Rafael da Costa Nunes

Hi, I'm Rafael da Costa Nunes.

Software Engineer • Go, TypeScript, React/Next.js & Vue/Nuxt • AWS & Terraform

About me

Software Engineer focused on architecting and shipping scalable, resilient solutions for web applications, APIs, and enterprise services. I've led high-complexity strategic migrations with strong cost savings and performance gains, and worked on payment systems — Credit Card, Payment Link, Apple Pay, Pix, and Boleto — from design to production.

Focus areas

  • Backend & APIs — Go, TypeScript, Laravel, webhooks, and integrations

  • Cloud & IaC — AWS, Terraform, serverless, and high availability

  • Mentoring & quality — coding standards, reviews, and developer training

Integrated platforms

At Appmax, I was responsible for the App Store's payments API: for nearly 3 years I directly onboarded integrations from major market platforms that use Appmax as their payment gateway.

  • Loja Integrada
  • Yampi
  • Tray
  • Wake
  • Uappi
  • Linx Commerce
  • Olist
  • Jet
  • WX3
  • Irroba
  • Shoppub
  • FacilZap
  • Digital Manager Guru
  • Magento

Experience

  • Software Engineer IV

    Appmax · 2026 — Present

    Leading the unified onboarding initiative across multiple products and teams, with Go backend services integrating biometric identity verification (Unico) and banking APIs (Celcoin).

  • Software Engineer III

    Appmax · 2024 — 2026

    PoC and technical lead on the Cognito → Keycloak migration, with a direct production rollout, 100% success, a seamless zero-downtime migration, and a 99%+ reduction in M2M authentication costs (AWS: ~R$300k/mo → ~R$1k/mo). Technical reference for the App Store, driving architectural decisions and solution standardization. Maintained and evolved the Keycloak infrastructure post-migration and trained 10 engineers in authentication architecture.

  • Software Engineer II

    Appmax · 2023 — 2024

    Built the AppmaxScripts library (JavaScript via CDN), implemented rate limiting and a blocking flow integrated with anti-fraud. PoCs to decouple integrations (Yampi/Nuvemshop) from the monolith into App Store apps.

  • Junior Software Developer / Intern

    Appmax · 2021 — 2023

    Built the Apphook system (granular webhooks), migrated Vue 2 → Vue 3 + Tailwind, developed a component library (raising test coverage from under 20% to over 95%), and created the email signature generator (Vue.js), adopted company-wide (600+ users).

Technologies

Languages · 5

  • GoBackend, APIs, Microservices
  • TypeScriptFrontend, APIs, Libraries
  • JavaScriptFrontend, CDN, Utilities
  • PythonScripts, Automation, Data Science
  • BashShell Scripts, Automation, Linux

Frontend & Backend · 8

  • Vue.jsSPAs, Components, Reactivity
  • Nuxt.jsSSR, SSG, Meta Framework
  • ReactSPAs, Hooks, Components
  • Next.jsSSR, SSG, React Framework
  • PrimeReactUI Kit, Components, Themes
  • LaravelREST APIs, MVC, Eloquent ORM
  • TailwindCSSUtility-first, Design System
  • NestJSNode.js Framework, APIs, Swagger

Testing · 3

  • CypressE2E Testing, Automation, QA
  • VitestUnit Testing, Vite-native, Fast
  • JestUnit Testing, Mocking, Snapshots

Cloud & DevOps · 5

  • AWSLambda, S3, CloudFront, API Gateway
  • TerraformIaC, Automation, Infrastructure
  • DockerContainerization, Deploy
  • KubernetesOrchestration, Scaling, DevOps
  • RabbitMQMessage Broker, Queues, Events

Databases · 5

  • MySQLDatabase, SQL, Relational
  • PostgreSQLDatabase, ACID, JSON
  • MongoDBNoSQL, Documents, Flexible
  • RedisCache, In-memory, Session
  • TypesenseSearch Engine, Real-time, Fast

AI & LLMs · 4

  • OpenAIGPT-5.2, GPT-5.1, GPT-5
  • Google GeminiGemini Pro, Multimodal AI
  • Groqgpt-oss-120b, gpt-oss-20b
  • OllamaLocal LLMs, Self-hosted, Privacy

Messaging & Automation · 2

  • WhatsAppFlows, Templates, Automations
  • SlackBots, Webhooks, Integrations

Portfolio

Products & platform · 13

🏪 App Store

Technical reference

Full marketplace with OAuth2, an integrations API, payments (Apple Pay, Pix, Boleto), and strategic integrations (Yampi, Nuvemshop).

💰 Cognito → Keycloak Migration

Cost savings

Full migration of the M2M authentication system from AWS Cognito to self-hosted Keycloak, delivering a massive reduction in operating costs.

🔧 Apphook System

Advanced webhook system with per-SKU granularity, multiple simultaneous hooks, customizable payloads, and manual resend. A complete overhaul of the notifications system.

📦 AppmaxScripts (CDN)

JavaScript library distributed via CDN for secure checkout, PCI-compliant tokenization, and simplified integration with Appmax payments.

🔐 Lambda + Go Authorizer

AWS Lambda + API Gateway authorizer with Terraform, user management in Cognito, and automatic docs with NestJS + Swagger.

🤝 Yampi & Nuvemshop Integrations

Direct negotiation with CEOs and development of OAuth2, Apple Pay, and Payment Link integrations for hundreds of connected stores.

🧩 Component Library

Vue 2 + Bootstrap → Vue 3 + Vuetify + Tailwind migration: standardized components with a design system, automated tests, and developer guidance.

🎯 Multi-Provider AI System (Golang)

Golang integration for AI-driven sales and customer management. Multiple providers (OpenAI, Gemini, Groq) across different contexts and scales, optimizing cost and performance.

🧠 Unified Onboarding (Unico by Client + LLM)

Integration with Unico by Client for unified Max + Appmax onboarding, boosting conversion. Stack: Golang, API Gateway, encryption, RabbitMQ/SQS, and an LLM-powered Intelligence Middleware.

🤖 Sales Recovery (AI)

Evolution of the AI-powered recovery product. Laravel backend for a public API, structuring the AI recovery flow for consumption by platforms and external integrations.

💸 Giftmax (Cashback)

Cashback system with a Laravel backend, managing the full flow (creation, validation, balance, redemptions) and payment integration. Published via public API for multiple platforms.

📊 Satisfaction Survey (NPS)

Satisfaction survey with RabbitMQ and Vue 3, driving a significant increase in the platform's NPS.

📧 Signature Generator

Vue.js system to automate the creation of email signatures, widely adopted across the company and integrated into the onboarding process.

Certifications

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113 certificates from technical courses and programs across 4 institutions — continuous learning, from languages to architecture. A few topics:

PHP / Laravel35JavaScript15Testing & TDD9Go8AWS8HTML & CSS8Node.js6Vue5NestJS4Security4