Senior Full-Stack Engineer (Python + React)
$72,000–$72,000 year
HybridVilnius, Vilnius, Lithuania or Kaunas, Kaunas, Lithuania
Job Summary
Design, build, and operate the backend systems powering the Investigation Agent using LangGraph workflows, FastAPI services, Postgres, Redis, and Kubernetes. Develop the frontend surface with React, TypeScript, and shadcn/ui to surface agent reasoning and evidence for analysts. Own features end-to-end from spec to production, including eval harnesses and feedback loops in Langfuse to ensure model reliability. Collaborate with Product, Data Science, and Engineering to shape product direction and establish engineering best practices for agentic products. Champion an AI-native workflow by automating repetitive tasks with agentic coding tools like Claude Code or Cursor.
Required Qualifications
- Strong hands-on experience with Python
- Strong hands-on experience with FastAPI
- Strong hands-on experience with Postgres
- Strong hands-on experience with Redis
- Proven proficiency in deploying, managing, and operating services on Kubernetes within AWS environments
- Practical experience with latency monitoring, diagnostics, and system optimization
- Deep understanding of writing high-availability code designed to perform under heavy production load
- Fluency with agentic coding tools (Claude Code, Cursor, or equivalent) as a core part of the daily workflow
- Excellent holistic thinking and problem-solving skills
- Drive to shape the product direction rather than simply executing pre-defined tickets
- Excellent communication skills
- Collaborative mindset
- Capability to clearly articulate technical trade-offs to both technical and non-technical stakeholders
- Genuinely Full-Stack Mindset: An end-to-end feature ownership approach rather than a strict separation between backend and frontend roles
Desired Qualifications
- Production experience with LangGraph (or equivalent agent orchestration frameworks)
- Production experience with Langfuse (or equivalent LLM observability/eval tooling)
- Prior experience in Anti-Financial Crime (AML, fraud, compliance, or investigations tooling)
- Deep curiosity to go learn the domain fast
Hiring someone like this?
Get your role in front of qualified candidates on Sorce.