Callbook AI
AI collections agency for late stage portfolios
YC Summer 2026AI
About Callbook AI
Callbook AI is a collections agency operated by AI. We collect late stage portfolios by finding, contacting and negotiating with borrowers.
Founders
Diego Avellaneda
Founder
CEO at Callbook AI. Applied ML researcher with two peer-reviewed publications on deep learning and embedded systems (TinyML on-device deep learning for indoor tracking; low-cost embedded sensing, Elsevier). Master's in IoT applying TinyML to real-time truck telemetry 6+ years in embedded ML. Former Senior Software Engineer at CI&T, where he built Audi's e-commerce car-purchasing platform. Second-time founder
Daniel Martinez
Founder & Product
CTO at Callbook AI. CPO at Treble (YC S19). Leading B2B products for 5+ years.