Algorithm Expert - Financial Foundation LLM

About the Company

DiDi Global Inc. is the world’s leading mobility technology platform. It offers a wide range of app-based services across markets including Asia-Pacific, Latin America and Africa, including ride hailing, taxi hailing, chauffeur, hitch and other forms of shared mobility as well as auto solutions, food delivery, intra-city freight, and financial services. DiDi provides car owners, drivers, and delivery partners with flexible work and income opportunities. It is committed to collaborating with policymakers, the taxi industry, the automobile industry and communities to solve transportation, environmental, and employment challenges through AI technology and localized smart transportation innovations. DiDi strives to create better life experiences and greater social value by building a safe, inclusive, and sustainable transportation and local services ecosystem for cities of the future.

About the Role

In this role, you will focus on the following key areas:

• Foundation Model Pre-training: Design and implement the pre-training pipeline for financial behavior sequence foundation models, including pre-training objective selection (CLM/MLM/Hybrid), tokenization architecture experimentation (Flat/3D-Transformer/KVT), and scaling experiments.
• Multi-source Sequence Modeling: Build a unified sequence representation for behavioral data across multiple domains (payments, ride-hailing, food delivery, credit); design and validate the impact of data-source mixing ratios on model performance.
• Multi-entity and Multi-scale Fusion: Design an Account-Card dual-dimension sequence modeling scheme, along with a cross-temporal-scale fusion architecture bridging micro-level behaviors (millisecond-granularity event tracking) and macro-level behaviors (day/week-level transactions).
• Ablation Studies and Evaluation Framework: Build a systematic ablation experiment framework; design a freeze-backbone + linear head evaluation pipeline to drive architecture decisions.
• Production Deployment: Integrate pre-trained representations into downstream risk-control scenarios (stolen-card detection, credit scoring, etc.); design a Blending Module and complete SFT fine-tuning and online deployment.

Requirements

Must Have:

• Master's degree or above in Computer Science, Mathematics, Statistics, or a related field.
• 3+ years of deep learning algorithm R&D experience, with hands-on experience building a pre-trained model from scratch and completing the full training pipeline.
• Proficiency in Transformer architectures and variants (GPT/BERT/FT-Transformer/MoE), with practical sequence modeling experience.
• Familiar with at least one mainstream deep learning framework (PyTorch preferred); experience with distributed training (multi-GPU / multi-node).
• Solid experimental design skills: ability to independently conduct ablation studies and scaling-law experiments and draw reliable conclusions.
• Strong engineering implementation skills; able to iterate efficiently on model code and training pipelines.

Nice to Have:

• Modeling experience in financial risk control / anti-fraud / credit scoring.
• Publications on Foundation Models / Self-Supervised Learning (NeurIPS/ICML/ICLR/KDD/WWW, etc.).
• Familiarity with Contrastive Learning, ELECTRA, cross-modal fusion, and related techniques.
• Experience with time-series / event-sequence modeling (e.g., TimeMixer, TrajGPT).
• Experience with graph neural networks or graph-based anomaly detection.

Benefits

At DiDi, we foster a culture that values:

• User Value: We strive to always create valuable experiences for our users in everything we do, focusing on innovation that ensures safety, pleasantness, and efficiency.
• Data-Driven Decisions: We make informed decisions by analyzing valuable metrics to navigate the business landscape strategically.
• Win-Win Collaboration: Success is a team sport. We communicate with candor and execute with excellence, ensuring everyone's best interests are at heart.
• Integrity: Integrity is at the core of our business. We aim to do the right thing, speak our minds, and listen to each other.
• Growth: We always strive to do better by venturing beyond our comfort zones, learning from mistakes, and helping each other grow.
• Diversity and Inclusion: Diversity is one of our biggest strengths. We respect each other and believe in equal opportunities for all, committed to building inclusive and diverse teams.

DiDi is an Equal Opportunity Employer. Employment and advancement decisions are based on the needs of the position and the qualifications of the candidate. We do not discriminate against any employee or applicant based on gender, age, sexual orientation, nationality, marital status, pregnancy/maternity, disability, race, religion, beliefs, or any other status protected by applicable laws.