Independent fractional CTO

Tomás Aguirre

I help seed and Series A teams ship the right thing without rebuilding their stack twice. Available for 8–12 week engagements.

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How I help

  • Architecture review

    2-week sprint from $9,500

    End-to-end review of your current system, technical debt, hiring plan, and the next two quarters of product. Closes with a written report and a 90-minute walkthrough.

  • Embedded fractional CTO

    Quarterly retainer from $14k/mo

    Two days a week with the founders and the team. Roadmap, hiring, vendor calls, code review, oncall escalations. Ends when you hire your first full-time CTO.

  • Pre-investor due diligence

    1-week sprint from $5,000

    I run the technical DD your investors are about to run — quietly, with you in the room, before the term sheet has consequences.

Track record

  • 11 Companies advised since 2022
  • $84M Aggregate Series A raised by clients
  • 92% Engagements that lead to a renewal or referral
  • <3wk Median time from first call to first deliverable

How we work together

  1. Free 30-minute call

    We talk through what's keeping you up at night. If I'm not the right fit, I'll usually know someone who is.

  2. Scoped proposal

    I send a one-page document with the engagement, the deliverables, and a fixed price. You can say no without owing me anything.

  3. Kickoff in 5 days

    Once we sign, I'm in your Slack and your codebase within a week. No long onboarding.

  4. Weekly written updates

    Every Friday: what changed, what's next, what's blocked. Async-first; meetings only when they earn their place.

About

I've been a startup CTO since 2014 — three companies, two acquisitions, one quiet shutdown that taught me more than the others. Before that, I was a backend engineer at **Stripe** and **Etsy**. I write [a newsletter](https://example.com/letters) for solo CTOs, and I live in Madrid with my partner and two cats.

Got a hard quarter ahead?

I take on three retainer clients at a time. I usually have one slot a quarter.