Full-Stack Product Engineer
Madrid, Spain / Portugal·Full-time·Added 3 months ago
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.
This job was published 3 months ago
The role
At The Flex, we believe renting a home should be as simple as booking a ride.
Our mission is to 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 systems, and creating seamless experiences for guests, landlords, and operators worldwide.
We're looking for a Full-Stack Product Engineer who thrives at the intersection of product, engineering, and execution.
This isn't a role where you'll simply implement tickets.
You'll identify problems, design solutions, build products, automate workflows, and help shape the future of the platform.
What you'll do
Take ideas from concept to production by designing, building, testing, and launching features that create measurable business impact.
Work directly with founders and operational teams to understand challenges and transform them into elegant software solutions.
Ship quickly, gather feedback, iterate, and continuously improve products based on real-world usage.
Design systems that eliminate manual work and allow the company to scale efficiently.
Develop operational dashboards, workflow engines, management platforms, and AI-powered tools used across the business.
Build integrations with platforms such as Airbnb, Stripe, Hostaway, Twilio, Google, and OpenAI.
Implement AI-powered features and workflows that improve productivity, decision-making, and customer experience.
Ensure systems remain reliable, secure, and scalable as the business grows internationally.
Tech Stack
Current technologies include:
Python
FastAPI
React
TypeScript
Supabase
PostgreSQL
AWS
OpenAI APIs
Stripe
Twilio
GitHub Actions
You don't need experience with every technology listed above, but you should be capable of learning quickly and adapting.
What Success Looks Like
Within your first year:
You've launched multiple high-impact features
Manual operational processes have been automated
Product development cycles are significantly faster
AI-powered workflows have been deployed across the business
Base360.ai has become a stronger competitive advantage for The Flex
This Role Is Not For You If
You prefer highly structured corporate environments
You only want to write code from predefined specifications
You avoid ownership outside your immediate responsibilities
You are uncomfortable moving quickly and adapting to change
If you love building products, solving real-world problems, and creating systems that scale, we'd love to hear from you.
#LI-Remote
Requirements
What we're looking for
Strong full-stack development experience
Experience building production-grade web applications
Strong understanding of APIs and databases
Product mindset and user-centric thinking
Ability to work independently and take ownership
Strong problem-solving skills
Excellent written communication
Nice to have
Experience with FastAPI
Experience with React and TypeScript
Experience with AI tools or LLM integrations
Startup experience
PropTech, marketplace, or SaaS experience
Pay & benefits
What you'll get
You'll have direct influence over product decisions, architecture, and company strategy.
Your work will impact thousands of users and properties across multiple countries.
You'll work closely with founders and gain exposure to engineering, product, operations, AI, and business.
Work from anywhere.
We're building quickly and looking for people who want to grow alongside the company.
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.
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