Founding AI Engineer

Bjak
Brussels, Belgium
2 days ago

Role details

Contract type
Permanent contract
Employment type
Full-time (> 32 hours)
Working hours
Regular working hours
Languages
English

Job location

Brussels, Belgium

Tech stack

Training Data
Artificial Intelligence
Apache HTTP Server
Data Systems
Open Source Technology
TensorFlow
Scientific Computating
Software Engineering
Data Processing
PyTorch
Large Language Models
Multi-Agent Systems
Spark
Deep Learning
Data Strategy

Job description

Transform language models into real-world, high-impact product experiences.

A1 is a self-funded AI group, operating in full stealth. We're building a new global consumer AI application focused on an important but underexplored use case.

You will shape the core technical direction of A1 - model selection, training strategy, infrastructure, and long-term architecture. This is a founding technical role: your decisions will define our model stack, our data strategy, and our product capabilities for years ahead.

You won't just fine-tune models - you'll design systems: training pipelines, evaluation frameworks, inference stacks, and scalable deployment architectures. You will have full autonomy to experiment with frontier models (LLaMA, Mistral, Qwen, Claude-compatible architectures) and build new approaches where existing ones fall short.

Why This Role Matters

You are creating the intelligence layer of A1's first product, defining how it understands, reasons, and interacts with users.

Your decisions shape our entire technical foundation - model architectures, training pipelines, inference systems, and long-term scalability.

You will push beyond typical chatbot use cases, working on a problem space that requires original thinking, experimentation, and contrarian insight.

You influence not just how the product works, but what it becomes, helping steer the direction of our earliest use cases.

You are joining as a founding builder, setting engineering standards, contributing to culture, and helping create one of the most meaningful AI applications of this wave.

What You'll Do

Build end-to-end training pipelines: data * training * eval * inference

Design new model architectures or adapt open-source frontier models

Fine-tune models using state-of-the-art methods (LoRA/QLoRA, SFT, DPO, distillation)

Architect scalable inference systems using vLLM / TensorRT-LLM / DeepSpeed

Build data systems for high-quality synthetic and real-world training data

Develop alignment, safety, and guardrail strategies

Design evaluation frameworks across performance, robustness, safety, and bias

Own deployment: GPU optimization, latency reduction, scaling policies

Shape early product direction, experiment with new use cases, and build AI-powered experiences from zero

Explore frontier techniques: retrieval-augmented training, mixture-of-experts, distillation, multi-agent orchestration, multimodal models

What It's Like to Work Here

You take ownership - you solve problems end-to-end rather than wait for perfect instructions

You learn through action - prototype * test * iterate * ship

You're calm in ambiguity - zero-to-one building energises you

You bias toward speed with discipline - V1 now > perfect later

You see failures and feedback as essential to growth

You work with humility, curiosity, and a founder's mindset

You lift the bar for yourself and your teammates every day

Requirements

Strong background in deep learning and transformer architectures

Hands-on experience training or fine-tuning large models (LLMs or vision models)

Proficiency with PyTorch, JAX, or TensorFlow

Experience with distributed training frameworks (DeepSpeed, FSDP, Megatron, ZeRO, Ray)

Strong software engineering skills - writing robust, production-grade systems

Experience with GPU optimization: memory efficiency, quantization, mixed precision

Comfortable owning ambiguous, zero-to-one technical problems end-to-end

Nice to Have

Experience with LLM inference frameworks (vLLM, TensorRT-LLM, FasterTransformer)

Contributions to open-source ML libraries

Background in scientific computing, compilers, or GPU kernels

Experience with RLHF pipelines (PPO, DPO, ORPO)

Experience training or deploying multimodal or diffusion models

Experience in large-scale data processing (Apache Arrow, Spark, Ray)

Prior work in a research lab (Google Brain, DeepMind, FAIR, Anthropic, OpenAI)

What You'll Get

Extreme ownership and autonomy from day one - you define and build key model systems.

Founding-level influence over technical direction, model architecture, and product strategy.

Remote-first flexibility

High-impact scope-your work becomes core infrastructure of a global consumer AI product.

Competitive compensation and performance-based bonuses

Backing of a profitable US$2B group, with the speed of a startup

Insurance coverage, flexible time off, and global travel insurance

Opportunity to shape a new global AI product from zero

A small, senior, high-performance team where you collaborate directly with founders and influence every major decision.

Our Team & Culture

We operate as a dense, senior, high-performance team. We value clarity, speed, craftsmanship, and relentless ownership. We behave like founders - we build, ship, iterate, and hold ourselves to a high technical bar.

If you value excellence, enjoy building real systems, and want to be part of a small team creating something globally impactful, you'll thrive here.

About A1

A1 is a self-funded, independent AI group backed by BJAK, focused on building a new consumer AI product with global impact. We're assembling a small, elite team of ML and engineering builders who want to work on meaningful, high-impact

Requirements

Strong background in deep learning and transformer architectures

Hands-on experience training or fine-tuning large models (LLMs or vision models)

Proficiency with PyTorch, JAX, or TensorFlow

Experience with distributed training frameworks (DeepSpeed, FSDP, Megatron, ZeRO, Ray)

Strong software engineering skills - writing robust, production-grade systems

Experience with GPU optimization: memory efficiency, quantization, mixed precision

Comfortable owning ambiguous, zero-to-one technical problems end-to-end

Nice to Have

Experience with LLM inference frameworks (vLLM, TensorRT-LLM, FasterTransformer)

Contributions to open-source ML libraries

Background in scientific computing, compilers, or GPU kernels

Experience with RLHF pipelines (PPO, DPO, ORPO)

Experience training or deploying multimodal or diffusion models

Experience in large-scale data processing (Apache Arrow, Spark, Ray)

Prior work in a research lab (Google Brain, DeepMind, FAIR, Anthropic, OpenAI)

What You'll Get

Extreme ownership and autonomy from day one - you define and build key model systems.

Founding-level influence over technical direction, model architecture, and product strategy.

Benefits & conditions

High-impact scope-your work becomes core infrastructure of a global consumer AI product.

Competitive compensation and performance-based bonuses

Backing of a profitable US$2B group, with the speed of a startup

Insurance coverage, flexible time off, and global travel insurance

Opportunity to shape a new global AI product from zero

A small, senior, high-performance team where you collaborate directly with founders and influence every major decision.

Our Team & Culture

We operate as a dense, senior, high-performance team. We value clarity, speed, craftsmanship, and relentless ownership. We behave like founders - we build, ship, iterate, and hold ourselves to a high technical bar.

If you value excellence, enjoy building real systems, and want to be part of a small team creating something globally impactful, you'll thrive here.

About A1

A1 is a self-funded, independent AI group backed by BJAK, focused on building a new consumer AI product with global impact. We're assembling a small, elite team of ML and engineering builders who want to work on meaningful, high-impact

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