Senior Full-Stack Engineer (AI SaaS) $$$$

On behalf of our Client from Israel, Mobilunity is looking for a Senior Full-Stack Engineer on full-time engagement.

Our Client is developing a SaaS platform that evaluates how brands perform across LLMs and provides actionable insights to improve visibility and performance.

The system includes:
A user-facing SaaS platform (customer dashboard, insights, reporting) A data processing backend that interacts with multiple LLMs to generate analysis

Currently:
- Platform is live with ~20 paying customers
- Initial MVP was built quickly using a “vibe coding” approach → now undergoing restructuring and productionization
- Moving toward a more scalable, clean architecture with APIs and separated systems
- Future plans include expanding into automated implementation of recommendations

About the Team:

Looking for experienced proactive person who can take on tech leadership from current R&D developer and tackle next challenges:

• Existing codebase is messy and requires refactoring/re-architecture.
• Need to stabilize and scale a working but early-stage system.
• Managing two separate systems (frontend app + LLM data engine).
• Increasing need for complex integrations (LLMs, analytics tools, CRMs, enterprise systems).
• Lack of strong internal technical leadership to define roadmap and best practices.

Key Responsibilities:

• Own and improve overall system architecture (frontend, backend, data/LLM systems).
• Refactor and scale existing MVP into production-grade system.
• Hands-on full-stack development.
• Lead LLM integrations (APIs, prompting, orchestration).
• Build and maintain integrations (payment, CRM, analytics, erp, custom APIs).
• Work closely with founders on product and technical roadmap.
• Participate in hiring and mentoring future engineers.

Required Skills and Experience:

• 5+ years in full-stack development building and scaling SaaS products.
• Background in early-stage/startup environments refactoring or rebuilding MVP systems.
• Background working with data/AI-driven products.
• Strong full-stack skills (React/Vue + Node.js/Python or similar).
• Solid understanding of system architecture and scalability.
• Experience with API design and system integrations.
• Hands-on experience with LLM/AI integrations: OpenAI, Gemini, or similar APIs. Prompting and workflow design.

Nice-to-Have skills:

• Experience with domains related to SEO / eCommerce / marketing tech.
• Experience with enterprise integrations (Salesforce, ERP, etc.).
• Experience connecting 3d-party APIs & tools.

In return we offer:

• The friendliest community of like-minded IT-people
• Open knowledge-sharing environment – exclusive access to a rich pool of colleagues willing to share their endless insights into the broadest variety of modern technologies
• Mobilunity Medical Insurance program designed to attend our teams’ needs
• Paid vacations and sick leaves, including 5 paid days per year that don’t require a sick note
• Perfect office location in the city-center (900m from Lukyanivska metro station with a green and spacious neighborhood) or remote mode engagement: you can choose a convenient one for you, with a possibility to fit together both
• No open-spaces setup – separate rooms for every team’s comfort and multiple lounge and gaming zones
• English classes in 1-to-1 & group modes with elements of gamification
• Neverending fun: sports events, tournaments, music band, multiple affinity groups