Hey there, I'm João Santiago

October 2025 → current (7 months)

• • D3 Labs is an AI studio built on a single conviction: agents will replace most of what teams do today — and the winners will be those who move first.
• • We design, build, and deploy commercial and support AI agents that integrate directly into a team's workflow, turning hours of manual work into seconds of autonomous execution.
• • Our clients don't just automate tasks — they compound. Every agent shipped raises their output ceiling, shrinks their cost base, and widens the gap between them and their competitors.

August 2023 → July 2025 (almost 2 years)

• • Built the entire product from scratch: system design, backend, frontend, mobile app, CI/CD pipelines, and observability.
• • Scaled the platform from zero to 98,000+ users while staying hands-on with the codebase at every stage of growth.
• • Made all core architectural decisions, balancing speed of delivery with long-term reliability as load grew orders of magnitude.
• • Was responsible for the full technical roadmap and maintaining engineering standards across the team.
• • Tech Stack: NestJS, NextJS, React, ReactNative, AWS, GCP, Docker, Kubernetes, Kafka, Redis

October 2021 → June 2023 (over 1 year)

• • Worked as a full stack engineer on one of the world's most trusted fintech platforms, with a strong focus on backend systems for payments, fraud detection, and gateway integrations.
• • Contributed to high-throughput services handling millions of cross-border transactions monthly, where correctness and idempotency were non-negotiable.
• • Optimized critical payment flow endpoints, reducing latency and improving reliability across fraud detection pipelines.
• • Was responsible for designing and enforcing patterns of communication between internal services to improve performance and security.
• • Tech Stack: NestJS, NextJS, React, AWS, Docker, Kubernetes, Kafka, Redis

May 2021 → September 2021 (5 months)

• • Shipped production code from day one, contributing to backend services across payment and fraud detection pipelines.
• • Got hands-on with distributed systems at scale, working on infrastructure used by millions of users across the globe.
• • Tech Stack: NestJS, React, AWS, Docker, Kafka, Redis

July 2020 → December 2020 (6 months)

• • Worked on backend development within one of the most recognized engineering organizations in the world.
• • Built internal services following enterprise-grade software practices, with a focus on clean architecture and scalable system design.
• • Tech Stack: Java, Spring Boot, Docker, AWS