Mark
From Brazil (UTC-4)
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offers now 🔥Mark – Python, React, Next.js
Mark is a Senior Full-Stack Engineer with 8 years of experience, specializing in Python and React with deep hands-on expertise in AI/LLM systems. He's currently building production multi-agent educational platforms using LangChain, LangGraph, WebRTC, and OpenAI — owning everything from architecture to cloud deployment on AWS and GCP. Mark doesn't just implement features; he connects technical choices to product outcomes, designs infrastructure from scratch, and ships without close supervision — a strong fit for AI-first startup teams that need engineers who take real ownership.
8 years of commercial experience in
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Let’s get started today!Experience Highlights
Senior Software / AI Engineer
Speech-to-speech conversational learning tool (LTI) embedded in an LMS, built for AI-driven educational interactions. The platform supports multi-agent Dialogue flows, real-time voice and text sessions over WebRTC, document-aware tutoring with in-session RAG, and AI-generated Key Moments for post-session review. Deployed on AWS and GCP with full accessibility (ARIA/WCAG) compliance.
- Architected multi-agent AI systems using LangChain, LangGraph, and OpenAI — enabling real-time user-to-agent voice and text interactions via WebRTC with supervisor/worker agent patterns
- Replaced Whisper-based transcription with a custom decoupled layer that preserved accuracy when agents were interrupted; added timestamp-based message sorting across LTI and LMS sessions
- Implemented in-memory vector stores with OpenAI Embeddings and pgvector for near-zero-latency real-time RAG over session-bound, multi-source documents
- Built the Dialogue system — a multi-step, context-carrying multi-agent framework with shared conversation history, a sequence builder for assignment types, and AI-generated Key Moments for post-session review
- Instrumented LLM pipelines with Langfuse for end-to-end tracing, latency profiling, and token usage optimization across multi-agent production flows
- Deployed AI-powered services end-to-end (Python/FastAPI, Go/GORM, Next.js) on AWS and GCP, from architecture through production monitoring
Full-Stack Engineer
Personal finance management app for tracking expenses, income, and financial goals, with interactive dashboards and data visualizations. Full-stack open source project with production-grade security architecture.
- Built a full-stack finance tracker with a Next.js 15 / React 19 frontend and NestJS REST API backend backed by PostgreSQL
- Implemented interactive charts and expense visualizations using Chart.js
- Set up JWT authentication with CSRF double-submit cookie protection, Helmet headers, rate throttling, and input sanitization
- Containerized the full application with Docker Compose for reproducible local and deployment environments
- Maintained 215+ commits with branch-based workflow, PR reviews, and documented architecture
Software Engineer
Energy management software for a transformer monitoring system (SMT) at one of the world's largest power plants. The platform tracked real-time sensor data from high-voltage transformers, with strict zero-downtime and regulated testing requirements.
- Refactored an IoT anomaly detection system with AI-driven predictive analysis, improving fault detection accuracy for high-voltage transformer monitoring
- Built serverless and microservices architectures on AWS (Lambda, DynamoDB, S3, EventBridge) processing real-time sensor data streams via Kafka
- Developed real-time data visualization dashboards for the Energy Management sector using Next.js and D3.js
- Optimized PostgreSQL queries and Redis caching layer, reducing system latency by 13%
Software Engineer
Internal tooling team focused on Node.js ecosystem modernization and CI/CD infrastructure. Worked on migrating JavaScript codebases to TypeScript and improving developer tooling used by tens of thousands of engineers daily.
- Wrote unit and integration tests for an internal CI/CD system on the Node.js tooling team, achieving 95% test coverage
- Implemented a Redis caching layer for session tokens in a legacy microservice, reducing average auth latency by 100ms
- Migrated legacy JavaScript utilities to TypeScript and improved CLI tooling serving 20K+ daily users