Staff / Principal Research Scientist - UK

About the Position

Staff / Principal Research Scientist - UK

Inworld is a research lab of top researchers and engineers, building the world’s top-ranked realtime voice models. Our models power the largest consumer-facing AI applications across various categories, representing hundreds of millions of end users. We’ve raised more than $125M from prestigious investors and have been recognized as one of the most promising AI companies globally.

Who We're Looking For

We’re seeking strong individuals from varied backgrounds who learn fast, thrive in ambiguity, and can demonstrate their capabilities through their work. We value evidence and practical experience over traditional credentials.

Experience We Find Useful

• Foundation models: training, new architectures, RL, reward modeling, scaling
• Evaluation: benchmarks, eval loops, quality measurement, LLM-as-judge, failure analysis
• Frontier topics: multimodal models, agents, tool use, test-time compute, world models
• Published research at ICML, ICLR, NeurIPS, EMNLP, ACL, or AAAI
• PhD in ML/NLP - or equivalent practical experience
• Public work: non-trivial AI side projects, interdisciplinary experiments, open-source contributions
• Full-stack research ownership: framing questions, running experiments, writing papers, shipping results

Who Thrives Here

• Pathfinders: Comfortable picking a direction and building the map as you go.
• Full-Cycle Researchers: Believe research isn't finished until it’s shipped.
• First-Principles Engineers: Obsess over the why and question approaches for better solutions.
• Mission Owners: Thrive on deep context and understanding the fundamental logic behind decisions.

What Working Here Is Like

We hand you unclear problems and expect you to make them clear. We value researchers who say "I don't know yet" and then design the experiment that finds out. Evaluation is treated as a first-class research product. Impact comes before publications, though we support sharing work that moves the field forward. Your work should be visible. We have a flat structure, fast iterations, and minimal process theater.

Salary

The base salary range for this full-time position is £140,000 – £200,000. In addition to base pay, total compensation includes equity and benefits. Within the range, individual pay is determined by work location, level, and additional factors, including competencies, experience, and business needs. The base pay range is subject to change and may be modified in the future.

Requirements

• Location: United Kingdom
• Employment Type: Full-time
• Experience Level: Senior
• Skills: Machine Learning, Natural Language Processing, Research, Deep Learning, AI

We Offer

• Competitive salary range of £140,000 – £200,000
• Equity and benefits
• Opportunity to work on state-of-the-art realtime voice models
• Flat structure, fast iterations, minimal process theater

About the Company

Inworld is a leading AI research lab building the world’s top-ranked realtime voice models. Our technology has powered experiences from companies such as NVIDIA, Microsoft Xbox, Niantic, Logitech Streamlabs, Wishroll, Little Umbrella, and Bible Chat. We’ve been recognized by CB Insights as one of the 100 most promising AI companies globally and have been named one of LinkedIn’s Top 10 Startups in the USA.

Candidates must already have the legal right to work in the United Kingdom, as visa sponsorship is not available for this role. For candidates interested in relocating to the San Francisco Bay Area in the future, full U.S. visa and relocation support may be available, subject to business needs and applicable legal and work authorization requirements.