About Phaidra Phaidra builds AI agents for AI factories. As demand for AI grows, data centers need to get more out of the power and infrastructure they already have. Power, cooling, and compute are closely connected, and making them work efficiently is one of the biggest challenges in scaling AI. Phaidra builds AI agents that help data center operators understand their infrastructure, troubleshoot issues, and optimize how their facilities run. Our agents connect data across IT and OT systems, helping teams find problems faster and use existing resources more effectively. Operators use Phaidra to optimize performance, reliability, and efficiency. From helping technicians get to the root cause of an issue to optimize cooling and power allocation, our work helps data centers maximize tokens per watt. Phaidra was founded in 2019 by former Google, DeepMind, and Trane engineers. Our team brings deep experience in AI, cybersecurity, mission-critical cooling, data centers, and industrial controls. We believe deploying AI in production demands deep domain expertise. We work closely with our partners to tackle challenges around real-world infrastructure at gigawatt-scale. Our team has a track record of applying AI to the toughest problems. We achieved superhuman performance with DeepMind’s AlphaGo and cut the energy needed to cool Google’s data centers by 40%. We know AI deeply, and we know

how to apply
it in production for massive impact. Phaidra can only achieve its mission if we work well together. Our core values define how we do that: Agency, Velocity, Craft, and Truth. We look for people who embody these values. They help our team deliver excellence consistently and build an engaging, supportive culture. Phaidra is headquartered in the USA, but we are 100% remote with no physical office. We hire internationally with support from our partner, OysterHR. Our team is spread across the USA, Canada, the UK, Sweden, Spain, Portugal, the Netherlands, Singapore, Australia, and India. Who You Are Phaidra is looking for a curious and pragmatic Research Engineer with a passion for physics and a knack for writing robust code. You will work within our research team to develop advanced physics-based simulators, with a particular focus on thermodynamics and fluid mechanics. These simulators are key to enabling intelligent control systems that optimize performance in industrial environments. You thrive at the intersection of science and engineering—able to translate complex physical systems into computational models and build tools that power cutting-edge AI systems. **We are seeking teammates who are based in Spain, Portugal, or the UK. Responsibilities
• As a Research Engineer working on Physics Simulators, you will:
• Design and implement physics-based simulation models for thermodynamic and fluid systems.
• Translate governing equations and first-principles models into performant numerical code.
• Collaborate with AI researchers to integrate simulators with reinforcement learning agents and optimization pipelines.
• Validate simulators against real-world data and iterate to improve fidelity and stability.
• Be a power user and contributor to Phaidra's simulation and AI platform, enabling scalable, reusable experimentation.
• Document and communicate technical ideas clearly across teams. Key Qualifications
• 3-4 years of experience in research or applied engineering.
• Bachelor's or Master's degree in Mechanical Engineering, Chemical Engineering, Applied Physics, or related field.
• Strong understanding of thermodynamics and fluid mechanics and HVAC systems.




• Experience building simulation tools using numerical methods (e.g., finite difference, ODE/PDE solvers).
• Proficiency in Python and scientific computing libraries (e.g., NumPy, SciPy, SymPy, pandas).
• Familiarity with simulation or modeling frameworks (e.g., Modelica, OpenFOAM, COMSOL, EnergyPlus, or custom-built tools).
• Comfortable reading academic papers and implementing physics models from scratch.
• Share our company values: Agency, Velocity, Craft, Truth Preferred Skills & Experience
• Knowledge of controls and optimization techniques (e.g., PID, MPC, or RL).
• Experience with Modelica environments (e.g., OpenModelica, MapleSim, Dymola, Amesim, Modelon)
• Experience integrating simulation tools with machine learning workflows.
• Experience working with large-scale systems or infrastructure in energy, HVAC, or industrial automation. Familiarity with power systems is a plus.
• Familiarity with modern software engineering practices (Docker, Git, CI/CD). Our Stack
• Python, NumPy, SciPy, pandas, SymPy
• PyTorch, Ray, scikit-learn
• Docker, Kubernetes, Terraform
• GCP Onboarding In your first 30 days...
• You'll onboard into Phaidra's product and research ecosystem.
• You'll study our current modeling work, simulation tools, and customer use cases.
• You'll set up your environment and begin replicating existing physics models in code. By your first 60 days…
• You'll begin contributing to one or more simulator development projects.
• You'll work closely with researchers to define simulation specs and performance metrics.
• You'll review field data to inform model accuracy and validation criteria. By your first 90 days…
• You'll be actively developing, validating, and improving simulation modules.
• You'll have results from early experiments and have contributed code to core libraries.
• You'll be shaping the direction of simulator design and pushing the envelope of physics + AI integration. General Interview Process All of our interviews are held via Google Meet, and an active camera connection is required.
• Meeting with People Operations team member (30 minutes)
• Meeting with Hiring Manager (30 minutes)
• Modeling and Simulation Interview (90 minutes)
• HVAC Interview (45 minutes)
• Culture fit interview with Phaidra’s co-founders (30 minutes) We use Kula as our hiring platform. During your interview, Kula's AI Notetaker will record a transcript of the meeting to allow the interviewer to focus on the interview, not the note taking. Base Salary UK Residents:
• Tier 1 (London): 101,014 GBP
- 168,356 GBP
• Tier 2 (Manchester, Birmingham, Edinburgh, Bristol): 95,072 GBP
- 158,453 GBP
• Tier 3 (Smaller cities / rural areas): 89,130 GBP
- 148,550 GBP Spain Residents:
• Tier 1 (Madrid, Barcelona): €89,957
- €149,929
• Tier 2 (Valencia, Seville, Bilbao): €83,037
- €138,396
• Tier 3 (Smaller cities/ rural areas): €76,118
- €126,863 Portugal Residents:
• Tier 1 (Lisbon, Porto): €94,109
- €156,848
• Tier 2 (Coimbra, Braga, Aveiro): €89,957
- €149,929
• Tier 3 (Smaller cities/ rural areas): €83,037
- €138,396 In addition to base salary,



this position is eligible for equity. Final salary will be determined based on several factors, including a candidate’s qualifications, skills, competencies, experience, expertise, education and location. In some cases, final compensation may fall outside the posted range. Salary ranges are regularly reviewed and may be adjusted in response to market trends. Benefits & Perks
• Fast-paced, team-oriented environment where your work directly shapes the company’s direction.
• We are a 100% remote company.
• Competitive compensation & meaningful equity.
• Outsized responsibilities & professional development.
• Training is foundational; functional, customer immersion, and development training.
• Medical, dental, and vision insurance (exact benefits vary by region).
• Unlimited paid time off, with a required minimum of 20 days per year.
• Paid parental leave (exact benefits vary by region).
• Versátil stipends to support your workspace, well-being, and continued professional development.
• Company MacBook. Please note: Not all of Phaidra’s benefits and perks listed above apply to temporary employees such as interns. On being Remote We take a thoughtful and intentional approach to remote collaboration. Inspired by pioneers like GitLab, we embrace proven best practices to foster an exceptional remote work environment. Our culture is documentation-first, and we prioritize asynchronous communication to support focus and flexibility across time zones. While we value independence, we stay closely connected through tools like Slack and video conferencing. Weekly all-hands meetings help us align and build strong relationships, and we regularly host virtual team-building activities and social events to maintain a sense of camaraderie. Equal Opportunity Employment Phaidra is an Equal Opportunity Employer; employment with Phaidra is governed on the basis of merit, competence, and qualifications and will not be influenced in any manner by race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability, or any other legally protected status. We welcome diversity and strive to maintain an inclusive environment for all employees. If you need assistance with completing the application process, please contact us at [email protected]. E-Verify Notice Phaidra participates in E-Verify, an employment authorization database provided through the U.
S. Department of Homeland Security (DHS) and Social Security Administration (SSA). As required by law, we will provide the SSA and, if necessary, the DHS, with information from each new employee’s Form I-9 to confirm work authorization for those residing in the United States. Additional information about E-Verify can be found here. #LI-Remote To be considered for any position at Phaidra, you must submit an online application. This role will remain open until it is filled. Phaidra only hires individuals who are legally authorized to work in the specified location(s) above. We do not provide employment sponsorship. Candidates requiring visa sponsorship, either now or in the future, are not eligible for hire. Candidates who advance beyond the initial screening stage will be required to sign a Non-Disclosure Agreement (NDA) in order to continue through the interview process. All employment offers are contingent upon successful completion of employment authorization verification and applicable background checks, in accordance with local laws and company policies. WE DO NOT ACCEPT APPLICATIONS FROM RECRUITERS.

📌 Senior Research Engineer (España)
🏢 Phaidra
📍 España