Our Impact

Over the course of multiple sprints, we helped Duffle transform into a robust, scalable, and feature-rich platform. Our work went beyond just fixing bugs; we implemented core infrastructure improvements like account abstraction, multi-chain indexers, and a dust management system. The project culminated in the development of a lightweight extension that brought Duffle’s powerful wallet directly into the browser, all while seamlessly handling a major SDK limitation. This comprehensive effort not only optimized Duffle’s core offering but also expanded its reach, giving users a frictionless, intuitive, and high-performance wallet experience.

The Client and Their Challenge

Duffle is building a next-generation wallet and exchange designed to make on-chain activity feel simple and fast. Duffle already has a very strong development team, but needed additional development support for new features. This falls under our staff augmentation model, where a Syntax developer(s) integrate directly into our partner’s team. The Duffle team had engaged Syntax to help with UX frictions, precision loss in token balances, and unreliable transaction bundling on chains like Solana. The existing wallet infrastructure lacked dynamic capabilities, and the team was looking for a solution that could support a universal login and seamless cross-chain functionality.

Why It Mattered

Integrating key features like universal login and cross-chain support was central to Duffle’s vision and the underlying technical challenges needed to be addressed with speed. Our focus was not only to address the immediate challenges but also to architect a scalable solution for the future, ensuring stability and enabling the development of advanced capabilities.

Our Approach

Our engagement with Duffle was structured as a series of focused sprints, beginning with tackling the most critical backend and frontend challenges, from addressing precision loss to fixing issues with the Solana transaction bundler. We then implemented core features, including a custom wallet infrastructure, seamless EOA wallet support, and a unified portfolio display that provided a single, accurate token balance across both EVM and Solana chains. A key deliverable was a robust batch transaction execution flow that could handle complex operations, including covering gas from a source token. To optimize the user experience and ensure smooth transactions, we also developed a sophisticated dust management and prediction system, which intelligently predicted and managed gas fees to prevent wallets from being fully depleted.

We also implemented account abstraction, which included a custom referral system and a Solana-specific setup. This also involved the use of UserOps for EVM-based chains and transaction bundling on both EVM and Solana to enable smart contract wallets and efficient transaction execution. For the referral system, we developed a system where each user transaction was placed in a queue. Our custom Solana and EVM indexers would then pick up these transactions, index them, and feed the data to the referral system. We also enabled chain abstraction by integrating over 10 new chains and using a headless approach to deliver a streamlined UI.

The project’s final phase was the development of the browser extension. We built it using a React-first architecture that provided a developer-friendly abstraction over Manifest v3. The most critical hurdle was integrating Privy for authentication, as its SDK was not built for browser extensions. Our solution was an innovative bridge system: a lightweight web app ran the Privy logic, and the extension communicated with it via message passing. This preserved the seamless user experience while working around a major technical limitation.

Results

Syntax delivered a complete, production-ready solution that not only addressed Duffle’s core technical challenges but also set them up for long-term growth. The initial stabilization sprints gave Duffle a reliable, high-performance platform, and the implementation of account and chain abstraction positioned them at the cutting edge of web3 technology. This project was a testament to our team’s ability to solve complex, multi-faceted problems, from foundational infrastructure to advanced feature delivery.