Senior Software Engineer

The Flex; España; Remote; EUR 70,000 - 110,000; Full time

Benefits offered by this job

Remote-first

Performance-based rewards

Competitive compensation

Job summary

Base360.ai is seeking a Senior Software Engineer to architect and scale a platform for short-term rental operators. You’ll build customer-facing products, automation engines, AI-powered workflows, and integrations with partners like Airbnb, Stripe, and Twilio.

You’ll work on a cloud-native, API-first backend and a frontend stack with React/TypeScript, designed for reliability, security, and global growth across multiple property management businesses.

Qualifications

• Strong experience building and owning production-grade software systems.

Responsibilities

• Design and develop scalable applications, services, and APIs powering reservations, pricing, and operations.

Skills

API design

Distributed systems

Cloud architecture

Production-grade software

AI/automation curiosity

Problem solving

Tools

Python

FastAPI

React

TypeScript

PostgreSQL

AWS

Docker

OpenAI APIs

Job description

About Us

Base360.ai is the AI operating system for short-term rental businesses, helping property managers run their operations on autopilot.

Born out of The Flex, a short-term rental operator that scaled to an eight-figure business using its own software, Base360.ai is now launching as a standalone platform for short-term rental operators worldwide.

We bring reservations, guest communication, pricing, payments, cleaning, maintenance, and reporting into one platform - helping operators automate manual work, reduce costs, increase revenue, and scale their portfolios.

We're looking for a highly ambitious Senior Software Engineer who wants to build systems that solve real problems at scale. You'll build, ship, automate, and deliver products that directly impact property managers, their teams, and their guests.

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 Build

As a Senior Software Engineer, you'll help architect and scale Base360.ai—the platform powering every aspect of a short-term rental business.

You'll build customer-facing products, automation engines, AI-powered workflows, integrations, and operational systems that help property managers grow without increasing their workload at the same rate.

Your work will span the entire short-term rental lifecycle: from listing distribution, pricing, and bookings to guest stays, property operations, and financial reporting.

Your Mission

Build the Core Platform

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

Create Powerful Automations

Build event-driven workflows that eliminate repetitive work—from scheduling cleaning after a booking to sending check-in instructions and generating owner statements.

Develop AI-Powered Systems

Use LLMs and AI agents to automate guest communication, triage maintenance requests, support pricing decisions, and help operators manage their portfolios more efficiently.

Design API-First Architecture

Create robust APIs that connect internal services, booking channels, third-party providers, and customer systems.

Integrate the Ecosystem

Build and maintain integrations with platforms including Airbnb, Hostaway, Stripe, Twilio, OpenAI, Google, and other strategic partners across the short-term rental ecosystem.

Scale Infrastructure

Deploy and manage cloud-native infrastructure designed for reliability, performance, and global growth across multiple property management businesses.

Solve Complex Operational Problems

Build Solutions For

• Real-time reservation and availability synchronization
• Dynamic pricing intelligence
• Smart lock access and key management
• Automated guest communication across channels
• Operational forecasting
• Cleaning and maintenance automation
• Owner reporting and financial workflows
• AI-powered monitoring and alerts

Move Fast and Own Delivery

Own projects end-to-end—from understanding an operator's problem to architecture, implementation, deployment, and ongoing improvement.

Bring senior engineering judgment to technical decisions, code reviews, and the reliability of 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 and owning 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 and reliable data models
• The ability to work independently and make sound technical decisions
• Strong problem-solving skills and a product mindset
• Curiosity about AI, automation, and operational efficiency
• A bias toward action, shipping, and learning from real users
• The ability to balance delivery speed with maintainability and reliability

Bonus Points For Experience With

• Short-term rentals, hospitality technology, or property management systems
• Multi-tenant SaaS platforms
• Marketplace businesses and booking channel integrations
• AI agents and workflow automation
• Event-driven architectures
• Supabase
• AWS serverless infrastructure

What Success Looks Like

Within Your First 12 Months

• Core short-term rental workflows are automated through systems you've built
• Property managers spend less time on manual administration
• Reservations, availability, payments, and operational data move reliably between systems
• New integrations are deployed and maintained reliably
• AI-powered workflows become part of customers’ everyday operations
• The platform supports more operators and properties while maintaining reliability and performance
• Base360.ai helps customers grow their portfolios, improve guest experiences, and operate more profitably

Why Join Us

Build Something Meaningful

Solve problems experienced daily by short-term rental operators, with direct access to The Flex's operations to test ideas and see their impact.

Extreme Ownership

Have the freedom and responsibility to make technical decisions and deliver systems that matter.

Small Team, Massive Opportunity

Work closely with the founders and directly influence the product and technical direction of Base360.ai.

Learn Faster

Solve real-world challenges across software, AI, automation, hospitality 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 a narrowly defined role with limited product involvement
• You need detailed instructions for every task
• You avoid ownership and accountability
• You're comfortable shipping work without taking responsibility for its quality

We're looking for someone who wants to help build the AI operating system for the short-term rental industry.