Guillermo Schmithalter

LizzyAI · Software Engineer

Jun 2025 – Present · Remote

AI recruiting platform where candidates interview with an AI agent and recruiters get scored results.

I build the AI interview product end to end: voice and chat interviews across web, phone, WhatsApp and SMS in 10 languages, an AI meeting assistant that joins recruiters' calls and syncs a summary to their hiring systems, and candidate messaging with analytics dashboards. Underneath, I put OpenAI, ElevenLabs and AWS Bedrock behind one layer so the product isn't locked to a single vendor, and I design, build and maintain the container-based, serverless and event-driven backends on AWS. I also introduced AI-assisted development with Claude Code across the team, building the skills and plugins it runs on, and I build and maintain the Slack-based AI agents that serve sales, legal and product.

Haufe Group · Software Engineer

Mar 2021 – Jun 2025 · Barcelona, Spain

I built a serverless notification system that delivers email, push notifications and in-app feeds to web and mobile apps, and a real-time chat feature that scales automatically with usage. I managed the cloud infrastructure as code, keeping costs tied to real usage, set up monitoring that reduced downtime, and led technical design sessions, presenting features to stakeholders.

Nielsen Holdings · Data Engineer

Jan 2017 – Mar 2020 · New York, NY, USA

I built data pipelines combining large consumer datasets from many sources, delivered market-trend analyses that shaped decisions for retail and consumer-goods clients, and built business-intelligence dashboards for enterprise clients.