Senior Software Engineer (ML QA)

Graphcore

ABOUT THE JOB Validate the ML stack that turns accelerator hardware into trusted AI performance. This role sits where modern ML models meet Graphcore’s software and hardware stack. You will test, benchmark and validate complex systems before they reach customers. Your work will expose regressions, correctness issues and performance limits across frameworks, models and execution environments. You will help teams understand what is working, what is breaking and why. You will run open source models, build automated benchmarking pipelines and create targeted tests for low level ML behaviour. That includes numerical precision, quantisation, attention mechanisms, distributed execution and model subgraphs. This is a role for someone who wants to stay close to how AI systems really work. You will not design new models, but you will make them run reliably on ambitious infrastructure. THE TEAM AND CULTURE The ML QA team is where Graphcore’s ML software stack comes together for validation. Work spans unit tests, full model benchmarks, distributed workloads, simulators, emulators and hardware targets. Engineers are expected to take ownership, question assumptions and improve how testing is done. The team moves quickly, but decisions are grounded in evidence, benchmark data and technical discussion. You will work closely with software, infrastructure and hardware teams. Squads organise around priorities, with space for engineers to shape roadmaps and raise the quality bar. WHAT WE’RE LOOKING FOR · Strong experience in Machine Learning or ML-adjacent software engineering roles. · A solid grasp of neural networks, training, inference, numerical precision and performance trade-offs. · Hands-on experience with PyTorch, TensorFlow, JAX, Triton or similar ML frameworks and tools. · Strong Python skills for automation, experimentation, benchmarking and reporting. · Experience designing, running and analysing ML benchmarks or model experiments. · Confident debugging skills in Linux, with curiosity about model behaviour and system performance. BENEFITS · Unlimited annual leave · Up to 5% matched pension · Phantom equity – share in Graphcore’s success · True flexibility in how and where you work · Office spaces designed for collaboration · Free food and an on-site barista · Health cash plan · Income protection · Life assurance · Along with other benefits you can choose from (private medical insurance, dental plan etc) We welcome people from all backgrounds and experiences and are committed to building an inclusive environment where everyone can do their best work. We’re an equal opportunity employer and recognise that everyone brings different strengths and perspectives. If you need any adjustments during the interview process, just let us know - we’re happy to support you. JOIN THE TEAM AT GRAPHCORE Graphcore is one of the world’s leading innovators in Artificial Intelligence compute. It is developing hardware, software and systems infrastructure that will unlock the next generation of AI breakthroughs and power the widespread adoption of AI solutions across every industry. As part of the SoftBank Group, Graphcore is a member of an elite family of companies responsible for some of the world’s most transformative technologies. Together, they share a bold vision: to enable Artificial Super Intelligence and ensure its benefits are accessible to everyone. Graphcore’s teams are drawn from diverse backgrounds and bring a broad range of skills and perspectives. A melting pot of AI research specialists, silicon designers, software engineers and systems architects, Graphcore brings together deep expertise to solve complex problems and deliver meaningful progress in AI compute. If you want to validate the systems behind next generation AI compute, we’d love to hear from you. Apply now to help build what comes next.

Flo Health

500M+ downloads. 80M+ monthly users. A decade of building – and we’re still accelerating. Flo is the world’s #1 health & fitness app worldwide on a mission to build a better future for female health. Backed by a $200M investment led by General Atlantic, we became the first product of our kind to reach a $1B valuation in 2024 – and we’re not slowing down. With 7M paid subscribers and the highest-rated experience in the App Store’s health category, we’ve spent 10 years earning trust at scale. Now, we’re building the next generation of digital health – AI-powered, privacy-first, clinically backed – to help our users know their body better. The job We are looking for a Senior Software Engineer with deep expertise in AI/ML infrastructure to join our AI Platform team and help build the GenAI platform that powers every AI feature at Flo. You will bridge core infrastructure, data engineering, and LLM development to deliver production-grade medical safety judges, fine-tuning pipelines, evaluation frameworks, and real-time personalisation. The team operates 60+ LLM-based evaluation judges, develops proprietary fine-tuned health models, and maintains active partnerships with Databricks, Google, OpenAI, Anthropic, and AWS. What you’ll do * LLM Judge Ecosystem: build and scale Judge-as-a-Service, prompt registries, calibration pipelines, and evaluation orchestration using MLflow 3.x * Fine-Tuning and Serving: develop LoRA/SFT/preference optimisation pipelines for health-domain models (Llama, Gemma, MedGemma) and manage model serving at scale on Databricks * Data and Evaluation Pipelines: build synthetic Q&A generation, golden test sets, reward function engineering, and Delta table schemas in Unity Catalog for reliable, reproducible evaluation data * Infrastructure: maintain Terraform-managed AWS infrastructure (EKS, S3, IAM), Databricks AI Gateway, and CI/CD pipelines (GitHub Actions) with evaluation gates and progressive rollout * Cross-Functional Impact: collaborate with Product, Security, Analytics, and Medical teams, develop internal SDKs and APIs consumed by 5+ teams, and engage directly with technology partners on pre-release capabilities Experience and skills Must have: * Engineering maturity: 7+ years of software engineering, 4+ years focused on ML/AI platforms * LLM experience: recent hands-on work with at least one of: fine-tuning, prompt engineering, LLM evaluation, or model serving * Technical stack: strong Python across production services and data pipelines, data engineering fundamentals (Spark, Delta tables, Parquet) * Platform and infrastructure: Databricks (MLflow, Unity Catalog, Model Serving), AWS (EKS/Kubernetes, IAM), Terraform, GitHub Actions * Cross-domain flexibility: comfort working across ML, data engineering, and infrastructure. You don’t need to be expert in all three, but you contribute wherever the team needs it Nice to have: * LLM evaluation frameworks (judges, graders, calibration methodology) or fine-tuning techniques (LoRA, RLHF/DPO, model distillation) * ML data engineering: synthetic data generation, evaluation dataset design, annotation pipelines * Healthcare, regulated industry, or safety-critical AI systems experience * Prompt optimisation frameworks (DSPy or similar), feature stores (Tecton) #LI-KP1 #LI-Hybrid  Annual Salary Range (ranges may vary based on skills and experience) £120,000—£150,000 GBP How we work We’re a mission-led, product-driven team. We move fast, stay focused and take ownership – from brief to build to impact. Debate is encouraged. Decisions are shared. We care about craft, ship with purpose, and always raise the bar. You’ll be working with people who take their work seriously, not themselves. It takes commitment, resilience, and the drive to keep going when things get tough. Because better health outcomes are worth it.  What you'll get We support impact with meaningful reward. Here’s what that looks like: * Competitive salary and annual reviews * Opportunity to participate in Flo’s performance incentive scheme * Paid holiday, sick leave, and female health leave * Enhanced parental leave and pay for maternity, paternity, same-sex and adoptive parents * Accelerated professional growth through world-changing work and learning support * In-person collaboration and work in a hybrid model, with 3 days per week spent in the office * 5-week fully paid sabbatical at 5-year Floversary * Flo Premium for friends & family, plus more health, pension and wellbeing perks Diversity, equity and inclusion Our strength is in our differences. At Flo, hiring is based on merit, skill and what you bring to the role – nothing else. We’re proud to be an equal opportunity employer, and we welcome applicants from all backgrounds, communities and identities. Read our privacy notice for job applicants.

Contentful

ABOUT THE OPPORTUNITY Become part of the AI revolution at Contentful where we build real world AI solutions for thousands of active customers. At Contentful you will help imagine, drive, and build ML solutions which produce immediate customer impact by helping them get more done than they ever imagined. We are looking for an excellent  Senior Software Engineer - Machine Learning (f/m/d) who understands and has experience in this field and current Generative AI trends. If you're passionate about pushing the boundaries of what's achievable with ML products on a large scale content management system, we want you on our team. WHAT TO EXPECT?  * Measure and ensure the high-quality output of ML workloads for our enterprise customers. * Design, build, and measure production software in the Contentful Platform. * Conduct focused research and testing using tools like Jupyter Notebook. * Optimize generative AI products for accuracy, speed, and scalability. * Integrate ML cloud solutions and adapt them to our large-scale use cases. * Integrate prompt engineering and fine-tuning for customer use cases. * Develop software that scales to meet the demands of high-load customer workloads. * Lead design reviews with peers and stakeholders to decide amongst available technologies. * Drive the ML education in the team and establish a high standard of quality & ownership WHAT YOU NEED TO BE SUCCESSFUL? * Proven experience as a technical leader in a product software development environment * Proven Track Record in Model Development, including successfully developing and deploying LLM-based models for various NLP tasks in real-world applications with production workloads * Proven ability to work backwards from customer needs to deliver ML-based features that meet those needs * Ability to organize and prioritize competing workloads * Familiarity with distributed systems and cloud services (e.g., AWS, Azure, GCP) * Solid understanding of machine learning principles * Experience with container frameworks such as Docker or Kubernetes * Constructive Problem-Solving: As a natural problem-solver, you bring forward ideas that lead to practical solutions and contribute to product growth. * Up-To-Date on The Latest Updates on LLM Development & Research: From RAGs to Open-Source models over Agent Architectures – you have an inherent drive to stay up-to-date on what is the latest and greatest Preferred: * Background includes machine learning and AI implementation * You can translate a research paper into a PoC if the code does not exist WHAT’S IN IT FOR YOU? * Join an ambitious tech company reshaping the way people build digital experiences * Full-time employees receive Stock Options for the opportunity to share in the success of our company * Fertility and family building benefits, including a lifetime reimbursable wallet to support your growing family. * We value Work-Life balance and You Time! A generous amount of paid time off, including vacation days, sick days,  education days, compassion days for loss, and volunteer days * Time off to care for and focus on your growing family  * Use your personal annual education budget to improve your skills and grow in your career * Enjoy a full range of virtual and in-person events, including workshops, guest speakers, and fun team activities, supporting learning and networking exchange beyond the usual work duties  * An annual wellbeing stipend to care for your physical, financial, or emotional health * A monthly communication phone/internet stipend and phone hardware upgrade reimbursement. * New hire office equipment stipend for hybrid or distributed employees. Get the gear you need to work at your best. WHO ARE WE? Contentful is a leading digital experience platform that helps modern businesses meet the growing demand for engaging, personalized content at scale. By blending composability with native AI capabilities, Contentful enables dynamic personalization, automated content delivery, and real-time experimentation, powering next-generation digital experiences across brands, regions, and channels for more than 4,200 organizations worldwide. More than 700 people from more than 70 nations contribute their energy and creativity to Contentful, working from hubs in Berlin, Denver, San Francisco, London, New York, and distributed worldwide. EVERYONE IS WELCOME HERE! “Everyone is welcome here” is a celebrated component of our culture. At Contentful, we strive to create an inclusive environment that empowers our employees. We believe that our products and services benefit from our diverse backgrounds and experiences, and we are proud to be an equal opportunity employer. All qualified applications will receive consideration for employment without regard to race, color, national origin, religion, sexual orientation, gender, gender identity, age, physical [dis]ability, or length of time spent unemployed. We invite you to apply and join us! If you need reasonable accommodations at any point during the application or interview process, please let your recruiting coordinator know. Please be aware of scammers who may fraudulently allege to be from Contentful. These types of fraud can be carried out through copycat websites, fake email addresses claiming to be from our company, or social media. We do not ask for your personal information, such as bank account numbers, identification numbers, etc, through social media or chat-based apps, nor do we request or send money for the purchase of business equipment. If you suspect fraud, please report it to your local authorities, as well as reach out to us at security-esk@contentful.com with any information you may have. By clicking “Apply for this job,” I acknowledge that I have read the “Contentful’s Candidate Privacy Notice” and hereby consent to the collection, processing, use, and storage of my personal information as described therein.