Senior Principal Data Scientist - RL & LLM for Marketplace

GrabTaxi Holdings Pte. Ltd.; Singapore; On-site; SGD 300,000 - 540,000; Full time

Benefits offered by this job

Term Life Insurance

Medical Insurance

GrabFlex benefits

Parental leave

Birthday leave

Love-all-Serve-all volunteering leave

Grabber Assistance Programme

FlexWork hours

Job summary

Grab is seeking a Senior Principal Data Scientist to lead automated marketplace optimization. You will drive RL-based pricing, dispatch, and supply decisions, and architect LLM-powered behavioural intelligence at scale.

You will oversee a small team, report to Head of Data Science, and work from Grab's One-North Singapore office, shaping research and production directions across reinforcement learning and language models.

Qualifications

• PhD in Computer Science, Operations Research, Applied Mathematics, or related field with 10+ years experience.
• Strong foundation in RL, MDPs and reward design.
• Experience building production ML/RL systems with online learning or simulation-based optimization.
• Knowledge of world models and sequential modelling (RNNs, transformers).
• Hands-on experience fine-tuning large language models in production with PF methods (LoRA/QLoRA/PEFT).
• Ability to design evaluation frameworks for generative models and ensure safe deployment.

Responsibilities

• Design end-to-end RL systems that optimize pricing, dispatch, and supply repositioning.
• Develop latent world models and marketplace state representations.
• Optimize multiple levers across pricing, dispatch, and supply repositioning.
• Create policy evaluation frameworks and monitoring for production deployment.
• Fine-tune open-source LLMs on domain data for prediction, reasoning, and simulation.
• Design training strategies for language models (supervised fine-tuning, alignment).
• Collaborate with data and backend engineers to deploy RL/LLM in real-time production.

Skills

RL fundamentals

Production ML systems

World models / sequential modelling

Fine-tuning LLMs in production

Evaluation frameworks for generative

Distributed training frameworks

Python / ML frameworks (PyTorch or TF)

Spark / Ray for scalable computing

Education

PhD in Computer Science or related field

Tools

PyTorch

TensorFlow

DeepSpeed

Spark

Ray

Job description

Grab is seeking a Senior Principal Data Scientist to lead automated marketplace optimization. You will drive RL-based pricing, dispatch, and supply decisions, and architect LLM-powered behavioural intelligence at scale.

You will oversee a small team, report to Head of Data Science, and work from Grab's One-North Singapore office, shaping research and production directions across reinforcement learning and language models.