Founding Software Engineer

About the role

At The Flex, you will architect and build the foundational technology that redefines how people rent and live in homes. You will own critical product modules end to end, turning high-level ambitions into reliable, production-grade systems. You will partner directly with the founder to shape product strategy and prioritize work that moves the business forward. You will leverage cutting edge tools to solve messy real-world problems in property management and travel. You will be responsible for delivering automation that scales across borders and property types from day one. You will have the freedom to make technical decisions that define the long-term architecture of the platform.

Key facts

What you'll do

• Design and build the core products that power bookings, pricing, payments, operations, communications, and guest experiences across the platform.
• Architect the Base360.ai technology stack and define long-term scalability, reliability, and security standards for the renting operating system.
• Create AI-powered workflows and intelligent agents that automate operations, reduce manual effort, and improve decision-making for landlords and guests.
• Develop and maintain deep integrations with Airbnb, Hostaway, Stripe, Twilio, Google, OpenAI, and other strategic partners to ensure seamless data and payment flows.
• Implement systems for reservation synchronization, dynamic pricing, smart access management, and guest communication automation that work reliably at scale.
• Build operational forecasting, maintenance, and cleaning automation tools that optimize resource allocation and reduce friction for operators.
• Deliver AI-powered alerts, monitoring, and revenue optimization features that enable proactive management and better financial outcomes.
• Move fast to prototype, test, and deploy production-ready solutions while maintaining high standards for code quality and reliability.
• Collaborate closely with product and operations teams to translate complex requirements into elegant technical solutions.
• Act as a technical leader for the engineering culture, helping to define processes, code standards, and product direction from the ground up.

Requirements

• Must have a strong foundation in software engineering fundamentals, including algorithms, data structures, and system design.
• Must have experience building production-grade applications that handle real traffic and data volumes.
• Must possess a deep understanding of APIs, databases, distributed systems, and end-to-end product architecture.
• Must demonstrate a product mindset with intense customer obsession and a drive to solve meaningful problems.
• Must be able to work independently with minimal supervision while still communicating progress and risks clearly.
• Must have strong problem-solving ability and comfort with debugging complex issues in distributed environments.
• Must take high levels of ownership and accountability for outcomes, not just tasks or tickets.
• Must be comfortable navigating ambiguity and making decisions in a fast-moving startup environment.
• Must be legally authorized to work in France without sponsorship, as no visa support can be provided for this role.
• Must be available to work full-time during standard business hours aligned with the Paris time zone.

Nice to have

• Previous startup experience helping build products and features from inception to launch.
• Hands-on experience with AI products, LLM integrations, or building tools on top of large language models.
• Experience building and scaling SaaS products in production environments.
• Familiarity with FastAPI, React, AWS, or Supabase in past projects or professional work.
• Background in marketplace platforms, travel technology, or PropTech industries.

What success looks like

• Critical company operations are automated through systems you've built.
• Base360.ai becomes a core competitive advantage.
• New products are shipped rapidly and reliably.
• Engineering velocity increases significantly.
• AI-powered workflows are embedded across the business.
• The platform is ready to scale internationally.

Why join The Flex

• MASSIVE IMPACT: Your work will directly shape how thousands of people live, travel, and experience cities.
• FOUNDING-LEVEL OWNERSHIP: You'll have significant influence over product, technology, and company direction.
• BUILD ALONGSIDE THE FOUNDER: Work closely with leadership and help define the future of the business.
• LEARN FASTER: Gain exposure to engineering, AI, product, operations, growth, and company-building.
• PERFORMANCE-BASED REWARDS: Competitive compensation with meaningful upside for exceptional contributors.
• REMOTE-FIRST: Work from anywhere. We care about results, not hours.

This role requires full-time on-site presence in Paris during standard business hours. No visa or sponsorship support is available for this position. The engagement is full-time, and the workload will require consistent availability during business hours.