Senior FullStack engineer (AI-First)

Job description
 

About Fulcrum: We’re a team of tech-savvy, creative & passionate IT professionals. We’ve created a vibrant and performance-driven culture for ourselves where everyone is free to think & act outside the box. There are literally no limits to what you can do here, as long as we WOW our clients and OVER deliver what we promise.

 

Project overview

Our client is a UK-based product company working on an AI-driven platform that acts as a personal assistant capable of interacting with users and integrating with external tools such as email and other services.

The product is currently being built from scratch in an R&D environment with a strong focus on AI agents, rapid prototyping, and fast iteration.

We are looking for a Full-Stack Engineer (AI-First) who will help build the MVP and shape the technical foundation of the product.

The role combines full-stack development with AI-driven workflows. The engineer will design and implement core product functionality, integrate LLM-based capabilities, and orchestrate AI-driven pipelines.

The position requires a high level of ownership and comfort working in a fast-paced startup environment



Team composition - Product Owner, Full-Stack Engineer, Designer and QA

 

Key Responsibilities

- Design and develop core product functionality for an AI-powered platform with autonomous agents
- Build and improve the agent runtime that allows AI agents to execute tasks, interact with tools, and run in isolated environments
- Develop chat-based and conversational interfaces that enable users to interact naturally with their AI agents
- Implement and evolve the memory system that allows agents to learn from conversations and store long-term context
- Design and build APIs and backend services powering agents, integrations, and real-time features
- Work with vector databases and RAG pipelines to support intelligent retrieval and context building
- Build real-time experiences (streaming responses, live updates) for interactive agent execution
- Participate in building the multi-agent orchestration layer, enabling collaboration between multiple AI agents
- Contribute to the AI tool ecosystem, integrating external services and building extensible agent skills
- Collaborate with product, design, and engineering teams to iterate quickly and deliver new features

 

Job requirements

- 5+ years of experience in software development.

- 3+ years of experience with JavaScript / TypeScript
- Strong experience with React (React 18+) and Node.js
- Experience building applications with Server-Side Rendering (SSR)
- Experience developing REST APIs
- Experience integrating LLM APIs (OpenAI, Anthropic, or similar)
- Experience working with databases (experience with SurrealDB or similar NoSQL databases is a plus)
- Experience with Redis or streaming systems (e.g., Redis Streams), also Docker and containerized environments
- Experience with Git-based workflows and CI/CD pipelines
- Understanding of basic security principles in web applications
- Ability to work in an AI-powered development workflow (using modern AI tools in development), with AI agents / agentic systems
- Experience with Own Agent Building

Nice-to-have skills

- Experience working with multi-agent systems (agent orchestration, task delegation, agent-to-agent communication)
- Experience building RAG pipelines and working with vector databases (pgvector, Pinecone, Weaviate, SurrealDB vector)
- Experience integrating MCP (Model Context Protocol) servers or building extensible agent tools
- Experience with real-time communication (Server-Sent Events, WebSockets, Redis Pub/Sub)
- Experience with browser automation tools such as Playwright or Puppeteer
- Experience deploying applications in container-based cloud environments (Railway or similar platforms)
- Experience building modern UI systems using Tailwind and component libraries (e.g., shadcn/ui)

 

Hiring process

 

• Recruiter interview (40 min)
• Technical interview

• Final interview with PO and CTO
  
  
  
  What we offer:
  
  - Flexible schedule & opportunity to work remotely or workspace in Kyiv (kooperativ.cc);
  - Friendly & open team who have fun creating cool projects together;
  - Opportunity to boost your professional & personal growth;
  - Regular team gathering activities;
  - 20 business days of paid vacation + UA national holidays;
  - Medical insurance full coverage;
  - 10 + 5 days paid sick leave;
  
   

  How we operate:
  
  - We promise dramatic professional growth & interesting work
  - Bring ideas that will change how Fulcrum operates, and you will receive our gratitude and rewards
  - Your opinion matters. Fulcrum is not a typical ’bureaucratic company, and our employees are our core value
  - Your compensation grows with your responsibility zone
  - If something doesn’t go smoothly or can be simplified, just let us know — you are welcome to do so
  - You have a say in everything we do, starting from the roadmap, creating requirements, sprint planning, etc.
  - If you feel that everything above is about you, get in touch. We’re always glad to welcome stubborn, enthusiastic, and result-oriented buddies to our team
  
  
  
  Are you interested in working with us?
  
  LET’S MOVE THE WORLD TOGETHER!