Exa App

Context

Exa App is a self-custodial wallet with a Visa card. People deposit crypto and earn yield on it, then spend with the card: they pay now from their balance, or split a purchase into up to nine fixed-rate installments borrowed against their own crypto, with no bank account or credit score. Exa Labs never holds their funds, and it neither issues the card nor lends: a licensed issuer issues the card under Visa, and the credit comes from the open-source lending markets of Exactly Protocol. The wallet is a smart contract account, so people sign in with a passkey instead of a seed phrase and the app pays their gas. It runs on OP Mainnet and on Base. One Expo codebase ships iOS, Android and the web, and a Hono server sits behind them. The monorepo is public on GitHub.

Since June 2026 I have led its frontend team. I joined in July 2024 as a senior frontend developer.

Problem

Money in a self-custodial wallet lives across networks and assets. Every feature has to work for someone who never thinks about chains, gas or bridges, on a phone and in a browser, from the same code.

Constraints

• The keys stay with the user, in their passkey, so the app has to prevent mistakes that nobody can undo afterwards.
• One codebase serves iOS, Android and the web.

Approach

• Core flows: onboarding, card management, payments and portfolio, integrated with Exactly Protocol’s on-chain markets for deposits, borrows and installment payments.
• Server: integrated identity verification through Persona with card issuance and card freezing, and fixed a stale web HTML cache that served outdated pages.
• Base launch: shipped the app side of the Base network launch (token integration, bridging, swaps and funding flows) with the backend and smart contract teams.
• Multi-chain swaps: implemented multi-chain swaps, on top of recovering assets sent on other networks and batched calls with sendCalls.
• Send to any network: sending any asset to any network, Bitcoin and Solana included, with the swap or bridge routed through LI.FI, and a gas policy that pays bridge fees with the tokens already on that network.
• Tokenized stocks: a distinct interface for tokenized stocks, the Coinbase-issued tokens on Base that track US shares and trade through swaps.
• App shell: app routing, deep link entry and support chat from any route.
• Quality: extended the Maestro end-to-end tests for payment flows on iOS and Android and traced release blockers to their root cause, including bugs in third-party libraries. I reported some of them upstream.

Outcome

• Three languages: the app ships in English, Spanish and Portuguese since I set up its localization in May 2025.
• Releases: about one mobile release a week, since the first in November 2024.