About the job
Join Our Team as a Senior Product Engineer (AI)
At Plain, we're revolutionizing customer support for the next generation of B2B enterprises. Our goal is to create the fastest and most powerful platform that enables businesses to transition from reactive support methods to building genuine relationships with their customers.
Renowned companies like Cursor, Raycast, and Granola rely on Plain to centralize customer interactions, enhance team collaboration, and elevate workflows through advanced AI technology.
The landscape of B2B customer support is evolving dramatically, with AI paving the way for innovative customer engagement strategies. Support has shifted from being a disconnected, slow process to a cohesive, company-wide initiative that spans channels like Slack, Discord, and beyond. The traditional methods just can't keep up anymore.
This position is hybrid, requiring 3 days a week in our London office.
Your Role
Plain is in an extraordinary position, already powering support solutions for high-growth businesses with our incredibly fast and scalable platform. AI has been integral to our offering from day one, and now we’re committed to deepening its impact across all facets of modern customer support.
We are on the lookout for a Senior Product Engineer with a passion for customer success to elevate our AI initiatives. In this role, you will develop the infrastructure necessary for rapid, secure, and confident delivery of AI features, taking ownership of challenges from inception to execution and playing a pivotal role in crafting a category-defining product.
In this role, you will:
Take full ownership of AI functionalities, including agents, assistants, insights, and beyond—from concept through to production.
Design and implement backend services that support AI integrations and data pipelines.
Create robust APIs and abstractions for internal AI applications.
Enhance system scalability through caching, optimization, and processing patterns.
Contribute to the evolution of our AI infrastructure, including architecture, evaluation, and iteration pipelines.
Tackle complex challenges surrounding AI accuracy, reliability, and quality using rigorous quantitative methods.
Represent our work externally through writing, speaking engagements, and connections with the broader AI community.
This Role is Ideal for You If You...
Are an experienced backend engineer with a proven track record of shipping AI products in the era of OpenAI and Anthropic, particularly in text and data-intensive AI applications.
Possess a deep understanding of AI technologies and their applications in real-world customer support scenarios.

