Full-Stack Engineer (.NET​/React

Czechia (Remote-Friendly)
· Open to Global Candidates Full-time

Synthreo is the AI-native platform for Managed Service Providers. We give MSPs everything they need to launch an AI-as-a-Service business without hiring AI experts — from our no-code agent builder (Builder) to a white-label ChatGPT‑style portal (ThreoAI) that their clients actually use.

We’re a small, senior team shipping real products that MSPs deploy to thousands of end users. Our platform handles secure RAG pipelines, multi‑tenant isolation, and deep Connect Wise PSA integrations — the kind of infrastructure that lets our partners monetize AI without becoming AI companies themselves.

You’ll work across three core products:
ThreoAI (our client‑facing AI portal with real‑time SignalR streaming), Builder (our no‑code agent platform with drag‑and‑drop workflow UI), and Tenant Management (our admin console for authentication, customer management, billing, secrets management, and access control).

This role is backend‑heavy (~70–80%) with meaningful frontend work. You’ll design APIs and data models, then build the React UIs that consume them. No pixel‑perfect design work — we need someone who can ship functional admin interfaces, data grids, forms, and real‑time streaming UIs. You’ll work directly with founders and a senior team; expect high ownership and real impact from day one.

• Design and ship services in .NET 6–9/C# (ASP.NET Core, Minimal APIs, background workers/hosted services)
• Work with Apache Cassandra 5.0 for agent and conversation data (wide‑column design, partition/clustering keys, native vector search with SAI)
• Build and extend Tenant Management: authentication flows (JWT, OAuth 2.0, Azure AD), RBAC, secrets management, billing integration, and cross‑tenant access rules
• Build REST APIs with idempotent workflows, back‑pressure, and retry strategies; integrate with RabbitMQ for async pipelines
• Implement SignalR hubs for real‑time chat streaming and live updates
• Integrate with LLM providers via Azure AI Foundry SDK and AWS Bedrock SDK — implement function calling, manage token streaming, handle retries and fallbacks
• Collaborate with our Python agent execution engine — understand how agents are orchestrated, how tool calls flow between .NET and Python, and debug cross‑service issues

• Build and iterate on React 19 interfaces — admin consoles, data grids, forms, workflow builders
• Implement real‑time features using SignalR client for chat streaming and live data updates
• Work with Dev Extreme components for data grids and UI elements;
  React Flow for diagram/workflow visualization
• Write clean component code with React Hooks (use State, use Effect, use Callback) and Context API for state management

• Ship via Docker and Git Hub Actions to Azure Container Apps; contribute to Terraform infrastructure as needed

We hire based on skills, curiosity, and growth potential — not years of experience. If you’re excited about AI and can ship code, we want to talk.

• Solid experience building production systems in .NET/C# — you’ve shipped APIs and worked with data layers
• PostgreSQL experience: schema design, writing queries, understanding indexes. Experience with Dapper or similar micro‑ORMs is a plus
• Solid React experience: hooks, component architecture, state management. You can build functional UIs without hand‑holding
• Strong grasp of Design Patterns and SOLID principles — you write clean, maintainable code on both frontend and backend
• Distributed systems understanding: concurrency, async/await patterns, transactions, and consistency trade‑offs
• JWT authentication implementation on both server and client side
• CI/CD and Docker fluency
• LLM integration experience: working with AI model APIs (Azure OpenAI, AWS Bedrock, or similar), function/tool calling patterns, and token streaming
• Clear async communication skills — critical for remote collaboration

• Azure AI Foundry SDK and/or AWS Bedrock SDK experience
• Python proficiency — ability to read, debug, and collaborate on our Python agent execution engine
• SignalR — both hub implementation and client consumption
• Dev Extreme React…