Junior Machine Learning Engineer

Multiverse Computing LLC; Barcelona; Hybrid; EUR 40,000 - 70,000; Full time

Benefits offered by this job

Indefinite contract

Hybrid opportunity

Private health insurance

Flexible remuneration

Job summary

Multiverse Computing in Barcelona is seeking a Machine Learning Engineer to build data and model pipelines end-to-end, source datasets, augment data, and ship models that meet product and customer requirements. You will design evaluation frameworks, scale training and inference on distributed compute, and apply post-training optimization and safety improvements for NLP and compression workloads.

Collaboration with research and engineering teams is essential, with a strong ethics and diversity

Qualifications

• Bachelor’s degree in ML, CS, Math, Physics, or related field.
• Up to 2 years hands-on experience; Python and ML stack; basic software practices (git, unit tests, CI).
• Solid grounding in language modelling concepts around training, evaluation, architecture, and data.
• Experience using GPU resources and containerized workflows (Docker) and job schedulers or cloud orchestration.
• Ability to read research papers and turn ideas into reproducible production-ready code.
• Familiarity with AI/agentic workflows and task automation.
• PhD in ML, CS, Math, Physics, Data Science or related field, with NLP/LLMs experience (preferred).
• Experience building foundational LLMs and distributed training or model compression (preferred).

Responsibilities

• Build data and model pipelines end‑to‑end: create, source, augment, and validate datasets; train/fine‑tune/evaluate; ship models.
• Design evaluation frameworks to verify task competence; implement statistical testing and reliability checks.
• Scale training and inference using distributed compute; optimize throughput/latency; pursue speedups.
• Improve models post‑training with SFT and reinforcement learning methods for safety and capabilities.
• Optimize and specialize models with compression techniques; meet performance and footprint targets.
• Collaborate across research and engineering and contribute to shared codebase; uphold standards.

Education

Bachelor’s degree in ML/CS/Math/Physics

PhD in ML/CS/Math/Physics/Data Science (preferred)

Tools

Docker

Git

CI

Job description

Multiverse Computing

Multiverse is a well-funded, fast-growing deep-tech company founded in 2019. We are the largest quantum software company in the EU and have been recognized by CB Insights (2023 and 2025) as one of the 100 most promising AI companies in the world.
With 180+ employees and growing, our team is fully multicultural and international. We deliver hyper-efficient software for companies seeking a competitive edge through quantum computing and artificial intelligence.
Our flagship products, CompactifAI and Singularity, address critical needs across various industries:

CompactifAI is a groundbreaking compression tool for foundational AI models based on Tensor Networks. It enables the compression of large AI systems—such as language models to make them significantly more efficient and portable.

Singularity is a quantum- and quantum-inspired optimization platform used by blue-chip companies to solve complex problems in finance, energy, manufacturing, and beyond. It integrates seamlessly with existing systems and delivers immediate performance gains on classical and quantum hardware.

You’ll be working alongside world-leading experts to develop solutions that tackle real-world challenges. We’re looking for passionate individuals eager to grow in an ethics-driven environment that values sustainability and diversity.

We’re committed to building a truly inclusive culture—come and join us.
As a Machine Learning Engineer, you will

• In general: Build data and model pipelines end‑to‑end: create, source, augment, and validate datasets; stand up training/fine‑tuning/evaluation flows; and ship models that meet product and customer requirements.

• Design rigorous evaluation frameworks to verify task competence and alignment; implement statistical testing, reliability checks, and continuous evaluation.

• Scale training and inference: make effective use of distributed compute, optimize throughput/latency, and identify opportunities for algorithmic or systems‑level speedups.

• Improve models post‑training: apply SFT and reinforcement learning methods to enhance model capabilities and safety.

• Optimize and specialize models: apply compression techniques to meet performance and footprint targets.

• Collaborate across research and engineering and contribute to our shared codebase; uphold engineering standards.

Required Qualifications

• This role requires a Bachelor’s degree in ML, Computer Science, Math, Physics, or related field.

• Upto 2 years of hands‑on experience. Strong programming skills in Python and the modern ML stack and basic software practices (git, unit tests, CI).

• Solid grounding in language modelling concepts around training, evaluation, model architecture, and data.

• Experience using GPU resources and familiarity with containerized workflows (e.g., Docker) and job schedulers or cloud orchestration.

• Ability to read research papers, prototype ideas quickly, and turn them into reproducible, production‑ready code.

• Familiarity with AI / agentic workflows, and task automation.

Preferred Qualifications

• PhD in ML, Computer Science, Math, Physics, Data Science, or related field, or equivalent industry experience in machine learning, data science, or related roles, with demonstrated experience with NLP or LLMs.

• Experience building foundational LLMs from the ground up.

Preferred qualifications by focus area:

• Model Evaluation: track record building task‑grounded evals for LLMs, implementing or extending evaluation harnesses; deep understanding of LLM capabilities and quirks, and their ties to architecture and training dynamics.

• Distributed Training: Hands‑on experience debugging multi‑node training, profiling/optimizing throughput and memory, and extending training frameworks like to new architectures or optimizers; comfort diagnosing flaky cluster issues.

• Model Compression: Strong mathematical background and experience with pruning, quantization, and NAS; ability to formulate and solve constrained optimization problems for accuracy/latency/footprint trade‑offs and to integrate results into production.

• Post‑Training: Theoretical and practical familiarity with RL theory, frameworks, and monitoring.

Perks & Benefits

• Indefinite contract.

• Equal pay guaranteed.

• Variable performance bonus.

• Signing bonus.

• We offer work visa sponsorship (If applicable).

• Relocation package (if applicable).

• Private health insurance.

• Flexible remuneration: hospitality and public transportation.

• Eligibility for educational budget according to internal policy.

• Hybrid opportunity.

• Flexible working hours.

• Language classes and discounted lunch options

• Working in a high paced environment, working on cutting edge technologies.

• Career plan. Opportunity to learn and teach.

• Progressive Company. Happy people culture

As an equal opportunity employer, Multiverse Computing is committed to building an inclusive workplace. The company welcomes people from all different backgrounds, including age, citizenship, ethnic and racial origins, gender identities, individuals with disabilities, marital status, religions and ideologies, and sexual orientations to apply.