Hernany Costa

Software consultancy. SaaS platform for a US legal tech company.

• •Led the front-end migration from React 16 to React 18, replacing 10+ libraries with zero downtime and clearing the security risk of a stack the ecosystem no longer supported.
• •Upgraded the back-end from Django 4 to 5.2 through incremental deploys with zero downtime, moving the platform off an end-of-life release and back into security support.
• •Chose and rolled out Rspack in place of Webpack: 3.8x faster builds, 12x faster HMR and a 63% smaller initial JS bundle, shortening the feedback loop for the whole team.
• •Replaced the legacy data table on the system's main screens with an Ant Design implementation, delivering the column resizing, column reordering and row selection users had been asking for while keeping the screens responsive on large datasets.
• •Build features end to end with Django REST Framework, PostgreSQL, Celery and React, covered by pytest and Jest tests.
• •Mentor junior developers through pairing and code review.

Software consultancy. Large telecom company, with over 1 million users.

• •Built the self-service support flow in the mobile app, which applies automated fixes or schedules a technician visit, giving over 1 million subscribers a way to resolve issues without calling support.
• •Delivered features across the web portal and the mobile app, including the invoice screens subscribers use to pay their bills and the satisfaction surveys that fed the support team's quality metrics.
• •Built and maintained reusable, responsive Vue.js components, documented in Storybook and shared across a micro frontend architecture.
• •Worked on the BFF and the microservices in Node and Python that served the front-end applications.
• •Kept delivery quality high with Jest tests and code reviews.

Payments and credit fintech. Freelance work on evenings and weekends, alongside my full-time role.

• •Migrated the self-service kiosk software, running on 50+ points of sale, from an Angular webview to an Electron app with React, removing the knowledge bottleneck that kept the rest of the team out of the codebase.
• •Integrated the kiosk with third-party systems, adding insurance plans and phone top-ups as new revenue lines across every point of sale.
• •Built the Node back-end and the React front-end of the internal system used to manage the kiosks.
• •Built the company landing page with Next.js and TailwindCSS, used for lead generation and investor presentations.

Retail software company. Product portfolio management system.

• •Created the Vue.js design system from scratch, with over 20 components, adopted by 2 teams across 2 products, one of them already running in production.
• •Modeled database tables and wrote CRUD queries and REST endpoints in Node.js with Knex and MySQL.
• •Built Vue.js single page application screens to manage the product catalog, covered by Jest tests.