Software Engineer

The Flex; Netherlands; On-site; EUR 70,000 - 100,000; Full time

Benefits offered by this job

Performance-Based Rewards

Remote-First Work Environment

Extreme Ownership

Job summary

The Flex is looking for a Founding Software Engineer to help architect and scale Base360.ai, an innovative platform for modern renting. In this role, you will design scalable applications, build automations, and develop AI-powered systems that enhance guest experiences and streamline operations.

This position offers the chance to make a significant impact on the way people live and manage properties globally, while enjoying the flexibility of working from anywhere.

Qualifications

• Strong experience building production-grade software systems.
• Experience with FastAPI, Python, React, or similar frameworks.
• Ability to work independently with minimal supervision.

Responsibilities

• Design and develop scalable applications, services, and APIs.
• Build event-driven workflows that automate tasks.
• Leverage AI to streamline operations and improve decision-making.

Skills

Production-grade software systems

FastAPI

Python

React

APIs and distributed systems

Cloud architecture

Problem-solving ability

Curiosity about AI and automation

Tools

Supabase

PostgreSQL

AWS

Docker

Job description

At The Flex, we believe renting a home should feel as effortless as booking a ride.

Our mission is ambitious: enable anyone to live anywhere, anytime, without friction. Powered by Base360.ai, our proprietary automation platform, we are building the operating system for modern renting—connecting property data, orchestrating operations, automating workflows, and enabling seamless stays across continents.

We’re looking for a highly ambitious engineer who wants to build systems that create leverage at scale. This isn’t a role where you’ll spend months debating specifications. You’ll build, ship, automate, and solve real-world problems that directly impact thousands of guests and properties.

What You'll Build

As a Founding Software Engineer, you’ll help architect and scale Base360.ai—the technology platform powering every aspect of The Flex. You’ll build internal products, automation engines, AI-powered workflows, integrations, and operational systems that eliminate manual work and allow the business to scale globally. Your work will touch everything from guest journeys and property operations to pricing intelligence and AI-driven decision-making.

Your Mission

Build the Core Platform

Design and develop scalable applications, services, and APIs that power bookings, pricing, payments, guest experiences, and operations.

Create Powerful Automations

Build event-driven workflows that automate tasks previously performed by humans.

Develop AI-Powered Systems

Leverage LLMs, AI agents, and machine intelligence to streamline operations, improve decision-making, and enhance customer experiences.

Design API-First Architecture

Create robust APIs that enable seamless communication between internal systems, third-party providers, and future products.

Integrate the Ecosystem

Build and maintain integrations with platforms including Airbnb, Hostaway, Stripe, Twilio, OpenAI, Google, and other strategic partners.

Scale Infrastructure

Deploy and manage cloud-native infrastructure designed for reliability, performance, and global growth.

Solve Complex Operational Problems

Build solutions for:

• Real-time reservation synchronization
• Dynamic pricing intelligence
• Smart key management
• Automated guest communication
• Operational forecasting
• Cleaning and maintenance automation
• AI-powered monitoring and alerts

Move fast—own projects end-to-end, from idea to deployment and continuously improve the systems you build.

Tech Stack

• Python
• FastAPI
• React
• TypeScript
• Supabase
• PostgreSQL
• AWS
• Serverless Architecture
• OpenAI APIs
• Twilio
• Stripe
• Docker
• GitHub Actions

You Might Be a Great Fit If You Have

• Strong experience building production-grade software systems
• Experience with FastAPI, Python, React, or similar frameworks
• Strong understanding of APIs, distributed systems, and cloud architecture
• Experience designing scalable backend systems
• Ability to work independently with minimal supervision
• Strong problem-solving ability and product mindset
• Curiosity about AI, automation, and operational efficiency
• A bias toward action and shipping

Bonus Points for Experience With

• Property technology (PropTech)
• Marketplace businesses
• AI agents and workflow automation
• Event-driven architectures
• Supabase
• AWS serverless infrastructure

What Success Looks Like

Within Your First 12 Months

• Core operational processes are automated through systems you’ve built
• Manual work across the business is significantly reduced
• New integrations are deployed and maintained reliably
• AI-powered workflows become part of everyday operations
• Base360.ai becomes a competitive advantage that enables rapid global scaling

Why Join The Flex

Build Something Meaningful: your work will directly impact how people live, travel, and experience cities around the world.

Extreme Ownership: you’ll have the freedom to make decisions and build systems that matter.

Small Team, Massive Opportunity: work closely with founders and have a direct influence on product and technical direction.

Learn Faster: you’ll solve real-world challenges across software, AI, automation, operations, and scale.

Performance-Based Rewards: competitive compensation with substantial upside for exceptional performers.

Remote-First: work from anywhere. We care about outcomes, not hours.

This Role Is Not For You If

• You’re looking for a slow-paced corporate environment
• You prefer maintaining systems rather than building them
• You need detailed instructions for every task
• You avoid ownership and accountability
• Good enough is your standard