Senior AI Platform Engineer - Build Scalable AI Features

plain - agencia creativa; Greater London; Hybrid; GBP 90,000 - 120,000; Full time

Job summary

Plain, redefining customer support for B2B, is seeking a Senior Product Engineer to advance our AI ambitions. You’ll build infrastructure to ship AI features quickly, safely and confidently, owning end-to-end problems and shaping a category-defining product.

Join a fast-moving startup with high ownership, where you’ll design backend services for AI integrations, APIs and data pipelines, focusing on reliability, performance and measurable impact.

Qualifications

• Experienced backend engineer with a track record shipping AI products in production.
• Hands-on experience with large language models and data-heavy AI applications.
• Able to design scalable backend systems for AI features.

Responsibilities

• Own and ship AI features such as agents, assistants, insights from concept to production.
• Design and implement backend services for AI integrations and data pipelines.
• Build robust APIs and abstractions for internal AI usage.
• Drive system scalability: caching, optimization, processing patterns.
• Evolve infrastructure for AI, including architecture and pipelines.
• Solve AI challenges around accuracy, reliability, and quality.
• Advocate for our AI work externally via writing, speaking, and community engagement.

Skills

Backend AI

LLM orchestration

LLM optimization

RAG architectures

AI observability

Product minded

Customer focused

Tools

Postgres

Agent frameworks

Job description

Plain, redefining customer support for B2B, is seeking a Senior Product Engineer to advance our AI ambitions. You’ll build infrastructure to ship AI features quickly, safely and confidently, owning end-to-end problems and shaping a category-defining product.

Join a fast-moving startup with high ownership, where you’ll design backend services for AI integrations, APIs and data pipelines, focusing on reliability, performance and measurable impact.