Transaction tracing is the process of extracting detailed information about each step of the transaction. This article explains how transaction tracing works and the difference between two transaction tracing methods: **trace_call** and debug_traceCall.
Before reading about how transaction tracing works and the difference between tracing methods you should have a clear understanding of EVM, Execution Clients, Smart Contracts and Nodes. You can read about these topics in the official Ethereum documentation. However, if you just need a refresher, you can find the one-line definitions for these topics below.
<aside> 💡 These definitions are not meant to be complete explanations. Instead, they are just refreshers for the people who already know about these concepts. For a detailed explanation please refer to the official Ethereum documentation.
</aside>
There are two types of transactions in EVM-compatible protocols:
The downside of the contract execution is that it is very hard to tell what the transaction actually did. When a transaction` is executed, you can get a transaction receipt that contains a status code to check whether the execution succeeded or not, but there is no way to see what data was modified, or what external contracts were invoked.
Look at the transaction flow below:
This is a transaction in which a user (externally owned account) invokes a contract which in turn invokes another contract and this is how the transaction receipt for this transaction looks like: