I'm working on an idea where I would want my substrate-based blockchain (let's name it Blockchain A) to read events from another substrate-based blockchain (let's call it Blockchain B) and perform some actions on the basis of those events. For example, let's suppose I would want to read the TX events from Blockchain B so that when there's a TX of more than 100 tokens, I would want my Blockchain A to trigger an action in response to that event.

Is it possible to build something like this in Substrate? I've seen that there's this substrate_rpc_client pallet that has some helpful methods to do this, but I'm not sure where I would configure it in the outer node of my blockchain.

Any help in this regard is quite appreciated.

2 Answers 2


With the help of XCM you can do this.

Implementing cross-chain communication, such as through the XCM protocol, can be challenging due to the lack of comprehensive documentation. However, you can draw inspiration from successful implementations of the cumulus git hub you can get a idea from pink-pong pallet By leveraging your ingenuity, you can devise a strategy to integrate XCM-like functionality into your blockchain. This will involve understanding the underlying principles of cross-chain messaging, designing a compatible architecture, and ensuring robust security measures.

  • I doubt that XCM could help me in this regard. I don't want Blockchain A to send any type of confirmation to Blockchain B, whether it has performed any action or not. I just want Blockchain A to read events from Blockchain B and invoke its own implementation independent of Blockchain B.
    – Discardo
    Aug 7, 2023 at 19:10
  • You can draw inspiration from the Ping Pong pallet, which is available on a GitHub repository I provided your before. This pallet offers valuable insights into implementing cross-chain communication. By studying its codebase and design, you can gain a clearer understanding of how to integrate similar functionality into your own blockchain project. Aug 8, 2023 at 5:06

It could be possible to design an application with an event subscriber with the help of polkadot-js and then use it also to submit events to your blockchain B. However the process can be quite involved depending on what you want to do. I suggest going through the documentation on submitting extrinsics and reading events.

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