Collybrix provides the strategic technical leadership your startup needs at the most critical stages: pre-seed and seed. Technical roadmap, scalable architecture, team leadership and investor readiness. No long-term contract.
CTO as a Service A (also called Fractional CTO or External CTO) is an experienced technology director who works with your startup part-time, bringing the same strategic vision as a full-time CTO but at a fraction of the cost.
Hiring a senior full-time CTO costs between €80,000 and €150,000 per year in gross salary, not counting stock options, social security and benefits. For most startups in the pre-seed or seed stage, that cost is unaffordable when capital must go toward product and customer acquisition.
With the Collybrix CTO as a Service model, you get high-level technical leadership — with 15+ years of experience building scalable systems and leading teams in startup ecosystems — for €1,500 to €8,000 per month depending on the required dedication.
Our external CTOs don't just write code: they define the technical strategy, lead the development team, make architecture decisions and prepare you for critical moments: the MVP launch, the investment round and post-seed growth.
We prioritize technical decisions that maximize impact on business metrics: conversion, retention, time-to-market.
We lead and mentor your development team to work with proven methodologies, faster and with fewer bugs.
We choose the right stack and architecture for your current and future stage, avoiding technical debt that hinders growth.
Technical due diligence without surprises. We prepare the technical documentation and storytelling that investors need to see.
15+ years of experience in startups means we know what works and what doesn't. We avoid costly mistakes from the start.
Monthly contracts, no minimum term. We scale up or down the dedication according to your startup's needs.
There are specific moments in a startup's life where external technical leadership makes the difference between scaling or stagnating:
Your startup needs a CTO as a Service when you have traction or a validated idea but can't afford a full-time CTO (salary €80,000-€150,000/year). Especially useful in pre-seed and seed stages, when you need to make critical technical decisions: what stack to choose, how to structure the development team, what architecture will support growth. If you're losing time on technical decisions or feel the development team lacks clear direction, it's time.
The cost varies according to the level of dedication. A typical CTO as a Service engagement is 2 to 4 days/week and ranges between €3,000 and €8,000/month, compared to €12,000-€15,000/month for a senior full-time CTO. For one-off projects of 1-2 days/week (technical roadmap, audit, due diligence), prices start from €1,500/month. Contact us for a proposal adapted to your stage.
An agency executes code. An external CTO decides what code to write and why. Collybrix's CTO as a Service brings strategic direction: defines the architecture, leads the technical team, prioritizes the roadmap based on the business, avoids technical debt and prepares the startup for investors and growth. It doesn't replace the development team — it directs and empowers it.
Yes, and in fact it's the strategy we recommend. Collybrix's CTO as a Service establishes the technical foundations, processes and engineering culture. When you're in Series A with proven traction, you'll be much clearer on what CTO profile you need to hire, and the candidate will find a technically solid company that is more attractive to senior talent.
Our service includes: (1) Initial technical diagnosis and audit of the current situation, (2) Definition and prioritization of the technical roadmap, (3) Technology stack and architecture selection, (4) Development team leadership and mentoring, (5) Technical vendor management, (6) Preparation for investor technical due diligence, (7) Participation in key meetings with stakeholders and board.
We work with startups across Spain and also with European startups with operations in Spain. We are based in Madrid but operate remotely for most clients. For Madrid-based startups we also offer regular in-person meetings.