Building a Better Transaction Builder

2 min readOct 23, 2023


The team has been hard at work since the launch of the DEx to optimize its capability, as well as enhance the user experience. Whenever a user conducts a transaction on Cardano, the dapp must build the transaction to submit to the blockchain. There is no standard practice for building transactions on the Cardano Blockchain, rather each project needs to optimize this process for their system. The VyFinance platform is complex, and contains many different possible functions, each with their own set of edge-cases.

As transaction building is vital to the user experience, we have placed a large part of our focus on optimizing this process. We have just released the largest update to our transaction builder to date, which will see multiple changes to the way we are building transactions on our site. This update would have been imperceptible to the user from a visual perspective, but there should be a noticeable decrease in error messages when submitting transactions to our DEx.

We have implemented three major changes, and the capacity to deal with hundreds of edge-cases.

The major changes are:

UTxO Selection Algorithm

  • The builder will prioritize the largest UTxO in the wallet when building transactions. This will reduce the possibility of low-ADA error.

Improved Output Sizing

  • This optimizes the output UTxOs. This will result in lower error rates when submitting transactions.

Removal of PAB Dependency

  • We were pulling data, and building the datum for transactions from the PAB, now it is exclusively done through the browser. This will reduce the transaction pop-up time.

There should no longer be a need to use the Token Fragmentation when larger wallets are using our site. This feature is still available to use, and can keep your wallet optimized. To learn more about the Token Fragmentation, you can read here:

Along with these major changes, there have been a slew of solutions for edge cases that have been implemented. This will reduce the total errors when building transactions on the platform as a whole, and should result in a much smoother user experience. These Bug fixes will increase the capacity of the platform into the future.

With this implementation, we hope to deliver the smoothest user experience yet in the VyFinance dapp!

A special thanks to the community for alerting us to bugs, and being patient with us while we fix them. Without you, this wouldn’t be possible!