Senior Machine Learning Researcher

RTB House

Location: Poland   We Are: RTB House is a global company that provides state-of-the-art marketing technologies for top brands and agencies worldwide. Its proprietary ad-buying engine is the first in the world to be powered entirely by Deep Learning algorithms, enabling advertisers to generate outstanding results and reach their goals at every stage of the funnel. Founded in 2012, and now operating in 90+ markets, RTB House has always been private-by-design. It embraces first-party advertising and a relentless approach to innovation. RTB House offers end-to-end Deep Learning-powered AdTech products and solutions to maximize conversion, drive new customer acquisition, create engagement, and fuel long-term demand for a global base of clients. Desired Experience: * Expertise in designing and implementing complex IT systems. * Ability to develop user-friendly, versatile tools. * Proficiency in at least one programming language, such as Python, C++, Java, or Scala, along with expertise in Linux. * Strong skills in evaluating and optimizing system performance, from initial design through to production troubleshooting. * Deep understanding of algorithms and data structures. * Initiative and creativity to improve existing solutions. * Ability to work effectively both within and across teams. * C1 level in Polish Additional Advantages: * Previous experience in the field of Machine Learning is not required, but would be an asset. * Solid foundation in mathematics. * Experience with GPU programming and Machine Learning frameworks such as Torch, PyTorch, or TensorFlow. * Proven experience with distributed systems. * Familiarity with Big Data technologies such as Hadoop, Kafka, Storm, Spark, or Flink. * Hands-on experience with Google Cloud Platform (GCP) or similar cloud providers. We Offer: * The opportunity to cooperate with a team of enthusiasts experienced in Machine Learning, Big Data, and distributed systems, who are eager to share their knowledge and skills. * Flexible cooperate hours, with the possibility of remote cooperate or cooperate from our office in Warsaw. * Access to the latest technologies, with the opportunity to apply them in a large-scale and fast-paced project. * An opportunity to apply your expertise in optimizing algorithms that support hundreds of millions of internet users and billions of ad views per month within the RTB model. * The ability to see the immediate impact of your cooperate on the company's business outcomes. * The possibility of publishing your results. * Cooperation based on B2B contract or Contract of Mandate * You can cooperate 100 % remotely or choose one of our office spaces in Warsaw or Cracow. Daily Responsibilities: * Developing and maintaining the ML training platform and the bidding infrastructure that evaluates ML models in the production environment. * Identifying performance bottlenecks and optimizing critical, low-level parts of the system. * Ensuring the reliability and scalability of implementations, and creating performance and correctness tests for new system components. * Testing and benchmarking open-source Big Data and ML technologies to assess their suitability for the production environment.   Apply now! You don't need to tick every box to apply. If you are passionate about digital marketing, send us your CV, and we'll review it.

RTB House

Location: Poland   We Are: RTB House is a global company that provides state-of-the-art marketing technologies for top brands and agencies worldwide. Its proprietary ad-buying engine is the first in the world to be powered entirely by Deep Learning algorithms, enabling advertisers to generate outstanding results and reach their goals at every stage of the funnel. Founded in 2012, and now operating in 90+ markets, RTB House has always been private-by-design. It embraces first-party advertising and a relentless approach to innovation. RTB House offers end-to-end Deep Learning-powered AdTech products and solutions to maximize conversion, drive new customer acquisition, create engagement, and fuel long-term demand for a global base of clients.   You Will:  We're looking for a Senior Software Engineer to help us design, build, and optimize high-performance backend systems that power real-time bidding (RTB) and machine learning at internet scale. You’ll cooperate on software that handles billions of daily transactions with strict latency and reliability constraints - all in a distributed, low-latency environment.   Desired Experience:  * Expertise in designing and implementing complex IT systems. * Ability to develop user-friendly, versatile tools. * Proficiency in at least one programming language, such as Python, C++, Java, or Scala, along with expertise in Linux. * Strong skills in evaluating and optimizing system performance, from initial design through to production troubleshooting. * Deep understanding of algorithms and data structures. * Initiative and creativity to improve existing solutions. * Ability to cooperate effectively both within and across teams. * C1 level in Polish   Additional Advantages: * Previous experience in the field of Machine Learning is not required, but would be an asset. * Solid foundation in mathematics. * Experience with GPU programming and Machine Learning frameworks such as Torch, PyTorch, or TensorFlow. * Proven experience with distributed systems. * Familiarity with Big Data technologies such as Hadoop, Kafka, Storm, Spark, or Flink. * Hands-on experience with Google Cloud Platform (GCP) or similar cloud providers.   In Return, We Offer: * A highly competitive salary. * The opportunity to cooperate with a team of enthusiasts experienced in Machine Learning, Big Data, and distributed systems, who are eager to share their knowledge and skills. * You can cooperate 100 % remotely or choose one of our office spaces in Warsaw or Cracow. * Access to the latest technologies, with the opportunity to apply them in a large-scale and fast-paced project. * An opportunity to apply your expertise in optimizing algorithms that support hundreds of millions of internet users and billions of ad views per month within the RTB model. * The ability to see the immediate impact of your cooperate on the company's business outcomes. * The possibility of publishing your results. * Cooperation based on B2B contract.   Daily Responsibilities: * Developing and maintaining the ML training platform and the bidding infrastructure that evaluates ML models in the production environment. * Identifying performance bottlenecks and optimizing critical, low-level parts of the system. * Ensuring the reliability and scalability of implementations, and creating performance and correctness tests for new system components. * Testing and benchmarking open-source Big Data and ML technologies to assess their suitability for the production environment.     Apply now! You don't need to tick every box to apply. If you are passionate about digital marketing, send us your CV, and we'll review it.

Monzo

🚀 We’re on a mission to make money work for everyone. We’re waving goodbye to the complicated and confusing ways of traditional banking. After starting as a prepaid card, our product offering has grown a lot in the last 10 years in the UK. As well as personal and business bank accounts, we offer joint accounts, accounts for 16-17 year olds, a free kids account and credit cards in the UK, with more exciting things to come beyond. Our UK customers can also save, invest and combine their pensions with us.  With our hot coral cards and get-paid-early feature, combined with financial education on social media and our award winning customer service, we have a long history of creating magical moments for our customers! We’re not about selling products - we want to solve problems and change lives through Monzo ❤️ ----------------------------------------------------------------------------------------------------------------------------------   📍London/Cardiff/UK Remote | 💰£113,200 - £145,200 + equity + Incentive Awards tied to your performance + Benefits  ✨ Our Operations Machine Learning team ⭐ We’re building the machine learning and optimisation systems that help Monzo provide fast, efficient and resilient customer support at scale. You’ll lead Machine Learning for our Workforce Management vertical: the organisation that makes sure Monzo has the right human support supply to meet customer demand. The team works on demand forecasting, real-time supply <> demand matching, problem routing and escalation, and predictive models that help us understand how long work will take, what might become late, and where the next best human support should be assigned. This is a great role for someone who is still close to technical work. You might be a Tech Lead, Team Lead, Senior Machine Learning Scientist or Senior Machine Learning Engineer who has recently been building models and systems yourself, and is excited to grow into a broader leadership role. Not everything here is about LLMs. You’ll work on rigorous ML, forecasting, optimisation and operations research problems where quantitative thinking, pragmatic delivery and strong product judgement really matter. You’ll lead a growing team of Machine Learning Scientists, embedded in product squads working alongside data scientists, backend, mobile and web engineers, product managers, user researchers, designers and operations specialists. 🔑You’ll play a key role by… * Shaping the ML strategy for Workforce Management, helping us decide where ML, forecasting and optimisation can have the biggest impact for customers and human agents. * Leading the design, build and delivery of production ML systems across forecasting, routing, assignment, escalation and time-to-completion prediction. * Staying close to the technical details: helping the team frame problems well, choose the right modelling approach, define robust validation, review trade-offs and ship safely. * Working with Product, Engineering, Data and Operations leaders to turn ambiguous operational problems into pragmatic, iterative ML systems that improve real customer outcomes. * Coaching and developing Machine Learning Scientists through regular 1:1s, feedback and technical guidance. * Creating healthy ways of working for the team: clear priorities, strong technical standards, good documentation, sensible monitoring, and space for people to do their best work. * Contributing to the wider Machine Learning discipline at Monzo, helping us scale how we build, ship and operate ML systems in production. 🤩 We’d love to hear from you if… * You’ve recently worked as a hands-on Machine Learning practitioner, for example as a Senior IC, Tech Lead, Team Lead or ML manager. * You have strong foundations in ML, statistics, forecasting, optimisation or operations research, and enjoy applying them to messy real-world problems. * You’ve built, shipped or owned ML systems in production, and understand what it takes to make models useful, reliable, monitored and safe. * You can move between technical detail and business context, explaining complex ML ideas clearly to technical and non-technical people. * Coaching others is something you enjoy and take seriously. You may already have people management experience, but we’re also open to people taking their first formal step into management. * Ambiguous problem spaces energise you. The right answer might involve a model, an algorithm, a product change, an operational process, or a combination of all four. * Customer outcomes matter to you, and you want to build systems that help people get answers to their problems quickly and efficiently. * You’re adaptable, curious and excited by quantitative problems. Not ticking every box? That’s totally okay! Studies show that women and people of colour might hesitate to apply unless they meet every single requirement. At Monzo, we’re dedicated to creating a diverse and welcoming team. If you’re passionate about this role and keen to learn and grow with us, we encourage you to apply— even if you don’t have everything that's listed just yet. Drop us your application, we’d love to hear from you! 🙌 What’s in it for you 💰 £113,200 - £145,200 ➕Incentive Awards tied to your performance. ✈️ We’ll help you relocate to the UK. ✅ We can sponsor your visa.  📍This role can be based in our London office, but we're open to distributed working within the UK (with ad hoc meetings in London)  ⏰ We offer flexible working hours and trust you to work enough hours to do your job well, and at times that suit you and your team.  📚 £1,000 learning budget each year to use on books, training courses and conferences. 🏡 We will set you up to work from home; all employees are given Macbooks and for fully remote workers we will provide extra support for your work-from-home setup.  ➕ Plus lots more! Read our full list of benefits. 🌈 The application journey has 3 key steps * Recruiter Call * Initial Call * Full Loop: ML Modelling Skills Interview, Product & ML interview, Project Deep Dive Interview, Leadership interview This process should take around 3-4 weeks - your schedule is really important to us, so we promise to be as flexible as possible!  We have some guidelines on using Artificial Intelligence (AI) to ace an application and interview at Monzo. You can read them here. #LI-REMOTE ---------------------------------------------------------------------------------------------------------------------------------- Equal opportunities for everyone Diversity and inclusion are a priority for us and we’re making sure we have lots of support for all of our people to grow at Monzo. At Monzo, we’re embracing diversity by fostering an inclusive environment for all people to do the best work of their lives with us. This is integral to our mission of making money work for everyone. You can read more in our blog, 2026 Diversity and Inclusion Report and 2025 Gender Pay Gap Report. We’re an equal opportunity employer. All applicants will be considered for employment without attention to age, ethnicity, religion, sex, sexual orientation, gender identity, family or parental status, national origin, or veteran, neurodiversity or disability status. If you have a preferred name, please use it to apply. We don't need full or birth names at application stage 😊