Senior Machine Learning Engineer (AI Research Lab)

Manychat; Barcelona; Híbrido; EUR 70.000 - 90.000; Jornada completa

Descripción de la vacante

A leading Chat Marketing platform in Barcelona is seeking a Senior Machine Learning Engineer to join their AI Research Lab. This role involves defining tool stacks, preparing validation data, and collaborating with the Python Platform Team to deliver solutions. The ideal candidate has over 7 years of experience in production ML/LLM, strong skills in Python, and a track record of successful project delivery. The position includes comprehensive health insurance, a professional development budget, and flexible benefits packages.

Servicios

Comprehensive health insurance

Professional development budget

Flexible benefits package

Hybrid work and generous leave options

In-office perks, including free meals

Company-funded sport activities

Formación

• 7+ years of production ML/LLM experience in Python, from prototype to live service.
• Proven skill training classical models and building repeatable pipelines.
• Practical experience fine-tuning LLMs, implementing RAG pipelines, and conducting large-scale evaluations.

Responsabilidades

• Define the team’s tool stack and create clear interfaces with other squads.
• Partner with Product to solve user cases and propose technical metrics.
• Prepare validation data and set dataset requirements.
• Deliver solutions to production with the Python Platform Team.

Conocimientos

Production ML/LLM experience in Python

Training classical models

Prompt-engineering expertise

Fine-tuning LLMs

Pydantic for typed data models

Clean, well-tested code

Effective cross-team collaboration

Project delivery in fast-moving environments

Descripción del empleo

Senior Machine Learning Engineer (AI Research Lab)

Barcelona, Spain

Manychat is a leading Chat Marketing platform. We help businesses engage with their customers on Instagram, Facebook Messenger, WhatsApp, and Telegram.

Trusted by over 1 million brands in 170+ countries, we’re an official Meta Business Partner, backed by top investors, including Bessemer Venture Partners.

With 300+ teammates across international offices in Barcelona, Austin, Amsterdam, São Paulo, and Yerevan — Manychat helps businesses across the globe improve their ROI and grow faster.

Manychat’s AI Research team turns cutting-edge ideas into production features that automate millions of conversations every day. You’ll work side-by-side with a dedicated Python Platform team (they handle service scaffolding, scaling, and architecture) and partner closely with Product to make sure every ML/LLM workflow you ship solves real user problems and is continuously validated in the wild.

Define the team’s tool stack : data labeling, experiment tracking, workflow-as-code, and more, creating clear interfaces with other squads.

Partner with Product to solve user cases and propose technical metrics that act as leading indicators for product KPIs.

Prepare validation data : set dataset requirements, recommend improvements, and drive labeling strategies.

Select the optimal approach : classical ML, LLM chains, or agents, balancing quality, cost, available data, and expected load.

Deliver solutions to production with the Python Platform Team, refining service boundaries as you go.

Continuously enhance features through monitoring and user feedback from live traffic.

• 7+ years of production ML/LLM experience in Python, from prototype to live service.
• Proven skill training classical models (gradient boosting, tree ensembles, linear models) and building repeatable pipelines.
• Prompt-engineering expertise: designing, testing, and refining system/user prompts, few-shot patterns, tool calls, and guardrails.
• Practical experience fine-tuning LLMs, implementing RAG pipelines, vector search, and conducting large-scale evaluations.
• Solid grasp of pydantic for typed data models and validation in Python services.
• Clean, well-tested code with CI/CD, containers, observability, and performance tuning.
• Clear written and verbal communication; effective cross-team collaboration.
• Track record of independently delivering projects in fast-moving environments.

We care deeply about your growth, well-being, and comfort:

• 💙 Comprehensivehealth insurancefor both you and your family.
• 📚Professional development budgetfor conference tickets, online courses, and other relevant resources to help you grow.
• 🫶Flexible benefits packageto tailor perks that matters most for you.
• 🪴 Hybrid workandgenerous leave optionsto prioritize your work-life balance.
• 🍽️In-office perks, including free meals and snacks.
• 🤝 Company-fundedsport activities,annual offsites,andteam-building events.

Manychat is an Equal Opportunity Employer. We’re committed to building a diverse and inclusive team. We do not discriminate against qualified employees or applicants because of race, color, religion, gender identity, sex, sexual preference, sexual identity, pregnancy, national origin, ancestry, citizenship, age, marital status, physical disability, mental disability, medical condition, military status, or any other characteristic protected by local law or ordinance. This commitment is also reflected through our candidate experience. If you have individual needs that may require an accommodation during the interview process, please indicate this in your application. We will do our best to provide assistance throughout your interview process to ensure you’re set up for success.

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