Senior Backend Engineer – AI Platform (London, Hybrid)

Personio; Greater London; Hybrid; GBP 90,000 - 150,000; Full time

Benefits offered by this job

Competitive salary and equity

28 days holiday (increasing with tenor

Hybrid working model

20 Flex Days to work from anywhere in 

Job summary

Personio in London is hiring multiple Senior Backend Engineers for our AI team. You will design and build backend services and APIs powering the AI Assistant and agent experiences.

You will shape the platform underneath it, collaborate with ML engineers, own features end-to-end from problem to production, and help evolve the architecture in a fast-moving, world-class environment. This role suits a strong backend developer who enjoys working on scalable systems and applying practical AI without

Qualifications

• Backend engineer with production experience.
• Proficiency in Kotlin or Java and JVM stack.
• Experience designing and scaling APIs and distributed systems.
• Clear communication across engineering disciplines.

Responsibilities

• Design and build backend services and APIs for AI Assistant.
• Build underlying platform for agentic products across Personio.
• Own features end to end, from problem definition through to production.
• Work directly with machine learning engineers on retrieval, prompting, and model interaction.
• Make architectural decisions in a fast-moving domain.
• Collaborate with Product, Design, and the teams building AI features.

Skills

Backend engineering

API design

Distributed systems

Cross-team collaboration

Tools

Kotlin

Java

AWS Bedrock

Job description

Personio in London is hiring multiple Senior Backend Engineers for our AI team. You will design and build backend services and APIs powering the AI Assistant and agent experiences.

You will shape the platform underneath it, collaborate with ML engineers, own features end-to-end from problem to production, and help evolve the architecture in a fast-moving, world-class environment. This role suits a strong backend developer who enjoys working on scalable systems and applying practical AI without