David Lorenzo, technical founder and Fractional CTO

Hi, I'm David Lorenzo 👋

(but everyone just calls me Loren)

Product Engineer · Hands-on Technical Founder & CTO · Fractional CTO
I build products on the WhatsApp Business API

david@davidlorenzo.net · WhatsApp · LinkedIn · GitHub · Almería, Spain · Remote
20+ yrs full-stack engineering & leadership
€300K ARR bootstrapped on WhatsApp API
€1M ARR scaled & sold to Efficy (SumaCRM)
€2M/mo GMV scaled at Chicfy (from €300K)
Meta Certified: WhatsApp for Business Technical Implementation
Meta Certified WhatsApp for Business Tech. Implementation

Technical founder and hands-on CTO with 20+ years building and scaling SaaS products. I like software that is simple, useful and sustainable. 🛠️ In every CTO role, 80% of my work has been writing production code as a full-stack developer — while also owning architecture, technical strategy and hiring.

I've led product and engineering as CTO at two well-known startups: Chicfy (C2C fashion marketplace, acquired by Vinted), where we scaled monthly GMV from €300K to €2M with 1.5M users and 10M+ products; and SumaCRM (acquired by Efficy), where we reached €1M ARR and 3,000 paying customers with a four-person team.

I believe the best technical leaders stay close to the code. I talk to customers daily, turn conversations into product, and ship features people actually pay for.

🚀 ManyContacts

WhatsApp Inbox + AI

Most of my time right now goes into ManyContacts, a CRM and unified inbox built directly on the WhatsApp Business API. It helps sales and support teams manage leads and close deals through automations, AI agents, mobile apps and a public API.

I built it end-to-end — inbox, automations, AI agents, product research, sales, onboarding and support. Bootstrapped to €300K ARR and 200 paying customers, with no external funding.

Visit ManyContacts →

openwebhook.co

OpenWebhook — Free Webhook Inspector for Developers

Test and debug webhooks in seconds. No signup, zero setup — copy your unique URL and inspect requests in real time. Payloads never touch the server.

kanbanmail.co

KanbanMail — Sales Kanban for Gmail

Turn your inbox into a sales pipeline without leaving Gmail. Assign each email to a column, with labels kept in sync.

🎙️

AlmeriaTech Tech Talks · 2024

"How to found a startup as a developer: the honest guide"

The reality of founding a startup as a developer. An honest guide full of practical lessons

Need to build a digital product or an MVP? Looking for a Fractional CTO for your company?
Drop me a line — I love hearing ideas and building useful things. 🚀