Backend Symfony Developer

This is a position at a startup at the scaling stage that requires experience working with LLM prompts and building workflows with them.

UpMarket is building a front automation SaaS for hotels and vacation rentals, blending classic business apps with LLM-based functionality. We need a developer with solid PHP and LLM prompt-crafting expertise to lead the next iteration of our LLM processing with an agent-based (service-oriented) architecture. Our stack is PHP 8, Symfony 6/7, MySQL, NextJS, and LangChain. Fully remote. The company is registered in the Netherlands. Salary range: €3500–5000/month, with negotiable equity.

Must Have

• 7–10 years of backend web dev experience
• Strong PHP background (preferably Symfony)
• Crafting, debugging, and refining LLM prompts for decision-making graphs
• Service-architecture skills (queue-based background processing)
• Ability to plan, architect, and execute projects independently, with potential to lead an LLM-focused sub-team
• Deep understanding of LLMs
• Good learning skills
• Significant CET overlap (standups at 09:30, weekly Monday meeting at 17:00)

Good to Have

• Senior or team lead experience
• ApiPlatform familiarity
• GraphQL experience
• Background in training LLMs for specialized tasks
• Solid SQL knowledge
• Symfony 6/7, ApiPlatform 4.x
• LangChain and NextJS for maintaining current functionality while building the next version