status:open to hearing about interesting opportunities

I build banking and enterprise interfaces — and keep them fast after the product gets complicated.

Lead Frontend Engineer at Happen Bank (formerly LendingClub). Twelve years across mobile banking at Sicredi, enterprise platforms at SAP and messaging at Zenvia — mostly React, TypeScript and React Native, mostly on the parts users actually feel: load time, focus order, layout stability.

View selected work Get in touch
role
Lead Frontend Engineer
at
Happen Bank — since 2021
before
SAP · Sicredi · Zenvia
based
Novo Hamburgo, BR (UTC−3)

01what i do

Engineering that shows up in the product

I focus where frontend work is most visible to users and most valuable to the business — speed, systems, and reliability across platforms.

  1. Performance & Core Web Vitals

    Profiling, code-splitting and rendering strategy to keep interfaces fast under real-world load and constraints.

  2. Design systems & UI architecture

    Reusable, accessible component libraries that scale across teams and keep products visually consistent.

  3. Cross-platform apps

    Web, React Native and Flutter — one product language across every screen your users reach.

  4. Full-stack integration

    Wiring frontends to Node.js, Django and Java services with clean contracts and resilient data flow.

02selected work

Products I've helped build

Fintech, editorial and commerce — production work alongside a few side projects I maintain.

  1. Happen Bank (formerly LendingClub)

    Fintech · Web & Mobile

    Led frontend for a banking product serving millions of users. Shipped new features, drove page-speed and accessibility gains, and integrated with Django, Node.js and Java services.

    stack:React · TypeScript · Performance · A11y
    2021 — Present

  2. Audible Blog

    Editorial · Next.js

    Built the Audible (Amazon) blog with Next.js, improving SEO and engagement through server rendering and a reusable, scalable component system.

    stack:Next.js · SSR · SEO
    2021

  3. Sicredi Mobi

    Mobile Banking

    Improved UX and security for a hybrid mobile banking app, optimizing assets and API requests to cut load times.

    stack:Hybrid · Kony · Security
    2017 — 2018

  4. Porto Pão App

    Commerce · Ionic

    Customer ordering app integrated directly with a legacy ERP's SQL database. Built end-to-end with Ionic, Node.js and MongoDB.

    stack:Ionic · Node.js · MongoDB
    Side project

  5. yt-assist

    Side project · GenAI

    Web app and browser extension that summarizes any YouTube video with generative AI — paste a link and get the key insights in seconds, no fluff.

    stack:GenAI · Browser Extension · TypeScript
    Personal

  6. PostCraft

    Side project · SaaS

    AI content studio for Instagram: generates on-brand captions, images and hashtags ready to publish — no design skills needed. Built with Next.js, OpenAI and Stripe.

    stack:Next.js · GenAI · Stripe
    Personal

  7. Arbitrader

    Side project · Fintech

    Node.js bot that scans crypto exchanges for price gaps and executes cross-exchange arbitrage opportunities automatically.

    stack:Node.js · Crypto · Automation
    Personal

03career

A decade-plus building for the web

From internships in enterprise backends to leading frontend at banks and global platforms.

Experience

  1. 2021 - present

    Lead Frontend Engineer

    Happen Bank (formerly LendingClub)

    Led the development of the Happen Bank (formerly LendingClub) banking app, serving millions of users with a seamless financial experience. Built new features and optimized performance for the company's website, improving page load speed and accessibility. Integrated the frontend with several backend services (Django, Node.js, Java), ensuring smooth communication across systems. Led a team of developers, providing guidance on best practices, code reviews, and system architecture decisions.

  2. 2021 - 2021

    Lead Frontend Engineer

    HappyFunCorp

    Developed the Audible Blog (Amazon subsidiary) using Next.js, improving SEO and user engagement. Led the development of Kithward Backoffice, collaborating with stakeholders to define project scope, prioritize features, and deliver results on schedule. Designed and implemented reusable UI components, ensuring a consistent and scalable design system.

  3. 2020 - 2021

    Lead Frontend Engineer

    ilegra

    Developed the Thomson Reuters Brazilian Accounting Platform using Angular, streamlining financial data management for enterprises. Led the development of React Native apps for security systems, integrating IoT features for home monitoring and alert systems. Implemented automated testing with Jest, increasing test coverage and reducing regression issues.

  4. 2018 - 2020

    Lead Frontend Engineer

    SAP

    Architected and led the development of frontend solutions for enterprise applications, focusing on performance and scalability. Built PoC solutions utilizing Machine Learning and Big Data to enhance decision-making capabilities. Designed and developed user-friendly interfaces for internal tools using React and Flutter. Managed SCRUM processes, optimizing team efficiency and delivery schedules.

  5. 2017 - 2018

    Senior Software Engineer

    Sicredi

    Developed and maintained Sicredi Mobi, a hybrid mobile banking app, improving user experience and security. Enhanced app performance and reduced load times by optimizing mobile assets and API requests.

  6. 2016 - 2017

    Mobile Developer

    Qintess (formerly Resource IT)

    Built mobile banking applications using Kony Framework, enhancing security and usability. Provided ongoing support and feature updates, improving app stability and performance.

  7. 2015 - 2016

    Mobile Developer

    DBServer

    Developed native Android applications using Java (Android SDK) and hybrid apps with Ionic & MEAN stack. Delivered projects for enterprise clients, including Vivo Meu Negócio, Retool, and DBVitae.

  8. 2014 - 2015

    Mobile Application Developer

    SoftMóvel

    Designed, built, and maintained Android applications for business and logistics. Key projects: SivaPlus, SivaGeo, SivaDelivery, SivaTrade.

  9. 2012 - 2013

    Software Developer Internship

    Dell

    Assisted in developing backend solutions for enterprise applications using PL/SQL. Supported system enhancements for internal business operations.

04how i work

Opinions I hold at work

01

Slow is a bug, not a theme

Nobody opens a ticket saying the app feels heavy — they just stop using it. I'd rather treat a 400ms interaction as a defect with an owner than let it live in a backlog column called "performance".

02

A component's API is a contract

Components are cheap to write and expensive to change. A week spent on the props of one Button beats a year of untangling the thirty places somebody forked it.

03

Accessibility is mostly doing it properly

Real buttons, sane focus order, labels that match what's on screen. Most of it isn't extra work bolted on at the end — it's the same work, done right the first time.

I hear and I forget. I see and I remember. I do and I learn.
— Confucius

05toolbox

Technologies I reach for

Frontend
  • React
  • TypeScript
  • Next.js
  • Angular
  • React Native
  • Flutter
Backend & Data
  • Node.js
  • Django
  • Python
  • Java
  • PostgreSQL
  • MongoDB
Craft & Tooling
  • Design Systems
  • Web Performance
  • Accessibility
  • Testing (Jest, Cypress)
  • Docker
  • CI/CD

06writing

Notes on frontend & tooling

All posts

07let's talk

Have a role or a project in mind?

Always glad to hear about interesting staff and lead frontend opportunities. The fastest way to reach me is email.

brunohaetinger@gmail.com LinkedIn