Quick note: This article has been written by Guest Author: <a href="https://medium.com/@msbivens0x?source=post_page-----61aa80dd3f1f--------------------------------">MSBivens0x</a> and we would like to thank him for this.When John pays Jane for a service rendered like completing an artwork commission or building an update website, John would simply send some pre-agreed amount of currency (let’s use $PAY as an example today) directly to Jane’s wallet. This is a simple transaction, boiling this down we have John sends 30$PAY to Jane. That’s it, that’s the whole transaction as it would be recorded on the blockchain. By all accounts it is a simple transaction, so why would we need anything more complicated than this?Going beyond this simple transaction system is necessary for unlocking a much greater potential application of blockchain transactions. We need complex transactions to improve data management and security, improve testing procedures, and increase capacity to work with use cases like the Internet of Things.A complex transaction might look like a smart contract taking the input “owner is home” and then executing code to turn on lights, have Spotify play smooth jazz, send a text to the wife saying you made it there, and turn up the heat because it’s winter. It could also look like you setting up a company-wide salary disbursement contract where it takes a timelock argument, reads the wallet addresses of registered employees, and then sends the appropriate funds to each wallet; maybe you even want to send the preferred ERC20 token that was agreed upon during the hiring process so the contract will also need to convert to that token from what you have in the treasury.<figure class="image image_resized" style="width:679.985px;"><img src="https://miro.medium.com/v2/resize:fit:588/0*Wgk20-CbRjXRvpUm" alt="" loading="lazy"></figure>Photo by <a href="https://unsplash.com/@lastnameeaster?utm_source=medium&amp;utm_medium=referral">La-Rel Easter</a> on <a href="https://unsplash.com/?utm_source=medium&amp;utm_medium=referral">Unsplash</a>It’s really hard to test these contracts, let alone actually get them to run because EVM chains have a limit on how complex a transaction can be, this is because the EVM is a stack machine. The stack has a maximum depth 1024 items where each item is a 256-bit word. In plain English, this means that your contract can only run so many commands before the transaction fails because it’s reached the stack limit. This limit imposed on the EVM extends to public testnets as well, so even if you wanted to run some research or testing on a contract to check out what might be possible with complex transactions, you can’t. You quickly realize that you need an alternative, you need a private testnet like what <a href="https://bit.ly/buildbear-app">BuildBear</a> can provide.<blockquote>Read more on the EVM stack on <a href="https://ethereum.org/en/developers/docs/evm/#:~:text=The%20EVM%20executes%20as%20a,256%20hashes%20or%20secp256k1%20signatures">ethereum.org</a>.</blockquote>BuildBear lets you setup and fully customize a private EVM node for you and your team to test your contracts in a way that outcompetes both local hosting and public testnets. The advantage of BuildBear is the freedom to have complete control over how this node operates, giving you control over an explorer and faucet, and still letting your team test it together. With your own faucet, there’s no concern over how much test eth is available or needed for complex transactions.<figure class="image image_resized" style="width:679.985px;"><img src="https://miro.medium.com/v2/resize:fit:588/1*CWhChas1KdLi9zFONKqUeA.jpeg" alt="" loading="lazy"></figure>During the setup process <a href="https://home.buildbear.io/create">here</a>, you’ll want to optimize your node settings for running these contracts during your testing. I recommend from the “Forking Options” to set a custom gas price (put it low but you can always take as much test ETH as you want) and allowing for unlimited contract size to override the restrictions. Turn off the “dropTransaction” setting from “Hardhat Options” and you should be all set to test away with whatever crazy and convoluted contracts you create!

What are Complex Blockchain Transactions?

Let’s get started then, Shall we?

Let’s get started then, Shall we?

Test DApps at Scale.