I'm currently embarking on a project to establish a trustless bridge between a Substrate solochain and a parachain. Both chains utilize Substrate technology, with the solochain achieving finality through the GRANDPA gadget. To achieve this, I plan to use the technology provided by Parity Bridges Common.

In my understanding, there are two main components in the bridge:

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  1. Light Client: This is the core technology providing the state of the solochain in the parachain.
  2. Message System: An abstraction built on top of the light client to facilitate message passing from the solochain to the parachain.

For the initial stage, my aim is to integrate the light client of the solochain into the parachain. To achieve this, is it sufficient to incorporate the pallet-bridge-grandpa into the parachain's runtime and then run the relay to submit the "headers" of the solochain?

Any guidance or insights on this matter would be greatly appreciated.

Thank you in advance.

  • It will be more helpful if you can clarify what you are trying to do, are you making a bridge or just adding a light clinet? Jul 5, 2023 at 4:43

1 Answer 1


Yes, if your solochain is using GRANDPA for finality consensus, you can follow it from your parachain using pallet-bridge-grandpa light-client.

Besides deploying pallet-bridge-grandpa, you also need to deploy some offchain relayers to relay finality justifications across to the light-client. One such relayer implementation and documentation: https://github.com/paritytech/parity-bridges-common/blob/master/relays/finality/README.md

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