Open to opportunities

Leonardo Koslowski

@leonardokoslowski

Message

I build scalable financial and SaaS front-end platforms with React and Next.js.

Brazil

Message

What I'm looking for

I'm looking to lead and build high-quality, scalable front-end products, partnering with Product, Design, and Back-end teams while mentoring developers and shaping engineering standards.

At AmFi, I lead front-end development for the financial platform and institutional website, building the core platform in Next.js and integrating Ruby APIs and blockchain services. I also deliver financial dashboards, reporting modules, data visualizations, and a headless WordPress and Next.js architecture.

I've spent more than 17 years evolving from websites and landing pages to technical leadership for mission-critical fintech, e-learning, and SaaS products. Across Kofe, ília digital, HostGator América Latina, and DOT digital group, I've built with React, Vue.js, Next.js, and TypeScript while defining architecture, mentoring developers, and improving performance and scalability.

Experience

Work history, roles, and key accomplishments

Front End Tech Lead

AmFi

Sep 2022 - Jul 2026 (3 years 10 months)

Responsible for front-end development of AmFi's financial platform and the company's institutional website, with technical leadership of the front-end development team.

• Mentored developers through code reviews, architecture decisions, and development best practices.
• Defined coding standards, front-end architecture, and scalable processes to ensure platform quality and evolution.
• Partnered w

HTML5 Claude Code CSS Web3.js Git Sentry React Testing Library Prettier ESLint Next.js Jest Storybook SASS JavaScript TypeScript CI CD Figma

Independent Front-End Consultant

Kofe

Jul 2018 - Jul 2025 (7 years)

Responsible for providing front-end consulting and development services to clients across different industries.

• Built modern web applications with React, Vue.js, Next.js, Nuxt, and JavaScript.
• Worked directly with clients from requirements gathering through solution implementation.
• Contributed to projects ranging from institutional websites to more complex web applications.

HTML5 CSS Vue.Js Prettier Nuxt.Js ESLint Next.js React JavaScript TypeScript

Front-End Specialist

ília digital

Jan 2020 - Aug 2022 (2 years 7 months)

Responsible for developing a corporate card management platform for the Spanish market, focused on expense control and financial operations for businesses.

• Built and maintained the core platform using Vue.js, starting on a team of three front-end developers and later taking full ownership of the front-end as the sole developer in the area.
• Worked with cross-functional teams to deliver scalabl

HTML5 CSS Vue.Js Prettier ESLint React JavaScript

Senior Front-End Developer

HostGator América Latina

Nov 2018 - Dec 2019 (1 year 1 month)

Responsible for developing strategic customer-facing products using React and Redux.

• Built and maintained the Customer Portal, implementing new features and improvements to the self-service experience.
• Built and evolved the Checkout application, focused on performance, usability, and front-end maintainability.
• Worked with cross-functional teams to deliver scalable, high-quality interfaces.

HTML5 CSS Redux React Testing Library Prettier ESLint Jest React JavaScript TypeScript

Front-End Developer

DOT digital group

Dec 2008 - Oct 2018 (9 years 10 months)

Responsible for front-end development at DOT Digital Group for nearly a decade, evolving from building websites and landing pages to leading front-end technical strategy for the company's core distance-learning platform.

• Built landing pages and institutional websites, creating responsive, interactive interfaces for marketing campaigns using jQuery, Drupal, HTML, and CSS.
• Contributed to defini

HTML5 Vue.Js CSS Prettier ESLint jQuery