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.

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

We care more about capability than specific technologies, but our current stack includes:

- 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 general 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

We're not looking for someone to fill a position.

We're looking for someone to help build the future operating system of modern renting.

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📌 Software engineer (España)
🏢 The Flex
📍 España