Principal Software Engineer | AI Specialist | Cloud Infrastructure & AWS Expert

Build with rigor.
Ship what lasts.

Full-Stack TypeScript developer: Node, Angular, React, and React Native. AWS infrastructure, AI-Driven apps, Spec-Driven Development, and TDD.

6+ Years building
3 Trilingual
5 Companies & startups
~/joaopster · zsh
git clone joaopster --depth=6y
Cloning into 'who-i-am'…
remote: 6 years · 5 companies, done.
Resolving identity: 100%
cat strengths.json
{
  "frontend""Angular · React · RN",
  "backend""Node · Lambda · AWS",
  "ai""spec-driven · anti-vibe",
  "motto""rigor over vibes"
}
uptime
up 11,000+ hrs · load avg: shipping

About me

Curious by birth,
engineer by trade.

I'm João, son of a single mom, and I grew up more inside the computer than outside, hooked on logic, strategy, and business from early on. At 11 came the ADHD and giftedness diagnosis, and it took me a while to understand why I thought differently from everyone else; for a while it left me feeling alone, until it clicked that it was exactly what made me unique. I've never accepted anything just because, and it's that stubbornness that drives my urge to pry things open and see how they really work. I married young, because waiting never sat well with me, and today I juggle code, company, and family all at once, as co-founder of a US real estate startup.

Architecture, engineering & infrastructure

I build complete systems from the absolute ground up to production: specification, prototyping, architecture, development, DevOps, infrastructure, and deployment.

See my specialties →

Anti-vibe-coding AI development

I use AI as a tool, not a crutch. I work with spec-driven development, agentic workflows, skills, rules, hooks, and plenty of documentation and context.

See my toolkit →

My specialties

Cloud Infrastructure on AWS

  • Networking and connectivity (VPC, subnets, security groups, NAT, VPC endpoints)
  • Security, IAM and least-privilege permissions (Cognito, KMS, Secrets Manager)
  • Elastic, event-driven compute (ECS Fargate, Lambda, auto-scaling)
  • Asynchronous messaging and integration (SQS, SNS, EventBridge)
  • APIs and edge delivery (API Gateway, CloudFront, Route 53)
  • Data and persistence (RDS PostgreSQL, S3, ElastiCache/Redis)
  • IaC and CI/CD (AWS CDK in TypeScript, CodePipeline, CodeBuild)
  • Observability, logs, alarms and distributed tracing (CloudWatch, X-Ray)

Software Engineering & Architecture

  • Architecture driven by trade-offs (modular monolith, microservices, event-driven, hybrid)
  • DDD, Clean and Hexagonal Architecture (domain boundaries, ports & adapters, dependency inversion)
  • Engineering principles and patterns (SOLID, CUPID, GRASP, GoF, EIP)
  • Web frontend architecture (Angular and React)
  • Cross-platform mobile (React Native)
  • Typed, scalable backends (NestJS, Node.js, TypeScript)
  • API design and resilient integration (versioned REST, real-time/WebSocket, async messaging, idempotency)
  • Quality by construction (automated testing, type-safety, code review)

AI-Driven Apps

  • Intelligent document processing / IDP (invoices, contracts and emails with Gemini multimodal and Cloud Vision OCR)
  • End-to-end multimodal AI (text, image, PDF, audio and video, including audio/video transcription)
  • Content generation (text, audio and image: summaries, replies, voice and image synthesis)
  • Semantic search, RAG and grounding (vector embeddings, similarity and context-grounded decisions)
  • Classification, routing and entity resolution (actionable triage and entity disambiguation)
  • Prompt engineering and orchestration (system prompts, few-shot, LangChain, multi-step pipelines)
  • Reliable structured output (typed JSON, fallback parsing, per-field confidence scoring)
  • Determinism, guardrails and cost (seed/temperature for reproducibility, safety settings, model selection flash/pro)
See more specialties

Technical Leadership

  • Technical vision and architecture ownership (end-to-end decisions across AI, frontend, backend and infra)
  • MVP to production delivery (scope, risk and scale management without blocking the team)
  • Quality and code-review culture (coding standards, testing and review as part of the design)
  • Security as culture, not a checklist (security-first, authentication, encryption, threat review)
  • Mentoring and leveling up the team (knowledge sharing, pairing, living documentation)
  • Trade-off communication and alignment (translating business into technical decisions, influence without authority)
  • Operational ownership (observability, incident response, production reliability)
  • Technical debt and evolutionary architecture (continuous refactoring, safe migrations, schema-drift defense)

Systems Integration & Automation

  • External system integrations (DoorLoop, UniFi Access, email and payment gateways)
  • Event-driven architecture (SQS, EventBridge, async workers)
  • Secure webhooks (signature validation, event-source verification)
  • Scheduled jobs and automation (EventBridge Scheduler, cron/rate lambdas)
  • Resilient synchronization (idempotency, replay-safe, state reconciliation)
  • Email ingestion and processing (mailbox sync, parsing, automatic categorization)
  • Serverless orchestration (Lambda chaining, DLQ, retries)
  • Multichannel notifications (email, push, domain events)

Cyber Security

  • Robust authentication (Cognito, JWT with audience validation, JTI revocation)
  • Authorization and RBAC (roles, guards, privilege-escalation and IDOR prevention)
  • Threat modeling and security review (CRITICAL/HIGH/MEDIUM severity, OWASP mindset)
  • API protection (rate limiting, anti-brute-force, webhook anti-spoofing)
  • Safe concurrency (race conditions, idempotency, integrity constraints)
  • Least privilege (scoped IAM policies, event-source validation)
  • Sensitive data protection (masking, encryption, secrets management)
  • Incident response (session/token revocation, post-downgrade invalidation, audit trail)

Experience

six years
building.

From freelance to co-founder, hands on the code the whole way, through marketing tech, media, and now PropTech.

Co-founder & Developer

2025 - Present

Confidencial · PropTech United States · Remote

I co-found and build an AI platform for the US real-estate market, with AI at the core of the product and present in every feature. Every line of the code is mine.

While we're in our time-to-market phase, I can't go into product details publicly yet.

AI-drivenSpec-driven devTypeScriptScale

Senior Software Development Engineer

2025

adMixt United States · Remote

Senior Full-Stack Developer specialized in modernizing legacy systems through innovative architectures and from-scratch development.

I develop modern, modular solutions using pure Vanilla JavaScript, creating complete features from the ground up without external dependencies and seamlessly integrating them into 20+ year legacy PHP environments. My expertise lies in building bridges between contemporary technologies and established systems, implementing scalable architectures that respect existing environment limitations.

I transform complex technical challenges into innovation opportunities, developing reusable components, dynamic interfaces, and advanced functionalities that elevate user experience without compromising core system stability. I apply modern software engineering principles to create clean, testable, and maintainable code within legacy ecosystems.

Key Technologies & Expertise: JavaScript Vanilla, Modern Web Architecture, Legacy System Modernization, Component-Based Development, Custom Framework Creation, PHP Integration, Database Optimization, Code Refactoring, Progressive Enhancement

Vanilla JSLegacy modernizationPHPAWS

Principal Software Architect & AI Engineer

2024 - 2025

Howhow São Paulo · Hybrid

As LT at Howhow, I lead a dedicated team of technology experts focused on innovating in the influencer marketing sector. Our mission is to develop a revolutionary platform that effectively connects brands with influencers, supported by advanced technologies such as AI, NLP and data analysis. This commitment to innovation allows us to offer solutions that not only meet but exceed our clients' expectations, delivering personalized and high-impact results.

Biggest challenge:
The biggest challenge was to develop a multi-user platform with several levels of access, capable of managing complex marketing campaigns with several influencers simultaneously, involving several stages such as accepting proposals, signing contracts, sending and approving content, reviewing and much more. This complex system required a robust and flexible architecture, as well as an intuitive interface that would allow users to easily navigate these multifaceted processes without compromising efficiency or security.

Our gain:
Overcoming this challenge brought significant benefits to Howhow's clients. With our advanced platform, brands can now manage influencer marketing campaigns more efficiently, monitoring each stage of the process in real time and ensuring compliance and content quality. This has resulted in significant campaign optimization, more effective influencer marketing and a better return on investment. The ability to manage several campaigns and influencers simultaneously, with different levels of access and control over the process.

By delivering the MVP of the platform we can drive it to become a Serie A

AI / NLPArchitectureNode.jsFull-stack

Lead Developer

2023 - 2025

Artweb · João Pster Brazil · Remote

(This is a fixed-term project for a client of my company)

Position: Technical Leader
Team: 2 Designers and 6 Developers
Technologies: React, React Native, Angular, Flutter, GCP, Firebase, Generative AI

Summary:
As Technical Lead at Artweb, I led a highly talented team of 2 designers and 6 developers in the creation and integration of 5 innovative applications, encompassing 2 applications for television, 2 for web and 1 for mobile devices, all aimed at enriching the Artweb system, similar to Netflix, but focused on the exhibition of works of art. Over the course of 1 year and 4 months, our self-managed team produced more than 200,000 lines of code, adopting agile methodologies and tools such as Git Flow, Jira and BitBucket, and implementing a range of advanced technologies that included React, React Native, Angular, Flutter, Google Cloud Platform (GCP), Firebase and Generative Artificial Intelligence.

Biggest Challenge:
The main challenge faced was to achieve fluid integration between the various applications and technologies, ensuring a uniform, high-quality user experience across different devices, while keeping the platform scalable to support the expectation of over 500,000 users already in the first year. This challenge required an innovative and collaborative approach to overcome the technical complexities and ensure interoperability between the different solutions.

Customer Gain:
Overcoming this challenge not only strengthened Artweb's technological infrastructure, but also redefined the way the public interacts with digital art, providing unprecedented access to high-quality artworks through an intuitive interface. The project raised the bar for the digital presentation of art, increasing accessibility and artistic appreciation, resulting in a platform that not only met but exceeded the client's expectations in terms of user engagement and reach, establishing a new paradigm for the digital cultural experience.

ReactReact NativeAngularFlutterGCP

Technology Teacher

2021 - 2024

Independent Brazil · Remote

Technology teacher teaching React, React Native, Angular, Node, Express, Nest, GCP, AWS, Azure and several other technologies to +100 students throughout this period.

ReactNodeNestJSCloud

Founder, Tech Provider & Technical Lead

2023 - 2024

João Pster Brazil · Remote

As a Tech Provider at João Pster's company, I lead several teams of highly qualified technology professionals (I also act as a programmer and teacher) on various projects, committed to driving our clients' success.

I have been active in all the projects below as Technical Lead and Developer, using my own Hands-On leadership methodology.

We specialize in software development, upgrading and enhancing systems and applications, IT outsourcing and technology consulting.

Graduates of Trybe, the largest programming school in Brazil, our professionals not only have exceptional technical skills, but are also experts in soft skills such as teamwork, leadership and time management. At João Pster, we pride ourselves on offering personalized and tailor-made solutions, adapted to the specific needs of each client, guaranteeing a significant impact on their business.

Tech leadConsultingHands-onTeam building

CTO (Tech Provider)

2023 - 2024

Howhow · João Pster São Paulo · Hybrid

As CTO of Howhow, I have the privilege of leading a team of technology experts who are fully committed to making a difference for our clients. We are at the forefront of digital innovation, with a focus on building a revolutionary influencer marketing platform that connects brands to influencers efficiently and effectively.

Our work is powered by cutting-edge technologies, including artificial intelligence (AI), natural language processing (NLP), and advanced data analytics. These capabilities allow us to create high-quality solutions that go beyond our clients' expectations.

In every project we undertake, our team works tirelessly to develop customized solutions designed to meet each client's unique needs. Our goal is always to generate a significant and lasting impact on your business operations.

At Howhow, we pride ourselves on our ability to innovate and adapt. We are always looking for new ways to improve and extend our reach in order to continue to provide the best solutions for our clients.

CTOAI / NLPLeadership

Senior Front-End Developer

2023 - 2024

AfterSale Brazil · Remote

(This is a fixed-term project)

Position: Senior Front-End Developer
Team: Working in a self-managed team
Technologies: React

Summary:
As a Senior Front-End Developer at AfterSale, I was tasked with creating dynamic and innovative front-end solutions to enhance the company's reverse logistics platform. Working in a self-managed team, I made extensive use of React technology to develop interfaces that not only improved the user experience, but also the overall efficiency of the platform, contributing significantly to the optimization of reverse logistics processes.

Biggest Challenge:
The most significant challenge I faced was implementing a dynamic and highly intuitive user interface at a crucial stage of the reverse logistics process, within a pre-existing and complex system. The difficulty lay in the need to integrate modern, agile front-end solutions into the legacy code, while keeping the system's stability and performance intact. This challenge required not only a technical mastery of front-end technologies, but also a capacity for innovation and creativity in interface design, as well as a deep understanding of the limitations and characteristics of the legacy system.

Customer Gain:
Successfully overcoming this challenge resulted in a substantial improvement in the user experience within the reverse logistics platform, making the process more intuitive, efficient and less prone to errors. This not only increased end-user satisfaction, but also optimized AfterSale's internal operations, leading to more effective management of reverse logistics processes. The implementation of these dynamic, user-friendly interfaces has translated into tangible operational gains for the company, reinforcing its position in the market and highlighting the importance of innovative front-end solutions for the continuous improvement of reverse logistics services.

ReactFront-endLegacy

Mid Front-End Developer

2023

Digital Republic São Paulo · On-site

Position: Mid Front-End.
Team: Collaboration with multidisciplinary and self-managed teams
Technologies: Next.js, Angular

Summary:
At Digital Republic, I worked as a Technology Consultant and Senior Front-End Developer, getting involved in innovative projects focusing on emerging technologies such as Next.js and Angular. My experience included collaborations with renowned entities such as Fundação Bradesco and RG/A, where I played a crucial role in developing customized, efficient and high-impact technological solutions. Working alongside multidisciplinary teams, I employed a combination of technical and analytical skills to ensure the delivery of quality projects in line with client expectations and needs.

Biggest Challenge:
The most significant challenge was the development of a highly dynamic and complex website for RG/A, characterized by an innovative layout, unique animations and an extensive structure that included a blog. The project required both the website and the blog to be modifiable via a no-code platform, which provided the necessary page structure in JSON format, with each blog post requiring a personalized page defined by a distinct JSON. To overcome these challenges, I adopted a strategic approach, segmenting the project into modular components that I called "Bricks", and developed each one following the Atomic Design methodology. This strategy allowed for clear documentation and efficient implementation, resulting in the successful delivery of the project in half the planned time.

Next.jsAngularAtomic Design

Mid Full-Stack Developer

2022 - 2023

Verzel Brazil · Remote

Position: Mid Front-End
Team: Collaboration with multidisciplinary and self-managed teams
Technologies: Angular, React, Node

Summary:
While at Verzel, I held the roles of Technology Consultant and Senior Front-End Developer, getting involved in challenging projects that utilized Angular and React. One of my notable contributions was the development of an advanced chatbot for Mutant, aimed at significantly improving communication and the user experience. I worked closely with multidisciplinary teams, applying a mix of technical and analytical skills to ensure that the solutions delivered were perfectly in line with the clients' needs and objectives, excelling at creating innovative solutions that boosted the functionality and efficiency of projects.

Biggest Challenge:
Developing the advanced chatbot represented a significant challenge, mainly due to the need to integrate it seamlessly with the client's existing systems, while ensuring a fluid and intuitive user experience. The project required an in-depth understanding of the capabilities of Angular and React, as well as a creative approach to implementing AI functionalities that would enable the chatbot to understand and respond to users' needs effectively.

AngularReactNodeChatbot

Freelance Web Developer

2020 - 2022

Independent Brazil

Working on +50 small projects that are summarized here, I played a key role in the development and leadership of multidisciplinary teams in various projects of varying sizes and scopes. With extensive experience in technologies such as React, Angular, Vue, React Native, Express, Node, Django, WordPress and even Wix, I was responsible for creating interfaces and UI/UX, applying my knowledge of product design, user experience and application architecture.

Throughout my career, I have interviewed, assessed and hired exceptional talent for our teams, always adopting agile methodologies such as SCRUM/KANBAN, together with tools such as Jira and Slack, to ensure successful and efficient projects.

I developed important skills during this period, including negotiation, teamwork, leadership, communication, assertiveness and providing constructive feedback. In addition to my work at Pster, I've freelanced and provided services to various marketing agencies, such as Really, and worked on confidential projects, such as Detran de SC.

Although I'm presenting just a few samples of my work, my experience covers a wide range of projects of different scales and challenges, always seeking to deliver innovative, high-quality solutions for our clients.

ReactAngularVueUI/UX

.NET Developer

2019 - 2020

Self-employed Remote

I've developed mods in .NET with C# for various games based on Harmony X technology, I had a store to sell plugins and mods called CastCodes, I've worked in international teams and managed virtualized servers in AWS, GPC and Azure.

.NETC#HarmonyXGame dev

In Frontend, Backend, Infrastructure and AI Development

I already have over 11,000 hours developing in this stack.

Frontend

Interfaces built with care.

  • Design & prototyping Strong at design and prototyping in Figma; in code, SCSS and whatever it takes to reinforce every visual detail.
  • React, Angular & React Native React, Angular, and React Native on the same mental model. Web and mobile without switching gears.
  • SEO & Web Vitals Technical SEO and Core Web Vitals wired in from the start, not patched in at launch.

Back & Infra

Built to scale, run on AWS.

  • AWS specialist ECS, Lambda, networking, IAM, CloudFront. I set up the whole platform from scratch, nothing outsourced.
  • Node.js & Lambda NestJS or Lambda, depending on the problem. Modular monolith when it fits, microservices when it doesn't.
  • Scale, observability & security Hold up under load, ship with logs, metrics, and distributed tracing from day one. Security isn't an afterthought.
How I ship

Ship products that work, and keep working.

Good software rarely comes from clever abstractions. It comes from the dull work of clear boundaries, typed contracts, and tests that run. I build for whoever touches the code two years from now, not for today's excitement.

See what I've built →
Production deploy
TypeScript check Passed
Unit tests (47) Passed
Documentation 13 docs
Build complete 1.2s
Deployed Live
https://joaopster.com
The writing

Write to think. Publish to share.

Writing is how I find out what I actually understand. I publish long pieces on tooling, architecture decisions, and the tradeoffs that don't fit in a tweet. If one post saves you an afternoon of debugging, that's enough.

Read the blog →
Coding time

Code every day. Tracked since January 2026.

Hours measured, not guessed. WakaTime logs all of it on its own: languages, projects, editors. The history starts in January 2026, when I began tracking.

Before that I'd been coding since 2020, just not measuring. At 8h a weekday, that's roughly 12,480 hours + 893h = ~13,373h.

View WakaTime →
WakaTime
@JoaoPster
--- Total coded
--- Daily avg

My toolkit

What I actually use.

Broken down by category: languages, frameworks, and the AI tools that changed how I work.

Languages & Technologies
TS TypeScript
JS JavaScript
No Node.js
Py Python
AWS AWS
PG PostgreSQL
Rd Redis
Dk Docker
Frameworks
Ng Angular
Rc React
RN React Native
Ne NestJS
Exp Expo
As Astro
AI Tools
CC Claude Code
OMC oh-my-claudecode
Cur Cursor
Exa Exa
Sr Serena
C7 Context7
Mem Memory
Qd Qdrant
Gph Graphify
Ln Linear
Sn Sentry

"The best tech stack is the one your team can ship with confidently and maintain without dread."

João Pster

From solo tools to production systems.

6+ Years building

Building software since 2020.

5 Companies & startups

From marketing tech to media and PropTech.

3 Trilingual

Portuguese, English, and Spanish.

Want to build
something together?

I'm always happy to talk architecture, AI engineering, or what you're building, whether it's a project, a role, or just a good technical problem.