Senior Machine Learning Engineer

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.

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. As an ML Researcher, you will be responsible for its development. 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: * Designing and implementing models, most often of deep neural networks, used to predict the behavior and preferences of Internet users * Analysis of the latest works in the field of Machine Learning * Conducting and analyzing A/B tests of new solutions * Developing and testing new approaches to modeling key issues, such as bidding in first-price auctions Desired Experience: * 4+ years of hands-on experience with Machine Learning / Data Science  * Interest and willingness to constantly develop in the area of Machine Learning * Knowledge of statistics and probability * Proficiency in programming * C1 level in Polish Selected technologies used: * Python, Java, Scala * PyTorch, NumPy, Pandas * Jupyter Notebooks Additional advantages will be: * Experience in the ML industry * Experience in designing recommendation systems * Practical knowledge of the tools we use Sample topics: * Implementation and analysis of new model architectures, such as convolutional networks, transformer * Analyze the difference in the distribution of training and production data. Estimating the scale of the problem, identifying the best solution, analysis, implementation, deployment * Experiments with the use of transfer learning * A completely new approach to generating product recommendations that is free from proxy targets and uses contrastive loss function We Offer:   * Cooperate in a team of enthusiasts with experience in machine learning who willingly share their knowledge and skills * Extremely flexible cooperation conditions - you cooperate when it is convenient for you and devote as much time as you can; you can cooperate fully remotely * Access to the latest technologies and the possibility of real use of them in a large-scale and highly dynamic project; * Possibility of using the possessed knowledge and competences in practical applications - while optimizing algorithms supporting hundreds of millions of Internet users and monthly buyers of billions of advertising views in the RTB model, based on extensive data sets * The effects of your cooperate immediately visible in the company's business results * Possibility to publish 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. 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.

Hybrus AB

We are looking for a Senior ML Engineer for our client in Stockholm for a long term assignment. Employment type: Fixed Term Contract Duration : 6 Months - 1 Year Location : Stockholm Work type : Onsite ( potential hybrid options) As a Senior ML Engineer, you will be working hands-on to optimise training and deployment of ML models to be quick and cost-efficient. You will also be at the forefront of putting our ML models on mobile devices to enhance data privacy and customer experience. To achieve this, you will need to collaborate with teams to establish best practices and tools for efficient ML model development and deployment, particularly on mobile platforms. You will be expected to help Client reach and stay at the cutting edge of ML training and deployment, as well as explore new frontiers such as federated learning. The impact you will create: ● Lead the technical evaluation and implementation of Federated Learning (FL) initiatives . ● Work closely with Data Science, Android, and Backend teams to design and validate end-to-end FL workflows. ● Define and execute experimentation plans to assess the effectiveness of FL for use cases. ● Develop and optimize language models and on-device training pipelines for privacy-preserving machine learning. ● Establish model evaluation frameworks, success metrics, and validation strategies for FL-based systems. ● Identify technical risks, assumptions, and limitations, and provide recommendations on architecture and future direction. ● Help shape the roadmap for scaling FL from experimentation to production-ready systems What you bring in: ● 5+ years of experience in Machine Learning Engineering, Applied Machine Learning, or related fields. ● Hands-on experience with Federated Learning frameworks such as TensorFlow Federated, Flower, FedML, OpenFL, or equivalent. ● Strong understanding of distributed machine learning, model training, and model evaluation techniques. ● Experience working with NLP, language models, embeddings, or text classification systems. ● Hands-on experience deploying ML models on mobile devices (e.g., TensorFlow Lite, Core ML, ONNX Runtime Mobile). ● Strong knowledge of machine learning frameworks such as TensorFlow and PyTorch. ● Experience designing and executing ML experiments, analyzing results, and driving data-driven decisions. ● Familiarity with privacy-preserving machine learning concepts and challenges. ● Ability to work across multiple teams and communicate complex technical concepts to both technical and non-technical stakeholders. ● Strong problem-solving skills and ability to operate in an exploratory research and PoC environment. It would be great if you also have: ● Experience deploying or operating Federated Learning systems in production environments. ● Hands-on experience with on-device machine learning technologies such as TensorFlow Lite, ONNX Runtime Mobile, or Core ML. ● Experience building machine learning solutions for mobile applications. ● Experience in messaging, spam detection, fraud detection, trust & safety, or similar domains. ● Familiarity with the challenges of running ML workloads on mobile devices. ● Experience with MLOps, model monitoring, and automated training/deployment pipelines. Please let us know if you are interested and if yes, then apply to careers@hybrus.se with your CV, including details about Salary, Notice period and Visa Status.