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FinTech · SaaSOngoingOpen Source Contributor · Guest Engineer
New Expensify
Chat-Based Financial Collaboration
Contributed 50+ merged pull requests to New Expensify — the production React Native app used by millions for chat-based expense management — working through Expensify's fully public open-source process alongside their core engineers, and recognized with a Guest Engineer invitation to their Curaçao offsite.
50+
Merged pull requests
Millions
Users on platform
Guest
Engineer, Curaçao
OSS
Public contribution model
React NativeTypeScriptGraphQLReal-time ChatOpen Source
github.com/dhairyasenjaliya →Product Preview
The Challenge
Building a real-time financial product at massive scale
- —Expensify needed a mobile experience that matched the complexity of their web platform — chat-based expense reporting, receipt scanning, and team workflows.
- —The codebase serves millions of users with strict performance, accessibility, and reliability requirements.
- —Contributions required deep understanding of production React Native patterns at enterprise scale.
Product Goals
- ✓Ship high-quality features to a production codebase with rigorous review standards
- ✓Maintain performance across iOS and Android under real user load
- ✓Collaborate with a distributed engineering team across time zones
The Solution
Production-grade contributions to a world-class RN codebase
- —Picked up open issues from Expensify's public GitHub board, proposed an approach, and shipped each fix or feature as a pull request reviewed by their core engineers before merge.
- —Cleared a deliberately high bar on every one of 50+ merged PRs — strict TypeScript, unit and end-to-end tests, and multiple review rounds against a shared style guide.
- —Worked inside a chat-first, offline-capable UX built on react-native-onyx, keeping state in sync in real time across iOS, Android, and web from a single codebase.
- —Iterated directly with maintainers across time zones — addressing review feedback, resolving regressions, and matching patterns used throughout the app.
Architecture
- ✓React Native with TypeScript strict mode
- ✓react-native-onyx offline-first state layer
- ✓GraphQL API with optimistic updates
- ✓Automated CI — lint, type-check, and tests gate every merge
Technical Highlights
How It Was Built
React Native & TypeScript (strict)
react-native-onyx offline-first state
GraphQL data layer with optimistic updates
Real-time chat & notifications
Unit & end-to-end test coverage
Public open-source contribution workflow
Lessons Learned
- →Enterprise React Native requires discipline in architecture, testing, and review culture
- →Open-source contribution at scale teaches patterns that transfer directly to client work
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