Fullstack Engineer - Mid Level - Actions Team

We're looking for a Fullstack Engineer to join our Actions team in building the core infrastructure that powers our plugin platform. You'll create the UI components, integration layers, and security mechanisms that enable our customers to extend the platform with custom integrations while maintaining safety and flexibility across our 1,500+ customer base. This is essential infrastructure work that shapes how our customers scale their integrations.

Our environment

• Working with skilled and like-minded professionals in a team that values diversity and inclusivity
• We aim to create a flexible and agile work environment that promotes the well-being and work-life balance of our employees
• We believe that team events during working hours play a vital role in building an exceptionally effective team, and we encourage them
• We are enthusiastic about technology and committed to using it to improve the world
• We follow the “You build it, you run it” approach and take pride in it

The Team

The Actions team sits at the heart of Staffbase's AI ambitions. We're the team that gives Navigator — our AI assistant and the main entry point into Staffbase — the ability to actually do things: submit a form, complete a task inside an integration, or take an action on a user's behalf through the agent. If Navigator is the brain, we build the hands.

That means two big things. First, we enrich what the AI can see and act on, our plugins, our widgets and the wider Staffbase platform so the assistant can do real work, not just talk about it. Second, we build the extensions that connect to the tools people already use, like Workday, Personio, ServiceNow and Microsoft. We're not just shipping features, though. A core part of our mission is building the extensibility framework that lets others build too.

What you'll be doing

• Building a UI component library that generated apps can assemble from, turning components like payslip views and approval flows into maintained, reusable pieces instead of regenerated artifacts
• Creating the connection layer between generated apps and customer source systems—HR platforms, time-tracking and scheduling systems, and a long tail of vendors with thin or undocumented APIs
• Defining extension points (widgets, menus, sidebars) so plugins declare where they surface and what they connect to in a single, clean configuration
• Designing and implementing a cross-integration authentication solution that lets customers run multiple integrations without forcing employees to log in repeatedly
• Shipping plugins on the platform yourself, staying a consumer of what we build so we catch gaps early

What you need to be successful

• Strong knowledge of React and TypeScript for frontend work Java/Kotlin or Go an TypeScript experience for backend services
• Real experience integrating third-party APIs, especially the challenging ones—inconsistent auth, partial documentation, legacy and on-prem systems
• Deep understanding of multi-tenancy security and data isolation; you care about scope checks and preventing cross-tenant leaks
• Good judgment about what to standardize and what to leave flexible—drawing that line in the right place is central to this role

Nice to have experience

• You are comfortable with edge and serverless runtimes like Cloudflare Workers
• You have built a plugin system, SDK, or developer platform before
• Developed a design system or component library that other teams depended on
• Real-world experience with OAuth and enterprise SSO
• Experience treating AI code generation as a product surface, not just a personal tool

What you'll get

• Competitive Compensation - we offer attractive salary packages including LTIP (unit-based Long Term Incentive Plan)
• Flexibility - we offer flexible working time models and the option of hybrid work, and support this with a yearly flex work allowance of €1560
• Recharge - with 31 vacation days annually (incl. one floating holiday), plus pro rata fully paid Fridays off during August
• Support - we offer offering a company pension scheme
• Volunteers Day - you’ll get one day off per year for supporting a social project