AI/ML Developer at Payoneer

About Payoneer Founded in 2005, Payoneer is the global financial platform that removes friction from doing business across borders, with a mission to connect the world’s underserved businesses to a rising global economy. We’re a community with over 2,500 colleagues all over the world, working to serve customers, and partners in over 190 countries and territories. By taking the complexity out of the financial workflows–including everything from global payments and compliance to multi-currency and workforce management, to providing working capital and business intelligence–we give businesses the tools they need to work efficiently worldwide and grow with confidence. Role Summary We are looking for a technically strong AI / ML Developer with hands-on expertise in training and fine-tuning Small Language Models (SLMs) and RAG Solutions. The ideal candidate will drive end-to-end AI Solutions — from dataset curation and pre-processing to training, evaluation, and production deployment. You will collaborate closely with product, product engineers, and infrastructure teams to build AI solutions that are efficient, scalable, and business-aligned. Key Responsibilities 1 Model Design & Training • Design, train, and fine-tune Small Language Models (SLMs) using frameworks such as PyTorch, TensorFlow, or JAX. • Conduct experiments with supervised fine-tuning (SFT), reinforcement learning from human feedback (RLHF), and instruction tuning. • Implement efficient training pipelines leveraging distributed training (DDP, FSDP) across GPU/TPU clusters. • Perform hyperparameter optimisation, ablation studies, and model selection based on benchmark results. • Develop and maintain data pipelines for collecting, cleaning, tokenising, and pre-processing large-scale training corpora. 2 Model Evaluation & Quality • Define and implement evaluation frameworks including perplexity, BLEU, ROUGE, BERTScore, and task-specific benchmarks. • Conduct red-teaming, bias analysis, and safety evaluations to ensure responsible AI deployment. • Benchmark models against established baselines (e.g., GPT-2, Phi, Mistral) and track performance over iterations. • Collaborate with QA teams to build regression suites for model versioning and continuous evaluation. 3 MLOps & Deployment • Containerise and deploy models using Docker, Kubernetes, and cloud-native ML platforms (AWS SageMaker / GCP Vertex AI / Azure ML). • Build and maintain model registries, experiment tracking (MLflow, Comet), and reproducible training pipelines. • Optimise inference performance through quantisation (INT8, INT4), pruning, distillation, and ONNX/TensorRT conversion. • Monitor model drift, data drift, and performance degradation in production; implement automated retraining triggers. 4 Research & Innovation • Stay current with state-of-the-art NLP/LLM research; prototype and validate new techniques from published literature. • Contribute to internal knowledge sharing, technical documentation, and model cards. • Explore parameter-efficient fine-tuning (PEFT) methods such as LoRA, QLoRA, and Adapter layers. • Investigate and apply mixture-of-experts (MoE), retrieval-augmented generation (RAG), and agentic workflows as needed. 5 Collaboration & Stakeholder Management • Work with product managers and domain experts to translate business requirements into model objectives and KPIs. • Communicate model capabilities, limitations, and trade-offs clearly to both technical and non-technical stakeholders. • Participate in architecture reviews, sprint planning, and cross-functional design discussions. Required Qualifications 1 Education • Bachelor's or Master's degree in Computer Science, Data Science, Machine Learning, Statistics, or a related quantitative field. • Equivalent professional experience with a strong portfolio of delivered AI/ML projects will be considered. 2 Experience • 4 – 6 years of professional experience in machine learning or NLP engineering. • Minimum 2 years of direct, hands-on experience in training or fine-tuning language models (LLMs or SLMs). • Demonstrable experience taking a model from dataset preparation through to production deployment. 3 Technical Skills — Core • Programming: Python (proficient); familiarity with C++/CUDA a plus. • Deep Learning Frameworks: PyTorch (primary), TensorFlow or JAX. • NLP Libraries: Hugging Face Transformers, Datasets, PEFT, TRL, Accelerate. • Training Infrastructure: Multi-GPU training, FSDP, DeepSpeed ZeRO stages 1–3. • Data Engineering: Pandas, NumPy, Apache Spark or Dask for large-scale data prep. • Vector DBs & Retrieval: FAISS, Pinecone, Weaviate, or equivalent. • Cloud Platforms: AWS, GCP, or Azure — ML-specific services (SageMaker, Vertex AI, etc.). • Version Control & CI/CD: Git, GitHub/GitLab, MLflow or W&B for experiment tracking. 4 Technical Skills — Nice to Have • Experience with multimodal models or vision-language models (VLMs). • Knowledge of model safety, alignment techniques, and responsible AI frameworks. • Familiarity with LangChain, LlamaIndex, or similar orchestration frameworks. • Contributions to open-source ML projects or publications at NeurIPS, ICML, EMNLP, ACL. Behavioural Competencies • Intellectual Curiosity: Keeps up with rapidly evolving AI research and applies learnings pragmatically. • Problem Solving: Approaches ambiguous problems with structured, data-driven thinking. • Ownership: Takes full accountability for model quality, timelines, and production reliability. • Collaboration: Works effectively in cross-functional teams with diverse skill sets. • Communication: Distils complex technical concepts for diverse audiences. • Adaptability: Thrives in a fast-paced environment where priorities evolve with research breakthroughs. The Payoneer Ways of Working Act as our customer’s partner on the inside Learning what they need and creating what will help them go further. Do it. Own it. Being fearlessly accountable in everything we do. Continuously improve Always striving for a higher standard than our last. Build each other up Helping each other grow, as professionals and people. If this sounds like a business, a community, and a mission you want to be part of, apply today. We are committed to providing a diverse and inclusive workplace. Payoneer is an equal opportunity employer, and all qualified applicants will receive consideration for employment no matter your race, color, ancestry, religion, sex, sexual orientation, gender identity, national origin, age, disability status, protected veteran status, or any other characteristic protected by law. If you require reasonable accommodation at any stage of the hiring process, please speak to the recruiter managing the role for any adjustments. Decisions about requests for reasonable accommodation are made on a case-by-case basis.