
Vinicius Fernandes
@viniciusfernandes2
I build production LLM agents, RAG systems, and regulated payments data infrastructure.
What I'm looking for
I've built LLM-agent CRM automation at NuvixTech for multi-step WhatsApp Business API workflows, while co-founding Ambern to deliver WhatsApp AI agents, collections automation, and RAG systems for startups.
Across LINA, Sicredi, Hotmart, and Stone, I've delivered financial data and payment platforms: 74M+ mapped companies, 85% faster pipeline execution, 18% higher checkout conversion, and Pix reconciliation systems processing millions of daily events.
Experience
Work history, roles, and key accomplishments
Co-founded Ambern, a small AI/automation engineering studio positioned as "2 engineers for startups" for international clients. Focused on WhatsApp AI agents, billing/collections automation, and RAG-based systems. Running this in parallel with client work — open to new full-time opportunities.
AI / Backend Engineer
NuvixTech
Jan 2025 - Present (1 year 8 months)
Built data-driven backend systems and AI-assisted workflows for B2B operations.
• Developed lead-generation and data-processing workflows using Python, PostgreSQL and public business datasets.
• Built an LLM Agents–powered CRM automation using LangChain and LangGraph to orchestrate multi-step WhatsApp Business API workflows.
• Developed backend integrations connecting APIs, database state and busi
Senior Data Engineer / AI Engineer
LINA
Mar 2025 - Jul 2026 (1 year 4 months)
Designed and implemented data cross-referencing and enrichment pipelines for financial data via Open Finance, and developed AI/LLM pipelines including RAG for risk analysis and scoring.
Senior Data Engineer / AI Engineer – Open Finance & Financial Data
Mar 2025 - Jul 2026 (1 year 4 months)
Designed and implemented data cross-referencing and enrichment pipelines for financial data (Pix, accounts, credit) via Open Finance, on a platform serving 3,000+ active clients, mapping 74M+ companies across 30+ data sources with 80% validated accuracy.
Developed AI/LLM pipelines — including Retrieval-Augmented Generation (RAG) — for risk analysis, scoring, and insight generation from consented t
Architected batch and near real-time data pipelines supporting financial intelligence and regulatory compliance systems.
Key Contributions:
• Optimized high-volume SQL queries and Python processing jobs, reducing overall pipeline execution times by ~85%.
• Implemented automated data quality validation frameworks across core database tables, improving system reliability for audit readiness.
• Partn
Senior Fullstack / Data Engineer
Hotmart
Sep 2022 - Jun 2023 (9 months)
Led the evolution of checkout and payment systems, improving conversion rate by 18%, and built purchase-behavior and LTV data pipelines with AI solutions for fraud detection and product recommendation.
Led the evolution of checkout and payment systems (Pix + card), improving conversion rate by 18%.
Built purchase-behavior and LTV data pipelines, cross-referencing payment data with user engagement.
Implemented AI solutions for fraud detection and product recommendation (lightweight models + feature store).
Stack: Node.js/TypeScript · React · PostgreSQL · Kafka · Python · DBT · AI applied to fraud
Senior Backend / Data Engineer
Stone
Mar 2019 - Aug 2022 (3 years 5 months)
Developed and maintained high-volume data pipelines for Pix transaction processing and reconciliation, implementing key cross-referencing with Receita Federal databases and reducing reconciliation time by 40%.
Developed and maintained high-volume data pipelines for Pix transaction processing and reconciliation (millions of events/day).
Implemented Pix key cross-referencing with Receita Federal databases and internal antifraud systems.
Optimized queries and data modeling in PostgreSQL and Cassandra, reducing reconciliation time by 40%.
Contributed to the evolution of event-driven architecture (Kafka) for
Education
Degrees, certifications, and relevant coursework
Descomplica Faculdade Digital
Technology Degree / Associate Degree in Database Technology, Database Technology
Focused on database systems, data engineering and backend development, with practical application in AI-powered software systems.
Coursework and independent engineering projects cover relational data modeling, SQL, database architecture, Python, data pipelines, REST APIs and software development.
Alongside the degree, I build production-oriented projects involving PostgreSQL, FastAPI, Docker, LL
Availability
Location
Authorized to work in
Portfolio
github.com/devviniciusfmk-sysSalary expectations
Job categories
Skills
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