Data Scientist (LLM)

Sorry, this job was removed at 02:22 p.m. (CST) on Thursday, Oct 30, 2025
Be an Early Applicant
Hiring Remotely in São Paulo
In-Office or Remote
Payments • Software
The Role
Who we are:

CloudWalk is a fintech company reimagining the future of financial services. We are building intelligent infrastructure powered by AI, blockchain, and thoughtful design. Our products serve millions of entrepreneurs across Brazil and the US every day, helping them grow with tools that are fast, fair, and built for how business actually works. Learn more at cloudwalk.io.

Who We’re Looking For:

We’re hiring a Data Scientist focused on Large Language Models to join our AI R&D team. You’ll work on designing, training, and optimizing LLMs that power real product features and internal tools. You’ll touch everything from architecture and data preparation to multi-scale training and evaluation.

This is not a prompt engineering or RAG-focused role. We’re looking for someone who gets the math, understands the models, and knows how to write code that scales.

You’ll work side-by-side with engineers, MLOps, and product teams to make our LLMs smarter, faster, and more useful.

What You'll Do:

  • Train and fine-tune LLMs using multi-GPU and distributed setups.
  • Analyze model performance, debug failures, and implement improvements.
  • Work with curated and synthetic datasets, including classification and generation tasks.
  • Design experiments, track results, and iterate quickly with tools like MLflow.
  • Write clean, production-ready code and collaborate via GitHub.
  • Push boundaries: think about architecture, memory efficiency, scale, and cost.

What We’re Looking For:

  • LLM understanding: You know how these models work under the hood - transformer internals, tokenization, embeddings, etc.
  • Stats and ML fundamentals: You have a solid foundation in statistics, machine learning, and optimization.
  • Coding skills: You write Python well. You’ve worked with PyTorch or JAX. You don’t fear Bash or git.
  • Training experience: You’ve trained models beyond notebooks. Bonus if you’ve worked with mixed precision, DeepSpeed, or multi-node training.
  • Systems mindset: You understand trade-offs - throughput vs memory, latency vs accuracy.
  • Good judgment: You know when to read a paper, when to read a stack trace, and when to rewrite the dataloader or part of the LLM architecture.

Bonus Points:

  • Experience with Hugging Face Transformers, Datasets, Accelerate.
  • Familiarity with Kubernetes, Ray, or custom training infra.
  • Exposure to embeddings, classification tasks, or token-level losses.
  • Ability to mentor or guide junior researchers or engineers.

How We Hire:

  • Online assessment: Online assessment: technical logic and fundamentals (Math/Calculus, Statistics, Probability, Machine Learning/Deep Learning, Code).
  • Technical interview: dive into theory and reasoning (no code).
  • Cultural interview.

  • If you are not willing to take an online quiz, do not apply.

Diversity and inclusion:
We believe in social inclusion, respect, and appreciation of all people. We promote a welcoming work environment, where each CloudWalker can be authentic, regardless of gender, ethnicity, race, religion, sexuality, mobility, disability, or education.

Similar Jobs

Airwallex Logo Airwallex

Engineering Director, GTPN Platform (Relocate to San Francisco)

Artificial Intelligence • Fintech • Payments • Business Intelligence • Financial Services • Generative AI
In-Office or Remote
11 Locations
2000 Employees
300K-325K Annually

Airwallex Logo Airwallex

Software Engineer

Artificial Intelligence • Fintech • Payments • Business Intelligence • Financial Services • Generative AI
In-Office or Remote
10 Locations
2000 Employees

Airwallex Logo Airwallex

Engineering Director, GTPN Platform (Relocate to Singapore)

Artificial Intelligence • Fintech • Payments • Business Intelligence • Financial Services • Generative AI
In-Office or Remote
13 Locations
2000 Employees
300K-325K Annually

ServiceNow Logo ServiceNow

Architect

Artificial Intelligence • Cloud • HR Tech • Information Technology • Productivity • Software • Automation
Remote or Hybrid
São Paulo, BRA
28000 Employees
Get Personalized Job Insights.
Our AI-powered fit analysis compares your resume with a job listing so you know if your skills & experience align.

The Company
São Paulo, São Paulo
501 Employees
Year Founded: 2013

What We Do

We are democratizing the payments industry in Brazil, by empowering entrepreneurs through technological, inclusive, and life-changing solutions. Based in Brazil, CloudWalk is a high-end global payment network built on modern technology and proprietary blockchain, focused in bringing a revolution to the payment ecosystem for small and medium-sized businesses. As a unicorn, the company has provided its customers with more than R$ 1 billion in savings by charging fair fees on its transactions and is now present in more than 300.000 businesses across 5.000 brazilian cities. With investors such as the Valor Capital Group, HIVE Ventures and Coatue, the company has already raised US$ 365.5 million in investments and R$3.4 billion in FDICs for anticipation of receivables in its network of financial solutions. In 2022, it was the only brazilian fintech to be featured in the "The Retail Tech 100" ranking by CB Insights, on the "Protection Solutions for Payments and Frauds".

Similar Companies Hiring

Rain Thumbnail
Web3 • Payments • Infrastructure as a Service (IaaS) • Fintech • Financial Services • Cryptocurrency • Blockchain
New York, NY
70 Employees
Scotch Thumbnail
Software • Retail • Payments • Fintech • eCommerce • Artificial Intelligence • Analytics
US
25 Employees
Milestone Systems Thumbnail
Software • Security • Other • Big Data Analytics • Artificial Intelligence • Analytics
Lake Oswego, OR
1500 Employees

Sign up now Access later

Create Free Account

Please log in or sign up to report this job.

Create Free Account