Federico Erostarbe

Worked on POAP (Proof of Attendance Protocol), one of the most beloved products in Web3, reaching hundreds of thousands of users at its peak.

Led the mobile engineering team behind POAP Home, the iOS and Android app where collectors discover, claim, and share their POAPs. Drove the app's development for over two years on a React Native / Expo stack using React Query, GraphQL, MMKV, Zustand, and R

Led the frontend architecture of Fuji Finance, a cross-chain money market aggregator in the DeFi ecosystem built on top of the Connext protocol, now Everclear.

Built a reliable, predictable UX around inherently complex cross-chain interactions, including wallet state, network changes, and transaction lifecycle.

Designed and integrated a custom TypeScript SDK to interact with smart contracts on a

Led frontend architecture for Fuji Finance, a cross-chain money market aggregator in the DeFi ecosystem built on top of Connext protocol (now Everclear). Designed and integrated a custom TypeScript SDK for smart contract interactions and contributed across the stack, including multicall support, testing, a Next.js serverless API with Redis caching, on-chain indexing, and CI/CD pipelines.

Led the backend engineering team responsible for Numio’s core API and infrastructure, built with Node.js and NestJS and deployed on AWS using Docker. Managed the stability and scaling of production services, including critical FaceTec-based KYC workflows and secure cloud backups.

Built a shared framework to handle multi-chain interactions with Ethereum and several L2 networks, including StarkNet,

Led development of a React Native mobile wallet with support for Ethereum L2 zk-rollups, including zkSync and StarkNet.

Owned a substantial refactor of the TypeScript production codebase while continuing feature development, requiring strict technical standards and CI discipline to avoid regressions.

Key functionality delivered included:

- First mobile implementation of NFT minting on zkSync Li

Led development of a React Native mobile wallet supporting Ethereum L2 zk-rollups including zkSync and StarkNet. Owned a substantial refactor of the TypeScript production codebase and delivered features such as zkSync Lite NFT minting, cross-layer swaps, DeFi lending via Aave, on-chain indexing with The Graph, and MoonPay fiat on-ramping.

Worked as a freelance mobile-first Product Engineer, mainly building React Native applications for early-stage startups.

Helped shape product definition, roadmap direction, UX strategy, and implementation, working closely with founders to balance technical trade-offs with business goals from initial scope through deployment.

On larger projects, served as a Technical Lead, coordinating other deve

Freelance mobile-first product engineer building React Native applications and native iOS/Android features for early-stage startups. Designed offline-first mobile architectures, implemented state-management patterns, set up CI/CD workflows, and served as a technical lead on larger projects.

Joined Coolr as the Founding Engineer, defining the initial technical architecture and building the MVP for an employee engagement product backed by Trilogy Equity Partners.

Key work included:

- Built the initial native iOS application in Objective-C
- Built the initial JavaScript backend
- Led a small mobile team as the product evolved
- Owned the most complex parts of the client application
-

Worked on several mobile applications with unusual product and technical constraints.

Selected work included:

- A mobile app that secured funding on Shark Tank, requiring custom motion and gesture tracking beyond what the platform readily supported at the time
- Whisper, an anonymous social media app that grew to tens of millions of active users
- Pixel-perfect UI implementation for high-traffic

Took ownership of a video-based iOS application in the EdTech language education space and increased its App Store rating by half a star, despite an already large number of reviews.

The app had millions of downloads, thousands of daily active users, and had previously been featured on the App Store.

Worked on performance and reliability challenges related to video-heavy content on early iPad har

Worked on early mobile applications in the FinTech banking and payments ecosystem, under strict security and compliance requirements.

Selected work:

- Multiple banking apps and the country’s first official ATM finder application
- A mobile wallet enabling QR-based payments, developed in partnership with Monedero, a major Argentinian contactless payments provider later acquired by Visa
- Early mo

Wrote regularly for Bitelia and ALT1040, two of the most widely read technology websites in Latin America.

I covered topics like digital privacy, open-source software, and hacking, aiming to explain how new technologies worked to a non-specialist readers, without the usual hype. This role was about technical communication, taking complex ideas and making them clear and accessible for the larger

Managed a team of up to fifteen journalists responsible for real-time media analysis.

Produced custom-written, client-specific reports that synthesized ongoing coverage, allowing clients to understand what was happening in the media as it unfolded.

Maintained direct, ongoing communication with clients, especially during crisis situations, helping them interpret coverage, anticipate consequences,

Worked on the media monitoring team responsible for tracking newspapers and broadcast news in real time, at a point when traditional media was the primary source of public signal and social platforms were not yet relevant.

Clients included local politicians, financial institutions, and PR teams from major national and multinational companies. While political coverage was a core focus, the work re