Senior Platform Engineer - Developer Experience

About the role

Personio is looking for a Senior Platform Engineer focused on Developer Experience. You will work on internal tooling, SDKs, and middleware that enable hundreds of developers across multiple product teams to ship faster and more reliably.

Key responsibilities

• Design and support platform solutions such as internal tools, standards, SDKs, and middleware for 300+ developers.
• Build and evolve the GraphQL middleware layer connecting front‑ends with back‑end services.
• Create internal tools and libraries to boost developer productivity and platform adoption.
• Establish standards and best practices for API design, service integration, and platform usage.
• Analyze and optimise platform systems for scale, performance, reliability, and developer experience.
• Collaborate with product teams to ensure seamless platform integration and maintain a strong feedback loop.
• Document platform capabilities and conduct internal training sessions.
• Drive technical excellence by simplifying architecture and managing technical debt.
• Own operational responsibilities for platform services, including on‑call participation.

Required profile

• 5+ years of experience in platform engineering or backend development.
• Strong programming skills in a JVM language (Kotlin, Java, Scala); Kotlin is a plus.
• Proven experience building production‑grade backend systems with a focus on reliability, performance, and maintainability.
• Engineering mindset aimed at reducing friction for other teams through tooling and automation.
• Experience with modern high‑availability platform practices, testing strategies, performance optimisation, and reliability considerations.

Required skills

• Kotlin
• Java
• Scala
• GraphQL
• API design
• Middleware development
• SDK development
• Performance optimisation
• Reliability engineering