[Hiring] Senior Ontology Engineer @Phaidra

Role Description

We are looking for a driven Ontology Engineer to own the internal ontology that powers Prism. You sit at the intersection of HVAC/EPMS domain expertise and software — you understand how chillers, cooling towers, CRAHs, pumps, and electrical power monitoring systems actually behave, and you can encode that understanding into a structured, machine-usable model.

You are bold and creative, with deep empathy for customers whose systems are messy, inconsistent, and rarely documented the same way twice. You will design, build, and expand significant parts of the ontology and the tooling around it, and you'll have the opportunity to make an immediate impact on how quickly and reliably we can onboard new customer systems onto our product.

You are curious and like to understand technologies and their tradeoffs in depth. You already have accumulated insight from hands-on work with building systems and their control, and you are committed to rolling up your sleeves and getting work done. You like partnering with engineers, solutions teams, and domain experts — learning from them, and letting them benefit from your expertise.

We are seeking teammates who are based in one of the following locations: USA or Canada (Eastern timezone preferred)

Responsibilities

• Own, maintain, and expand the ontology that defines the HVAC and EPMS components, tags, and relationships used across Prism.
• Collaborate closely with Solutions Engineers, AI Core, Product, and domain experts to ensure the model reflects both physical reality and how our AI needs to consume it.
• Own the end-to-end lifecycle of the Prism ontology — define, extend, refactor, version, and deprecate HVAC/EPMS component types, tags, and relationships.
• Model new equipment classes and cooling/power topologies as we enter new customer segments.
• Design and maintain the tooling, schemas, and pipelines for engineers and solutions teams to author, validate, and query the ontology.
• Build validation and consistency checks that catch modeling errors, ambiguous tags, and broken relationships before they reach production.
• Partner with the AI Core team on the configs and Domain Specific Language (DSL) that map customer systems onto the ontology.
• Establish and document standards and conventions for naming, tagging, and relationships.
• Act as the internal source of truth and reviewer for ontology changes.
• Collaborate in cross-functional initiatives with engineers, product managers, and domain experts.

Qualifications

• Strong domain knowledge of HVAC and/or EPMS systems.
• Demonstrated ability to model a complex domain into a structured, consistent, extensible form.
• Proven ability to independently own and deliver complex projects with high quality and reliability.
• Solid software engineering fundamentals.
• Good working knowledge of Python.
• Excellent communication skills.
• Familiarity with semantic modeling or building-data standards.
• Strong attention to consistency, naming, and data integrity.
• Good educational background in relevant disciplines.
• Shares our company values: Agency, Velocity, Craft, Truth.

Preferred Skills & Experience

• Hands-on experience with building automation, BMS/BAS, or industrial control systems.
• Experience designing a Domain Specific Language or configuration system.
• Experience with datacenter cooling and/or electrical power monitoring at scale.
• Experience with cloud services and event-driven data pipelines.
• Track record of successful collaboration with domain experts.

Onboarding

In your first 30 days...

• You will be immersed in an onboarding program that introduces you to Phaidra and our product.
• You will spend time across Engineering, Solutions, and Data Science.
• You will read parts of our handbook and familiarize yourself with our documentation culture.
• You will set up your development environment and work through an onboarding exercise.
• You will learn how a real customer install gets mapped onto Prism today.

In your first 60 days...

• You will have a solid understanding of what Phaidra does and how the ontology fits into the product.
• You will have built relationships with the engineers, solutions teams, and domain experts.
• You will complete the onboarding exercise and ship your first meaningful ontology change or tooling improvement.

In your first 90 days...

• You will be fully integrated with the team and cross-functional partners.
• You will independently own a new component class or subsystem modeling effort.
• You will have identified at least one gap or inconsistency in the current ontology.
• You will begin setting standards and sharing knowledge on modeling patterns across the company.

General Interview Process

• All of our interviews are held via Google Meet, and an active camera connection is required.
• Meeting with Operations (30 minutes) — Meet you, learn about your background, discuss what you're looking for, and cover formalities around your application.
• Domain & Modeling Interview (75 minutes) — A working session on HVAC/EPMS systems and how you'd model them.
• Culture fit interview with Phaidra's co-founders (30 minutes) — Alignment with Phaidra's values and mutual cultural fit.

Base Salary

• US Residents:
• Tier 1 (Largest highest-cost metros): 134,442 USD - 175,615 USD
• Tier 2 (Other major metros): 127,720 USD - 175,615 USD
• Tier 3 (Mid-sized metro areas): 120,998 USD - 166,372 USD
• Tier 4 (All other locations): 114,276 USD - 157,130 USD
• Canada Residents:
• Tier 1 (Vancouver/Toronto): 136,123 CAD - 187,169 CAD
• Tier 2 (Montreal): 127,048 - 174,691 CAD
• Tier 3 (Waterloo, Ottawa, Calgary): 108,898 CAD - 149,735 CAD
• Tier 4 (Smaller cities / rural areas): 99,823 CAD - 137,257 CAD
• In addition to base salary, this position is eligible for equity.

Benefits

• Fast-paced, team-oriented environment.
• 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).
• Flexible stipends to support your workspace, well-being, and continued professional development.
• Company MacBook.

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.

Equal Opportunity Employment

Phaidra is an Equal Opportunity Employer; employment with Phaidra is governed on the basis of merit, competence, and qualifications.

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).

#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.