IgnacioContreres

Software Developer Consultant

Fingerprint is a device intelligence company. Its platform and the popular open source FingerprintJS library help businesses identify visitors and prevent fraud. I work with their web team building event, webinar and product demo pages and the integrations that turn registrations into sales meetings.

• Build event and webinar pages with Astro and React, and as custom React code components in Framer
• Built pages for in-person and partner events, including a Mercedes-Benz event and a Kraken event
• Turn designs into pixel-accurate, responsive components (borders, shadows, typography) for desktop and mobile
• Build Framer demo pages showcasing FingerprintJS integrations
• Migrated demo components from FingerprintJS v3 to v4, updating the loading and identification APIs

Software Engineer (AI) Consultant

Rozin Security builds a threat assessment and case management platform used by public safety teams and law enforcement agencies. Because of the data it handles, every feature needs a lot of care with security, accuracy and reliability. I own features end to end (from the React frontend to the Node.js and PHP backend) and I build the AI features of the product.

• Build LLM-powered features for the platform using Claude (Anthropic API)
• Proposed and led the migration of the whole system from JavaScript to TypeScript
• Own features end to end across frontend, backend and AI layers
• Build complex multi-step workflows and data-heavy tables and dashboards
• Work directly with the team on how features should work, not only on implementation

Mobile Developer Consultant

JustiFi is a payments platform. I worked on their React Native payments SDK, building native banking forms in Swift (iOS) and Kotlin (Android) that developers add to their apps to collect banking information.

• Designed banking forms around compliance constraints with security as a core requirement
• Built forms natively in Swift and Kotlin so sensitive banking data is handled in the native layer, not JavaScript
• Validated and sanitized input to prevent malicious data injection through the forms
• Packaged the SDK with react-native-builder-bob across Swift, Kotlin and JavaScript
• Invested heavily in research and planning; compliance requirements and attack surface were worked out before writing code

Frontend Developer & Frontend Lead

Diligent AI is an AI product for due diligence. It processes large volumes of documents and uses AI to surface the information that matters before an investment or acquisition. I started the frontend from scratch and was the frontend reference for the project.

• Started the frontend from an empty repository; defined the architecture, conventions and patterns
• Chose Jotai for client state and React Query for server data, keeping UI state and remote data clearly separated
• Built a document viewer that renders PDFs with OCR-mapped text, so AI findings are highlighted directly on the page
• Worked closely with the data science team to define the product logic and shape what AI results looked like in the UI
• When a second frontend developer joined, they built on the foundation I set

Full-stack Developer

Loop Me In is a social dating app with around 60k users. I worked mostly on the backend, building the social features at the core of the product: friends, friends of friends, the feed and filters. I worked directly with the CTO, a former engineering manager at Facebook; his engineering practices shaped a lot of how I build software today.

• Modeled user connections for direct friends and second-degree (friends of friends) lookups with scale in mind
• Built the feed backend end to end: Prisma data model → NestJS service → GraphQL queries
• Implemented server-side filters in the GraphQL API so the app only receives matching results
• Typed end to end: Prisma models, NestJS services and GraphQL schema all in TypeScript
• Built the Next.js marketing landing page

Frontend Developer

At Effectus I worked across three client products using React and React Native, building frontend features from shared foundations and owning delivery across the full frontend.

• Built features across React and React Native projects from shared component foundations
• Built group and 1:1 chat with Twilio across two separate apps
• Designed GraphQL schemas for owned features, built SMS-based MFA, and built PDF upload/download with S3
• Worked directly with CTOs and clients, presented demos, reviewed code
• Covered areas from real-time messaging to medical content and driver qualification flows

Frontend Developer

At GlobalUY I worked on two B2B data intelligence products, building data-heavy UIs and owning epics end to end.

• Built custom components for filtering experiences and data-heavy table views
• Owned epics end to end: estimation, development, demos to clients
• Worked across React, Redux, TypeScript and AWS Lambda backends
• Reviewed teammates' code and helped shape planning decisions

Automation Engineer / Frontend Developer

I spent my entire time at Ascentis on the reporting module of their HCM platform, first on test automation, then on frontend development. Working on both the testing and development of the same module gave me a strong sense of quality and edge cases that I still bring to every feature.

• Automated test cases for report generation and report filters with Python, Selenium and Robot Framework
• Built custom React and Redux components to create reports and export them to PDF and Excel
• Estimated user stories and bugs, helped plan sprints and prioritize the backlog
• The overlap between QA and dev gave me a deep appreciation for edge cases and quality

Full-stack Developer

My first professional role. I worked across the full stack on a web app to manage the construction of educational centers, plus an internal CRUD tool. Working across every layer early on gave me a solid understanding of how a web app fits together.

• Worked across the full stack: React frontend, Node.js backend, MySQL database
• Built reusable components to keep the UI consistent and speed up new features
• Set up the project configuration and introduced key libraries
• Reviewed teammates' code and worked in Scrum with 2-week sprints