Fullstack Software Engineer
Role summary
Build and scale AI agents that perform real-world tasks across thousands of SaaS integrations while supporting a rapidly growing AI product processing more than 600,000 tool calls per day.
This role is ideal for experienced Fullstack Engineers who have hands-on experience building AI agents, shipping production software quickly, and working directly with founders in a fast-moving startup environment.
Important
• Proven experience building or significantly modifying AI agent systems
• Strong Python and TypeScript experience
• Experience with AI-assisted development workflows
• Experience shipping production software rapidly
• Strong systems-thinking mindset
• Ability to work on-site in Warsaw or Munich preferred
• Full-time position
• Existing EU work authorization required
Job description
You will work directly with founders to expand agent capabilities, improve reliability, develop integrations, manage infrastructure, and deliver new features at high velocity. This role combines AI engineering, backend development, frontend development, infrastructure management, and product ownership.
The ideal candidate has already built AI agents, understands the challenges of runtime orchestration, memory systems, evaluation frameworks, and tool integrations, and is comfortable shipping production-ready solutions quickly.
Compensation:
• Competitive salary
• Meaningful equity package
Responsibilities
• Build and improve AI agent runtimes
• Develop tool orchestration and memory systems
• Design closed-loop verification and evaluation workflows
• Build integrations with third-party SaaS platforms
• Develop backend services and APIs
• Build frontend product features in React
• Manage infrastructure, scaling, and deployment processes
• Improve reliability and system performance
• Support rapid product iteration and experimentation
• Collaborate directly with founders on technical decisions
Required Skills
• Experience building AI agent systems
• Strong Python development experience
• Strong TypeScript development experience
• React development experience
• Experience with AI-assisted coding workflows
• Experience deploying production software
• Experience integrating external APIs and SaaS platforms
• Strong systems design and architecture skills
• Experience working in startup environments
• Strong problem-solving abilities
Technologies
• Python
• TypeScript
• React
• AI Agents
• LLMs
• Slack
• Microsoft Teams
• APIs
• OAuth
• Webhooks
• Modal
• Containers
• CI/CD
Nice To Have
• Founder or startup experience
• Open-source AI contributions
• LLM evaluation infrastructure experience
• Deep understanding of model architectures
• Experience with MCP servers
• Custom AI tooling development
• Infrastructure optimization experience
• Large-scale SaaS integration experience
Soft Skills
• High ownership mentality
• Bias for action and shipping
• Strong communication skills
• Systems-thinking mindset
• Adaptability
• Curiosity about AI technology
• Comfort with ambiguity
• Collaboration skills
• Product-oriented thinking
• Results-driven approach