Founding Software Engineer

The Flex; Denmark; On-site; DKK 900,000 - 1,600,000; Full time

Benefits offered by this job

Remote-first

Performance-based rewards

Job summary

The Flex is hiring a Founding Software Engineer to architect and build the Base360.ai platform, powering the future of the company and its global renting operations. You will work directly with the founder, influence product strategy, make architectural decisions, and own end-to-end systems from day one across bookings, pricing, payments, and guest experiences.

You will ship AI-powered workflows, integrate with partners such as Airbnb, Stripe, Twilio, and scale to international markets, driving

Qualifications

• Strong software engineering fundamentals.
• Experience building production-grade applications.
• Strong understanding of APIs, databases, and system design.
• Product mindset and customer obsession.
• Ability to work independently with minimal supervision.
• Strong problem-solving ability.
• High level of ownership and accountability.

Responsibilities

• Design, build, and launch the software powering bookings, pricing, payments, operations, communications, and guest experiences.
• Architect the long-term platform and make key technical decisions.
• Create automation at scale across multiple countries and thousands of stays.
• Develop AI-powered tools and workflows to improve productivity and experience.
• Integrate the ecosystem with partners like Airbnb, Hostaway, Stripe, Twilio, Google, OpenAI.
• Move quickly to turn ideas into production-ready solutions.

Skills

Strong software engineering

Production-grade apps

APIs & databases

Product mindset

Ownership & accountability

Independent work

Problem solving

Tools

FastAPI

React

TypeScript

PostgreSQL

AWS

OpenAI APIs

Stripe

Twilio

Docker

Job description

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

Our mission is ambitious: enable anyone to live anywhere, anytime, without friction.

Powered by Base360.ai, our proprietary technology platform, we are building the operating system for modern renting—automating operations, connecting fragmented systems, and creating seamless experiences for guests, landlords, and operators across the world.

We’re looking for a Founding Software Engineer to help architect and build the technology that powers the future of The Flex.

This is not a typical engineering role.

You’ll work directly with the founder, influence product strategy, make architectural decisions, and build systems that become the foundation of a global business.

You’ll have extraordinary ownership, responsibility, and impact from day one.

What You’ll Build

As a Founding Software Engineer, you’ll help create and scale Base360.ai—the technology platform that powers every aspect of The Flex.

From AI-powered workflows and booking systems to operational automation and intelligent decision-making, you’ll build products that directly impact revenue, efficiency, and customer experience.

You won’t just ship features.

You’ll create systems that replace manual work, unlock scale, and become a competitive advantage for the company.

Your Mission

Build Core Products

Design, build, and launch the software that powers bookings, pricing, payments, operations, communications, and guest experiences.

Architect the Platform

Make key technical decisions and help define the long-term architecture of Base360.ai.

Create Automation at Scale

Develop workflows and systems that automate operational processes across multiple countries and thousands of stays.

Leverage AI

Build AI-powered tools, agents, and workflows that improve productivity, decision-making, and customer experience.

Integrate the Ecosystem

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

Move Fast

Operate with urgency and ownership, turning ideas into production-ready solutions quickly and effectively.

Solve Real Problems

Work On Challenges Such As

• Reservation synchronization
• Dynamic pricing
• Smart access management
• Guest communication automation
• Operational forecasting
• Maintenance and cleaning automation
• AI-powered alerts and monitoring
• Revenue optimization

Help Build the Company

As one of the first engineers, your influence will extend beyond code. You’ll help shape processes, culture, product direction, and the future engineering team.

Tech Stack

Our Current Stack Includes

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

• We care more about your ability to learn and build than your experience with any specific technology.

What We're Looking For

Must Have

• Strong software engineering fundamentals
• Experience building production-grade applications
• Strong understanding of APIs, databases, and system design
• Product mindset and customer obsession
• Ability to work independently with minimal supervision
• Strong problem-solving ability
• High level of ownership and accountability

Bonus Points

• Startup experience
• Experience with AI products or LLM integrations
• Experience building SaaS products
• Experience with FastAPI, React, AWS, or Supabase
• Marketplace, travel, or PropTech experience

What Success Looks Like

Within Your First Year

• 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 Is Not For You If

• You’re looking for a predictable corporate environment
• You prefer maintaining systems rather than building them
• You need constant direction and supervision
• You avoid ownership outside your immediate responsibilities
• You are uncomfortable with change, ambiguity, and rapid execution

If you’re excited by building products, solving hard problems, leveraging AI, and helping create the operating system for modern renting, we’d love to hear from you.