BUIP187: CashScript Port To Nexa

BUIP187: CashScript Port To Nexa
submitted by Singularity
date 28 Dec 2022


While Nexa script unlocks a huge amount of smart-contract capability, it has a very steep learning curve to be able to make use of it. Even with a good understanding of script, it can still be very cumbersome to work with compared to more common programming languages.

If we want a large number of developers and businesses to come and built incredible products and services on top of Nexa, it’s important that we reduce as many barriers as possible. We should want developers to be able to come in and build new financial services quickly and easily.

One thing we can do to reduce this barrier is to provide a higher-level programming language for Nexa smart-contracts. This will provide a more familiar interface to interact with the Nexa network in a complex manner.

If we have to start from scratch to produce this it will take a significant amount of time, and during all of this time, the barrier will still be driving potential developers a way. Therefore it is important to find the quickest path to providing such a tool.

CashScript is such a tool that already existing for Bitcoin Cash. It is a tool to develop smart-contracts using a highly simplified, javascript-like language. It allows developers to build, manage and interact with smart-contracts on the Bitcoin Cash network. In my opinion, porting CashScript over to Nexa would be a sensible project to implement.


  • Produce a new high-level language and smart-contract tool to develop Nexa smart-contracts.
  • Port CashScript to work with Nexa.
  • Add some of the new functionality in Nexa such as GROUP tokens.
  • Fork the CashScript website and add documentation specific to Nexa.
  • Have all work complete by the end of April 2023.


Budget of $35,000. For example, if the developer or dev group, require $75/h then this budget will cover 400 hours, or 2 and a half months of full-time work, to build the project with $5000 left over to cover the cost of maintenance.

The elected BU officials: President, Secretary and Developer will jointly agree expenditures for this BUIP and will monitor progress through regular reviews.


A competent developer with the required experience has already been found for this project, but if something changes and someone else needs to be found then the elected BU officials: President, Secretary and Developer will jointly agree on any person of team needed to complete the project.

This project is not an open bounty.


The person or team who is hired for this project will be expected to also provide at least 12 months of software maintenance, including bug fixes, and any updates needed to keep the software functional and secure. This is included in the budget.

Bitcoin Unlimited will be expected to maintain the hosting for any websites that are required for the project.


Any new software assets that result from this project will be owned by B.U. Org and will be provided open-source under the MIT license.

Expected Impact

  • Reduce barriers to entry for developers to build smart-contracts on Nexa.
  • Speed up development time for Nexa tools and services.
  • Increase the number of developers coming and building on Nexa.

This BUIP187 has today been updated based on feedback received, to provide increased clarity, and a increase in the budget has been included to cover the cost of 12 months maintenance.


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