hello, I’m

Bernardo

Senior full-stack engineer.

I build the parts people see
and the systems they don’t.

I like turning complicated systems into products that feel simple. At Gnosis and impactMarket, that meant connecting interfaces, payments and blockchain infrastructure into clear, useful experiences.

A pen drawing of Porto’s Ribeira, the Douro river and the Dom Luís I bridge.

From commit to impact

These days

Building now

Independent projects

Passkey accounts, encrypted savings, recurring chores and safer spending policies. Small products with interesting problems underneath.

Explore the projects

What’s next

Open to full-stack/backend roles (founding roles too). Remote, up to UTC−4 and UTC+2.

Let’s talk

Aug 2024 – Sep 2026

Gnosis

Full-stack Web3 engineer

Joined in August 2024 when the product was called Metri. Built backend systems, product features and operations tools as it grew into Gnosis App.

TypeScript
Node.js
Svelte
Solidity
Envio

Selected impact

Expanded Envio indexing across Circles v1 and v2 for community discovery, trust connections, balance updates and demurrage calculations.
Built token swaps and a unified transfer/swap history. Gnosis App recorded approximately $703k in swap volume in Q2 2026.
Launched Circles-denominated card cashback for approximately 1,200 weekly users, with self-service payout tools and Intercom AI support integration to reduce manual investigations.

Details & tech stack

Reworked the transaction data model so transfers and swaps could share a faster activity feed despite their different event formats. Indexed the balances and metrics needed to calculate Circles demurrage.

For Circles-funded card top-ups, indexed token swaps, conversion to EURe and settlement so the app could display a simple outgoing wallet transfer and incoming card top-up.

Evolved cashback calculation scripts and payout CSVs into an internal tool the operations team could run independently. Added user-level reward investigations and transaction estimates, then exposed the relevant data to Intercom AI support.

Full technology stack

TypeScript
Node.js
Express
Svelte
Solidity
Gnosis Chain
Envio
GraphQL
Firebase
Vitest
Playwright
Claude

May 2020 – Jan 2024

impactMarket

Co-founder & CTO

As the first engineer, built the initial UBI contracts, backend and blockchain indexer, then led hands-on delivery across Microcredit, Libera Wallet and Learn & Earn.

TypeScript
Node.js
React
Next.js
Solidity
PostgreSQL

Platform reach

45k+: UBI beneficiaries
~30: countries

$3M+ distributed on-chain · 1M+ blockchain transfers

Details & tech stack

Combined indexed blockchain activity with private PostgreSQL profiles so communities could filter, sort and report on members without putting personal information on-chain.

Independently created the shared TypeScript and React SDK, giving the frontend team hooks for contract interactions, transactions, balances and rewards without handling smart contracts directly.

Built commercial Next.js features for nearly two years, using App Router and Server Components, and integrated the Prismic headless CMS.

Built backend services and SDK integrations for PACT donation mining, and reviewed the contracts implemented by our protocol partners. The programme attracted almost 800k cUSD from 4,000+ donors in its first two months.

Led Microcredit delivery from initial design through contract reviews, backend and SDK development, and the team’s UI implementation. The product delivered 500+ loans totalling $154k+ by year-end 2023.

Led engineering across Libera Wallet and Learn & Earn, remaining hands-on in the backend and SDK. Learn & Earn became the first dApp integrated into Opera MiniPay, initially launching in Nigeria.

Hired six engineers across backend, frontend, mobile and smart contracts while remaining hands-on in architecture and implementation.

Full technology stack

TypeScript
Node.js
Express
React
Next.js
App Router
Server Components
React Native
Prismic
Solidity
Celo
The Graph
GraphQL
PostgreSQL
Sequelize
Redis
Firebase
AWS Lambda
S3
CloudFront
API Gateway
Heroku
Docker
CircleCI

Selected evidence

Povoado de Jaguara — UBI community in Brazil

impactMarket presentation for Celo’s DeFi for the People initiative.

DeFi for the People — impactMarket on Celo

Aug 2018 – Apr 2020

Tech HQ

Blockchain developer

Delivered full-stack Ethereum applications for clients, from the interface to the contracts underneath.

Solidity
Ethereum
TypeScript
React

The work

Built and contributed to open-source contract libraries and application starter tools, including a smart-contract library with 450+ GitHub stars.

Created Solviz, a Solidity contract visualisation tool; developed it with a team to win 1st place at the 2019 ConsenSys Blockchain Grants Hackathon in Dublin.

Before that: Software Quality Assurance Tester at Altice Labs, Oct 2017 – Jul 2018. Automated testing with Java and Cucumber.

Details & tech stack

Published practical guides on upgradeable smart contracts, working with IPFS and human-friendly blockchain applications.

Full technology stack

Solidity
Ethereum
JavaScript
TypeScript
React
D3.js

Select a stop to explore the work.

Tools I work with

Across products, infrastructure and independent projects.

Web & mobile: React, Next.js (App Router, Server Components), Svelte, React Native, Prismic.
Backend & data: TypeScript, JavaScript, Node.js, Express, REST, GraphQL, gRPC, WebSockets, message queues, PostgreSQL, SQL, Sequelize, Redis, Firebase.
Blockchain: Solidity, Ethereum, Celo, Gnosis Chain, Envio, The Graph. Exploratory work with ZK proofs and fully homomorphic encryption.
Infrastructure & delivery: AWS (Lambda, S3, CloudFront, API Gateway), Heroku, Docker, Git, CircleCI; Cloudflare Workers and D1 in personal projects.
Testing: Vitest and Playwright at Gnosis; Hardhat for smart contracts; Java and Cucumber for automated testing at Altice Labs.
AI coding tools: Claude at Gnosis; Codex for independent work.

Recent projects

Real problems, useful software.

Kettigo

Independent project · Ethereum Sepolia prototype

Confidential prize savings with encrypted balances, private draws and passkey-controlled accounts.

Next.js · TypeScript · Solidity · Safe · Zama FHE

Details & tech stack

Built a mobile-first savings prototype using Zama FHE for encrypted balances and deposit-weighted prize draws. Integrated confidential USDC, passkey-controlled Safe smart accounts and sponsored transactions, with automated withdrawal processing.

Used Next.js App Router and TanStack Query for the app, plus Cloudflare Workers APIs and D1 storage for the landing-page waitlist.

The prototype runs on Ethereum Sepolia with test assets and prototype limits.

Full stack: Solidity, TypeScript, React, Next.js (App Router), TanStack Query, Tailwind CSS, Cloudflare Workers, D1, Zama FHE, Safe, Hardhat, viem.

Tiered spending guard

Independent project · Safe vault prototype

A Safe vault for spending limits, additional approvals and delayed withdrawals.

React · TypeScript · Solidity · Safe · Zodiac

Details & tech stack

Designed a Safe vault and React UI prototype enforcing on-chain spending limits, additional-signer approval and delayed, cancellable withdrawals.

Validated the core policy flows on Sepolia through adversarial and invariant testing, then published the architecture and testing findings.

This remains an unaudited research prototype on a test network.

Full stack: Solidity, TypeScript, React, TanStack Query, React Hook Form, Zod, shadcn/ui, Tailwind CSS, Safe, Zodiac, Hardhat, viem.

Mosaic

ETHGlobal Circuit Breaker · Hackathon project · Feb 2024

A hackathon prototype exploring private reputation through zero-knowledge proofs.

Noir · Barretenberg · Solidity · TypeScript

Details & tech stack

Explored a reputation system that could validate trust relationships without revealing users’ connections. The proof of concept kept the underlying social graph private while proving the relationships needed by the reputation system.

Built during ETHGlobal Circuit Breaker in February 2024. This was exploratory ZK work outside my professional roles.

Full stack: Noir, Barretenberg, Solidity, TypeScript, Hardhat, viem.

Task Cycle

Personal project

Recurring chores scheduled from when you actually finish them.

React · TypeScript · Capacitor · PWA

Details & tech stack

Finish a three-day chore on Tuesday and it’s due on Friday. Finish it late on Sunday and the next date moves to Wednesday. Editing a completion in your history updates the schedule too.

Tasks stay on the device. The app includes native reminders, import and export, and Portuguese and English interfaces.

Full stack: React, TypeScript, Capacitor, PWA.

Education

Bachelor’s in Computer Science — Software Engineering

Instituto Superior de Engenharia de Coimbra · Sep 2014 – Sep 2017