Denis Magalhães
Skills & Technologies
Stack shaped by AI education products, LMS integrations, and reliable full-stack delivery
About Me
Founding Engineer for AI Education Products
I build end-to-end systems that remove friction for teachers and turn complex AI workflows into reliable product surfaces
MongoDB 2024 - I love technologies that solve real business problems
At CoGrader, I build the AI grading and feedback platform that helps teachers grade a class set of essays in minutes instead of a weekend. I own features end to end: grading pipelines, backend services, the web app, the browser extension, the data layer, and the infrastructure under all of it.
How I Work
End-to-end ownership is literal for me. A single feature can take me through the design system, React app, shared components, API, queue workers, AI engine, Firestore, and Terraform that deploys it.
I fix causes, not symptoms. Whether the issue is an engine-selection bug, a rollout mechanism that belongs behind a runtime flag, or an error state that should not be logged as an outage, I trace the mechanism until the family of cases is actually solved.
I treat observability, teacher-facing copy, and AI tooling as product surfaces. PostHog, Axiom, Claude Code, MCP, and live system context are part of how I ship faster without turning reliability into guesswork.
Solution Arsenal
Each integration below solved a specific business problem — from automating processes to scaling operations globally:
Intelligence & Automation
eliminating manual work while keeping AI behavior measurable
Global Monetization
processing millions in secure transactions
Scale Reach
connecting businesses with millions of users
Critical Performance
keeping asynchronous workflows fast and reliable
Scalable Infrastructure
from MVP to production scale
Total Visibility
separating product blockers from genuine failures
Proactive Protection
securing data and reputation
Multiplying Impact
I believe knowledge not shared is knowledge wasted. That's why I transformed the habit of learning into a commitment to teach. Each workshop is a chance to plant seeds of transformation in other careers.
Frontend & Backend Workshop - Beetech
In-person workshop teaching full-stack development to the tech community at Beetech (https://beetech.global/)
Git & Version Control Workshop - SENAI
Training on version control and best practices with Git at SENAI
Mobile Development Workshop - Itaú
Internal event at Itaú focused on mobile development and networking among developers
Flutter + AdonisJS - FATEC Zona Sul
Presentation on Flutter integrated with AdonisJS, market trends, and emerging technologies for students (03/04/2025)
I did this for them today, and I hope they can do the same for others in the future. It's rewarding to share knowledge and see people growing professionally.
My greatest pride isn't the lines of code I wrote — it's the companies that scaled, the teams that led with autonomy, and the impossible problems that became success stories. Projects that started as sketches on whiteboards now serve millions of users globally.
I'm driven by challenges that seem too big, deadlines that seem too tight, and problems no one has solved yet. My mindset is simple: if there's a better way, I'll find it. If there isn't, I'll create it.
If you have a complex problem that needs someone who thinks beyond the obvious, let's talk. I won't promise it'll be easy — but I will promise it'll get solved.
Professional Experience
Building solutions that scale and generate real impact
Founding AI Full-Stack Engineer
CoGrader
Remote
As a founding engineer, I build CoGrader's AI grading and feedback platform for K-12 teachers. The product helps teachers grade a class set of essays in minutes instead of a weekend, powered by Gemini, OpenAI, and Anthropic on Google Cloud.
Key Highlights:
- ▸Built the browser extension that puts CoGrader directly inside Canvas, Blackboard, Schoology, Brightspace, Microsoft Teams for Education, and Google Classroom
- ▸Removed the LMS partnership bottleneck by turning months-long integrations into an install-and-use teacher workflow
- ▸Own grading and feedback pipelines, prompts, tasks, workflows, evals, document ingestion, backend services, web app, data layer, and infrastructure
- ▸Work across React/Vite, Mantine, Plasmo, Node.js/Express, BullMQ workers, Firestore, Redis, Terraform, Docker, and GitHub Actions
- ▸Treat observability as product: PostHog, Axiom, cost tracking, feature flags, and clearer error taxonomy for real teacher-facing blockers
- ▸Built AI-assisted engineering conventions with Claude Code, MCP, and live-system integrations for PostHog, Axiom, Slack, Azure, and GitHub
Tech Stack:
Backend & Infrastructure:
Frontend:
AI & Integrations:
Infrastructure:
CTO & Tech Lead
Fintech & iGaming (NDA)
Jun 2024 - Before CoGrader
Remote
Led complete technical conception, development, and delivery of high-performance platforms in Fintech and iGaming before CoGrader.
- Complete architecture of scalable platforms from scratch
- Management of multidisciplinary technical teams (DevOps, Web Frontend, Mobile)
- Implementation of recurring payment and cryptocurrency solutions
- Integration with third-party APIs for security and compliance
Tech Lead & Senior Software Engineer
GO-K Digital (Grafeno Digital)
Mar 2023 - Jun 2024
Remote
Led the Credit Emission project, transforming a complex manual process into an automated platform that reduced analysis time by 70% and expanded the company's operational capacity.
- Architected scalable APIs with NestJS processing thousands of daily requests with 99.9% uptime
- Implemented intelligent caching with Redis reducing query latency by 85%
- Automated deploys with CI/CD eliminating 95% of human errors in production
- Led team through structured IDPs, accelerating promotions and talent retention
Tech Lead - Authentication & Permissions Squad
Itaú BBA
Jul 2022 - Feb 2023
São Paulo
Led critical squad responsible for security and access control of millions of daily corporate transactions in the new Bankline, ensuring compliance and frictionless experience.
- Architected corporate authentication solution with Auth0 supporting 50k+ simultaneous users
- Achieved 90% test coverage (TDD) ensuring zero critical vulnerabilities in production
- Implemented end-to-end encryption with Charon protecting billions in transactions
- Delivered accessible system (WCAG 2.1) expanding user base by 15%
FIC Engineer
Trustly
Sep 2021 - Jul 2022
Remote
Solved the technical challenge of integrating payment gateway with American banks without public APIs, creating intelligent scraping solutions that process millions in monthly transactions.
- Developed robust integrations with 15+ North American banks via resilient web scraping
- Implemented multi-cloud rotation (AWS, GCP, Azure) maintaining 99.5% availability
- Created change detection system preventing breaks before user impact
- Stack: Java, PostgreSQL, Docker, Selenium, Scraping, Multi-Cloud
Software Engineer - Mobile
Itaú Unibanco
Jun 2019 - May 2021
São Paulo
Developed critical WebViews for Itaú mobile apps (Android/iOS) used by millions of customers, ensuring performance and consistent experience across multiple platforms.
- Created reusable Angular components reducing development time by 40%
- Optimized WebView performance improving load time by 60%
- Automated deploys with AWS S3 + CodePipeline accelerating releases by 3x
- Stack: Angular, TypeScript, AWS S3, CodePipeline, Java, Docker, Jenkins
Technology Consultant Senior
Sthorm
Mar 2020 - Mar 2021
Remote
Full-stack consultant building ViralCure, a telemedicine platform that connected thousands of patients with healthcare professionals during the pandemic.
- Developed complete platform from scratch reaching MVP in 3 months
- Architected scalable solution supporting 10x traffic spikes
- Implemented real-time scheduling system with multi-device synchronization
- Stack: Angular, NestJS, PostgreSQL, Docker, Scrum, Trello
Software Engineer
Accenture
Apr 2018 - Jun 2019
São Paulo
Worked on Porto Seguro project developing highly complex corporate portals that optimized internal processes and improved experience for thousands of brokers.
- Developed critical features in Angular with 99% end-user satisfaction
- Integrated legacy systems with modern APIs reducing process time by 50%
- Stack: Angular, Java, Spring, REST APIs
Software Engineer
QueroQuitar
Apr 2016 - Jan 2017
São Paulo
Developed critical integrations with multiple credit providers, automating debt negotiations and facilitating agreements that impacted thousands of people.
- Integrated 20+ providers via REST and SOAP consolidating data from multiple sources
- Implemented TDD ensuring 0 regressions in critical financial flows
- Optimized MongoDB queries reducing response time by 70%
- Stack: Angular, Laravel, Lumen, MongoDB, MySQL, Docker, TDD
Software Engineer Intern
Ingresse
Dec 2014 - Feb 2015
São Paulo
Internship focused on backend development for ticketing platform, learning fundamentals of scalable APIs and high-performance architecture.
- Developed REST APIs in PHP/Symfony processing thousands of daily transactions
- Learned best practices for scalable architecture and production performance
- Stack: PHP, Symfony, Nginx, REST APIs
Intern
Porto Seguro
Nov 2013 - Oct 2014
São Paulo
First professional internship where I learned software development fundamentals, teamwork, and agile methodologies in a corporate environment.
Featured Projects
Solutions that generated real impact and scaled businesses
Awards & Recognition
Innovation recognized and nationally awarded
Adapta Summit 2025
1st Place - $18,000 USD
Winner of the event's top prize with innovative Out-of-Home media solution powered by Artificial Intelligence and Computer Vision
Impacto: Revolutionary solution that transforms urban advertising through cutting-edge technology
Adapta Hackathon 2025
Awarded - $7,200 USD
Awarded for developing pioneering platform for outdoor media analysis and optimization using AI
Impacto: Rapid prototyping and validation of innovative concept in 48 hours
Adapta Mídia
Revolutionizing Out-of-Home Advertising with Artificial Intelligence
Innovative platform that uses Computer Vision and AI to analyze, optimize, and maximize the impact of outdoor media campaigns in real-time.
Award ceremony moment at Adapta Summit 2025
System Architecture
A look under the hood of the products I've built — select an architecture to explore how each one is wired end to end.
Cloud-native computer-vision platform on Google Cloud
Client applications
An Android app built with Flutter runs YOLO (Ultralytics) for on-device computer vision, while the admin panel is a React web app deployed on Vercel. Both consume the same backend API.
Edge & delivery
Cloudflare sits in front of the platform as the edge layer — handling DNS, CDN caching, TLS, and protection — and routes every client request to the backend API.
Backend on Google Cloud
The API runs on Google Cloud Run (serverless containers, auto-scaling). Firebase handles auth and realtime needs, MongoDB is the primary database, and Redis powers caching and the job queue.
AI & storage
Google Vertex AI provides the managed machine-learning layer for advertising analysis, and Google Cloud Storage holds media assets, uploads, and processed outputs.
Talks & Presentations
Sharing knowledge and experiences with the tech community
ChatGPT Integrated with WhatsApp
Technical presentation on integrating ChatGPT with WhatsApp using Facebook's official API and Nest.js
Tópicos Abordados:
Tech Stack:
Node.js, Nest.js, OpenAI API, WhatsApp Business API, TypeScript
Let's Build Something Extraordinary Together
Get in touch to discuss your next project or opportunity
I'm always open to new challenges, strategic partnerships, and opportunities to create impact through technology.
Building the future, one line of code at a time
© 2025 Denis Magalhães. All rights reserved.