Senior ML Research Engineers

Location: Brazil — Remote

Employment Type: Full-time

Compensation: €100,000–€110,000/year

Relocation: London relocation available — compensation negotiable

Visa Sponsorship: Available

FitNext Exclusive:

Company Overview

We’re working with a VC-backed AI/ML startup developing a novel foundation model focused on automated software delivery for embedded control systems.

The company is looking for a Senior ML Engineer to join its early-stage team and take significant ownership of the research, development, optimization, and production deployment of its AI technology.

You’ll work directly with the founding team in a highly hands-on environment, helping shape both the model and the infrastructure behind it.



The Challenge

As a Senior ML Engineer, you’ll work across the full lifecycle of advanced AI/ML systems — from model architecture and large-scale training to optimization, inference, deployment, and evaluation.

You will be expected to work deeply with the models themselves while also building the infrastructure required to train and operate them at scale.

Your responsibilities will include:

• Designing and implementing large-scale AI/ML and foundation models
• Developing and optimizing model architectures and training pipelines
• Working on large-scale distributed training and inference
• Writing and optimizing custom CUDA kernels
• Improving model performance, efficiency, and reliability
• Building and operating ML infrastructure in the cloud
• Developing production-ready model deployment and serving systems
• Building evaluation, monitoring, and benchmarking systems
• Debugging complex ML workloads and performance bottlenecks
• Working closely with the founding team to solve technically challenging problems

Must Have

• Strong hands-on experience building and deploying AI/ML systems
• Deep hands-on experience designing and implementing large-scale foundation models
• Strong CUDA C/C++ experience, including custom CUDA kernels
• Experience with modern model architectures such as MoE (Mixture of Experts) or state-space models
• Experience with distributed / large-scale training and inference
• Strong Python skills
• Strong experience with PyTorch or another major deep learning framework
• Experience optimizing and debugging deep learning models
• Experience building and operating ML systems on AWS, Azure, or GCP
• Strong experience with ML infrastructure, deployment, monitoring, and evaluation
• Strong understanding of modern AI/ML systems and model development
• Experience working in ambiguous, fast-paced environments
• Ability to take significant ownership and operate independently in an early-stage startup environment

Nice to Have

• Experience with large-scale training datasets and data curation
• Experience with distributed training across specialized hardware
• Experience with efficient model serving frameworks
• Experience building internal ML tooling, benchmarks, and evaluation systems
• Previous experience at an early-stage AI/ML startup
• Experience taking AI/ML research from experimentation into production

Relocation

The role is open to candidates based in Brazil and working remotely.

Candidates interested in relocating to London are also welcome.

For candidates relocating to the UK:

• Compensation is negotiable
• Visa sponsorship is available

Process

1. FitNext screening
2. Technical interview
3. ML / AI technical deep dive
4. Technical interview with the team
5. Final interview with the founding team
6. Offer