Applied Machine Learning Scientist/Engineer — LLMs

At Sonder, we believe that every person deserves to feel safe, supported, and empowered to be at their best - wherever they are. That's why we're redefining workplace health, safety, and wellbeing through a seamless blend of technology and human expertise. Sonder's mobile platform provides 24/7, real-time support from a dedicated team of safety, medical, and mental health professionals - ensuring that our members receive immediate care when they need it most. In critical situations, we go beyond digital support, offering on-the-ground assistance to manage time-sensitive incidents.

By harnessing real-time insights, we enable organisations to take proactive steps toward a healthier, safer future, which leads directly to tangible bottom-line business outcomes.

An Exciting Time to Join Sonder

Since our founding in 2017, Sonder has experienced rapid growth, expanding operations across Australia, New Zealand, and the UK. Backed by Australia's leading venture capital firms, Seek and Blackbird, we are well-capitalised and on a mission to scale globally, partnering with corporations, educational institutions, and government agencies to transform workplace wellbeing at scale.

Our impact and scale:

• 1,000,000+ members across multiple countries
• 200+ team members, plus an extensive network of on-the-ground responders

If you're passionate about using technology and human expertise to drive meaningful change, join us in shaping the future of workplace wellbeing

Are you a recent PhD graduate or Postdoctoral researcher passionate about applying cutting-edge AI to solve real-world problems? Join Sonder as an Applied Machine Learning Scientist/Engineer — focusing on LLM Research & Fine-Tuning Engineering, and help us build a new generation of AI systems that directly impact human well-being and safety.

This is a unique opportunity for a PhD-level candidate to apply their deep academic knowledge to a mission-driven environment. This role is distinct from typical AI tooling or RAG-based roles. 

We are not seeking candidates whose primary experience is in building vector search systems or integrating off-the-shelf APIs. Instead, we require deep, hands-on expertise with the internal workings of large language models. Your work will be instrumental in developing our personalisation engine and fine-tuning state-of-the-art open-source LLMs like LLaMa, Mistral, and DeepSeek. Your research will translate directly into creating specialised LLMs that provide empathetic, life-saving support to our members. 

We're looking for someone who thrives on technical challenges and wants to see their expertise translate into a positive, tangible impact.

• Research, fine-tune, and optimise open-source LLMs using techniques such as PEFT, LoRA, and QLoRA to build our proprietary AI models.
• Contribute to the design and implementation of our personalisation and recommendation engines to deliver tailored, proactive support.
• Develop and maintain robust machine learning pipelines for model training, evaluation, and deployment.
• Collaborate closely with cross-functional teams, including product managers, software engineers, and mental health professionals, to translate research into effective product features.
• Stay current with the latest advancements in AI and LLM research, and apply new techniques to improve our systems.
• Publish and/or present research findings at conferences or in academic journals where appropriate, contributing to the broader AI community.

• A recently completed PhD or Postdoctoral experience in Machine Learning, AI, Computer Science, or a closely related quantitative field.
• Deep theoretical and practical understanding of Transformer architectures, attention mechanisms, and training dynamics.
• Hands-on experience fine-tuning open-source LLMs (e.g., LLaMa, Mistral, DeepSeek).
• Strong computer science fundamentals and coding proficiency in Python.
• Solid experience with deep learning frameworks such as PyTorch or TensorFlow.
• A profound passion for applying AI to high-impact, meaningful domains such as mental health and well-being.

Candidates with primary experience limited to building Retrieval-Augmented Generation (RAG) systems or MLOps tooling are not a suitable fit for this specific role.

• Experience with distributed training techniques for large models.
• Familiarity with cloud-based machine learning stacks (e.g., AWS, GCP).
• A track record of peer-reviewed publications in top-tier AI/ML conferences (e.g., NeurIPS, ICML, ICLR, AAAI, ACL).

Your work at Sonder will go beyond just optimising models; it will directly contribute to saving lives and improving mental well-being on a global scale. This role offers the opportunity to shape our core AI technology from the ground up while growing as a leader in a supportive, mission-driven environment. You will have the freedom to explore new research ideas and the resources to see them through to deployment, making a tangible difference in the world.

At Sonder, we thrive in a fast-paced, high-performance environment with a strong commitment to our people. Our team is a collaborative, vibrant group of passionate professionals, dedicated to making a real impact on people's lives every day.

• Hybrid and flexible working environment. Enjoy the perfect balance of in-office collaboration and work from home flexibility, empowering you to optimise your productivity and work-life balance.
• Gain free access to the Sonder app for you and your family, offering 24/7 on-demand support for health, wellbeing, and safety.
• $1000 annual contribution as part of your development plan + 2 days of study leave
• Paid parental leave with an attractive return to work policy, 12 weeks for Primary Carers and 4 weeks for Secondary Carers, plus our Primary Carers return to work at 80% for the first 3 months at full pay.
• Participate in our Employee Share Option Plan (ESOP) for you to be a part of Sonder's success. 
• Salary Packaging and novated leasing 
• ​​Access $250 annually to fund to invest in your wellbeing, empowering you to choose the support that best fits your needs.
• Free coffee on Tuesdays and catered lunch on Thursdays.
• Team social fund to connect with your team, plus monthly company wide social events. 
• Dog-friendly office. 
• Volunteer leave. 2 days per year to participate in meaningful causes and contribute back to the community.

Check out our life page for more info -

We're committed to building a diverse and inclusive workplace. We encourage applications from people of all backgrounds, experiences, abilities and identities. If you need any support with your application or the recruitment process, please reach out – we'd love to hear from you.

Due to the nature of our industry, all Sonder employees are required to complete a National Police Check and Working With Children Check.