Software Engineer

Madrid, Spain / Portugal·Full-time·Added 3 months ago

The Flex

6 open roles

What they offer

  • Full-time hours

    Per the ad.

  • Fully remote

    Per the ad.

What they ask for

  • Have the right to work in Spain

    The Flex doesn't mention sponsorship in the ad.

  • Work in English

    English is required, per the ad.

  • Have senior-level experience

    Senior-level role.

This job was published 3 months ago

The role

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.

If you're excited by APIs, automation, AI agents, cloud infrastructure, and building products from the ground up, we want to meet you.

What you'll do

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

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

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

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

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

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

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

Own projects end-to-end—from idea to deployment—and continuously improve the systems you build.

How you'll work

Work from anywhere. We care about outcomes, not hours.

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.

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 global scaling

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.

Learn Faster

You'll solve real-world challenges across software, AI, automation, operations, and scale.

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.


#LI-Remote

Pay & benefits

What you'll get

Competitive compensation with substantial upside for exceptional performers.

About The Flex

The Flex is a PropTech company operating in the real estate technology sector, focused on building software solutions for the property industry. The company is at an early stage, operating as a startup with a small, focused team. Their work centers on developing products that address challenges in the real estate market, leveraging technology to improve processes for property professionals.

The Flex has established a presence in Madrid, Spain, where they are actively hiring for their founding team. As a young startup, they offer international professionals the opportunity to join at the ground level, taking on significant ownership and responsibility in shaping the company's product and growth. Their work culture is likely dynamic and fast-paced, typical of early-stage startups, with a strong emphasis on engineering and product development.

Industry
PropTech
Employees
50
Headquarters
Madrid, Spain
In Spain
Madrid

Good to know if you are moving

  • Early-stage startup: joining now means you can have significant impact on the product and company culture.
  • Based in Madrid, Spain, offering a chance to be part of a founding team in the PropTech sector.
  • As a startup, the company may offer equity or other incentives to early employees, common in this stage of company growth.
  • The team is small, so roles are likely to be cross-functional and offer broad responsibility.
  • The company is building software for the real estate industry, a sector with global relevance.

In their own words

About the company & team

Work closely with founders and have a direct influence on product and technical direction.

All open roles at The Flex
WhatsApp