and experience with compiled languages such as Rust, C++, or Go is especially valued. What you will do Design and operate production infrastructure that supports xAI’s backend systems at scale Work with Rust (preferred), C++, Go, or similar compiled languages Share technical insights and collaborate closely with teammates Tackle engineering challenges proactively and take ownership of solutions Prioritize tasks and deliver results independently Requirements Experience designing and operating scalable production infrastructure Hands-on knowledge of Rust, C++, Go, or similar compiled languages Strong communication skills Proactive problem-solving and ownership mindset Ability to prioritize and work independently Location This position is based in Palo Alto, CA.