NodeReal Tutorials  / Introducing the new Debug Pro API with JS customization
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Introducing the new Debug Pro API with JS customization

Debug tracer APIs give developers the insight of the code execution on the EVM, allow developers to debug, inspect and set certain debug flag during the execution.
Introducing the new Debug Pro API with JS customization


Debug tracer APIs give developers the insight of the code execution on the EVM, allow developers to debug, inspect and set certain debug flag during the execution. As a public infrastructure provider, NodeReal aims to provide the best service to web3 developers, including the debug API. As debug APIs are computing intensive, most of the service providers will not allow custom tracer to be executed because it may take most of the computing resource and impact other users. This has become a pain point for developers who want to hand over the infrastructure to the service providers and focus on the business logic. NodeReal aims to solve this problem by providing the Debug Pro API package.


Do you know that JavaScript (JS) is one of the most popular programming languages in the world? It's well-known for creating dynamic and interactive web pages that bring life to the internet. Thanks to its versatility, it's also a go-to choice for building robust web applications.

We've heard your requests to incorporate JS into the Debug API, and we're thrilled to announce that we now support the customization of Debug API with JS. We termed it the new and improved Debug Pro API. This means you can now have a more personalized debugging experience and identify and fix bugs in your code more efficiently. Get ready to take your development skills to the next level with this exciting new feature!

What’s new?

Debug API

Debug Pro API

Supported tracer Object type










*Custom Javascript*

Are you curious about what parameters are supported for Debug API and Debug Pro API? Look no further! Our table provides an overview of all the supported parameters, except for "Struct/opcode logger." We're proud to say that we support the majority of the built-in tracers published on Geth.

But what's even more exciting is the main highlight of our JS customization feature. With this feature, you can customize your debugging experience like never before. Say goodbye to generic debugging and hello to a more personalized approach. So why wait? Start exploring the power of JS customization in Debug Pro API today!

What to take note of?

When requesting Debug APIs, it is important to note whether JS tracers are enabled, as this will impact the charges incurred. If Javascript tracers are enabled, the request will be considered a heavy resource-consuming request and will be charged according to the CU standards of Debug Pro APIs. On the other hand, if Javascript tracers are not used, the request will be treated as a regular Debug API request and charged accordingly. The table below shows the CU usage for JS enabled tracers.

Debug API

CU usage

Debug Pro API

CU usage

















To track your Debug Pro API CU usage, head over to “My APIs” from the top menu selection.

How to Use Debug Pro API?


You will need an application up and running on the MegaNode Archive Node. Sign up for an Enterprise MegaNode account today at the following link. You will need the {API KEY} of the application when calling the request method.

Tools Required:


Before we start, you will need to log in MegaNode Service and find your API keys. Here is a quick guide to retrieve it.

Start exploring the page for more information, and do check out the API Docs here.

The Debug Pro API package is designed to help developers debug and troubleshoot smart contracts on the blockchain. While small and medium-sized enterprises (SMEs) may not have the in-house technical expertise to use these tools directly, they can still benefit from their capabilities by working with external developers or blockchain consultants who have experience with these tools. In the following paragraph, we will discuss how to use the Debug Pro API with Postman. We will be demonstrating with debug_jstraceBlockByNumber.

Debug Pro API-debug_jstraceBlockByNumber


• From blockNumber - The block number

• E.g. 25739778 (in decimal) = 0x188c202 (hex format)

• blockHash[REQUIRED] - The block hash


• tracer[REQUIRED] - The tracer type. Please refer to Geth implementation for more tracer type.

• E.g. bigramTracer


Use Cases for Debug Pro API

Here are a few ways that SMEs can make use of the Debug Pro API:

Testing and repairing smart contracts: Prior to their deployment to the blockchain, smart contracts can be tested and repaired using the Debug Pro API. This can aid SMEs in ensuring that their contracts are operating as planned and will do so after they go live.

• Troubleshooting issues with smart contracts: If an SME encounters issues with a smart contract on the blockchain, they can work with external developers or consultants to use the Debug Pro API to diagnose and fix the issue. This can help minimize downtime and ensure that the contract continues to operate correctly.

• Security auditing: The Debug Pro API can also be used to perform security audits on smart contracts to identify potential vulnerabilities and weaknesses. This can help SMEs ensure that their contracts are as secure as possible and reduce the risk of security breaches or attacks.

In general, SMEs should work with experienced blockchain developers or consultants who have experience with the Debug Pro API and other blockchain development tools.

Benefits of using Debug Pro API

Debug Pro API is a more advanced version of the Debug API that offers additional features and benefits. Here are some of the key benefits of using Debug Pro API:

• Performance: Debug Pro API is designed to offer comprehensive debugging compared to the standard Debug API. It provides detailed information about your code's execution, allowing you to identify and fix issues quickly.

• Customization: Debug Pro API offers more advanced customization options compared to the standard Debug API. You can tailor the debugging experience to your specific needs by customizing parameters like tracers, event listeners, and watch expressions.


In conclusion, Debug Pro API has a number of advantages over Debug API, including improved performance and comprehensive customization possibilities. These advantages can assist you in enhancing both the overall quality of your development process and the quality of your code and apps. Talk to NodeReal today and we can provide you with a one-stop blockchain infrastructure solutions and services.

About NodeReal

NodeReal is a one-stop blockchain infrastructure and service provider that embraces the high-speed blockchain era and empowers developers by “Make your Web3 Real”. We provide scalable, reliable, and enterprise blockchain solutions for everyone, aiming to support the adoption, growth, and long-term success of the Web3 ecosystem.

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