Principal Software Engineer

Invisible Technologies; City Of London; Hybrid; GBP 75,000 - 100,000; Full time

Job summary

A leading AI solutions company based in London seeks a Principal Software Engineer to design ML-powered tools and develop scalable backend systems. This role involves client collaboration, model optimization, and overseeing cloud operations. Ideal candidates should have over 5 years of software engineering experience focused on machine learning, along with strong Python and full-stack development skills. This position offers competitive compensation and a dynamic work environment.

Benefits

Competitive salary

Bonuses and equity offerings

Flexible working conditions

Qualifications

• 5+ years of software engineering experience focused on ML.
• Proven expertise in LLMs and ML model development.
• Experience with deployment of scalable ML systems.

Responsibilities

• Contribute to the Forward Deployed Engineering team.
• Optimize cloud infrastructure for ML models.
• Collaborate with clients for use case discovery.

Skills

Machine Learning engineering

Full-stack development

Python

Cloud platforms expertise

Kubernetes

Communication skills

Tools

AWS

GCP

Azure

Job description

About Invisible Technologies

Invisible Technologies is the AI operating system for the enterprise. Our end-to-end AI Software Platform structures messy data, builds digital workflows, deploys agentic solutions, evaluates/measures impact, and mobilizes relevant human experts. We have trained foundation models for more than 80% of the world’s leading AI model providers, including Cohere, Microsoft, and AWS, and we customize AI for any industry, function, or use case. In 2024, we reached $134M in revenue and were named the #2 fastest growing AI company on the Inc. 5000.

About The Role

We are seeking a highly skilled Principal Software Engineer with a strong background in full-stack development, particularly in backend technologies and Agentic AI, to join our AI/ML team. You will work at the intersection of engineering, data science, and real-world impact, partnering directly with clients and internal stakeholders to design and deploy ML-powered tools that solve meaningful problems. This role combines hands-on model development with robust backend engineering and infrastructure work, building scalable systems, supporting R&D initiatives, and ensuring rapid iteration and deployment of machine learning solutions in production-ready environments.

You will collaborate with top client teams to conduct use case discovery with senior stakeholders on-site 3-4 days a week in New York or London, and develop solutions that address complex client needs.

What You’ll Do

• Contribute as part of the Forward Deployed Engineering team during rapid growth, focusing on scaling models, improving platform performance, building backend systems, supporting client-facing deployments, and enabling smoother workflows for ML solutions.
• Develop and maintain AI/ML systems: build robust, scalable backend systems that support ML operations and data processing pipelines.
• Cloud operations and management: oversee and optimize cloud infrastructure for efficient deployment and operation of ML models.
• Problem solving: independently explore and address complex problem spaces to improve system capabilities and performance.
• Cross-functional collaboration: work with ML engineers and data scientists to integrate advanced ML technologies across platforms.
• Client engagement: collaborate directly with Invisible’s clients, embedded with client teams to support use case discovery, product development, and AI deployment.
• Innovation and R&D: participate in R&D of new tools to enhance AI capabilities and workflows.

What We Need

• 5+ years of software engineering experience with a strong focus on ML engineering and deploying machine learning models in production.
• Extensive experience in full-stack development, especially backend environments serving AI/ML workloads.
• Direct experience working with clients in use case discovery, product development, and leading client engagements.
• Technical expertise:
• Proficiency in Python with deep expertise in LLMs, AI Agents, and ML model development.
• Experience designing and deploying scalable ML systems, such as retrieval-augmented generation (RAG) pipelines and production-grade AI applications.
• Experience with cloud platforms (AWS, GCP, Azure) and operational best practices for ML workloads.
• Familiarity with Kubernetes and container management tools.
• Ability to write well-structured code and automated unit/E2E tests.
• Comfort with polyglot persistence models (SQL vs. NoSQL).
• ML Operations: experience with MLOps frameworks and DevOps practices for ML models, including model versioning, monitoring, and lifecycle management.
• Independent problem-solving in unstructured environments with a proactive, investigative approach.
• Excellent communication skills for collaboration in dynamic, cross-functional teams.

What’s In It For You

Invisible is committed to fair and competitive pay that reflects market conditions and the value each team member brings. Our salary structure accounts for regional cost of living and internal equity.

An Invisible Talent Acquisition Partner can provide information on geographic pay tiers during the interview process. For candidates outside the U.S., compensation will be adjusted to reflect local market conditions and cost-of-living differentials.

Bonuses and equity are included in offers above entry level. Final compensation is determined by location, experience, skills, knowledge, internal pay equity, and market conditions. Details on total compensation and benefits will be discussed during the hiring process.

What It's Like to Work at Invisible

We operate at the intersection of advanced AI and human ingenuity, pushing the boundaries of what’s possible to unlock productivity and scale. Ownership is at the core of our work. You’ll build, innovate, and shape the future alongside world-class clients pushing the boundaries of AI. We expect bold ideas, relentless drive, and the ability to turn ambiguity into opportunity. The pace is fast, the challenges are big, and the growth is unmatched.

If you’re driven to create and thrive in dynamic environments, you’ll fit right in.

Apply for this job

To apply, please use the Invisible Careers portal. This job description is intended to describe the general nature and level of work performed; it is not an exhaustive list of responsibilities, qualifications, benefits, or working conditions.

Equal Opportunity Statement: Invisible is an equal opportunity employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, national origin, disability, or veteran status, or any other basis protected by law.