CTO & Co-Founder - Proptech

Co-Founder & CTO Opportunity at Antai Ventures

Antai Ventures is a Barcelona-based venture studio with presence across Southern Europe and LatAm. We partner-up and invest in the best co-founders to build global companies willing to disrupt multi-billion dollar industries. Since 2012 we have co-founded +30 companies including Glovo, Wallapop, PlatanoMelon, and Piper. Our ventures have raised more than $1.5B in funding, have generated more than $3B in shareholders value and currently employ more than 3000 people.

We are building an AI-native platform for the real estate sector in Spain — one of the most fragmented, relationship-driven, and underdigitised industries in Southern Europe.

We have a validated product thesis, a clear go-to-market, and we're now looking for a co-founder & CTO to build it.

What You'll Do

• Build, launch and scale a disruptive product from scratch.
• Own the technical architecture — define the stack, set the engineering standards, and make the hard trade-offs between speed and scalability from day one.
• Design and implement a multi-agent orchestration layer — persistent state management, agent-to-agent handoffs, tool-calling pipelines, and context windows that don't collapse under real usage.
• Build and maintain LLM-powered workflows in production.
• Integrate third-party infrastructure (voice providers, CRMs, payment and signing APIs, document verification) into a coherent, maintainable system.
• Ship code daily — from prototype to production, you are hands-on throughout.
• Drive a culture of excellence through continuous delivery, rapid experimentation, and customer-obsessed iteration.

What We're Looking For

• Proven track record as a hands-on engineer, tech lead, or CTO in an early-stage environment.
• Hands-on builder. You prototype fast and turn ideas into working features in days, not weeks.
• Practical AI experience. You have built production systems with LLMs — agent orchestration, multi-agent workflows, conversational AI — and know what actually works outside a demo.
• Architectural thinking. You design systems that are simple enough to ship fast today and solid enough to scale tomorrow.
• Ownership mindset. You take responsibility for outcomes and think long-term about product and company value.
• Clear communicator. You can explain technical trade-offs to engineers and non-technical co-founders alike.
• Fluency in Spanish and English.

What We Offer

• Day-1 founding seat. Join an ambitious venture from the ground up, with a validated concept and Antai's full backing.
• Significant equity. Own a meaningful stake in the venture, plus optional carry in other Antai portfolio companies.
• Full-stack operator support. Access Antai's expert teams in Product, Engineering, Design, GTM, Legal, Talent, and Fundraising whenever you need them.
• Founder community and investors. Join a tight network of serial entrepreneurs and top-tier backers who have scaled category leaders.
• Based in Barcelona, hybrid.