OPinit Stack


This section outlines the process for integrating Minitia with the Initia blockchain. The connection between Minitia and Initia is established using a Relayer that leverages the Optimistic Rollup technology from the OPinit stack, in conjunction with the Inter-Blockchain Communication (IBC) protocol. This integration facilitates seamless interoperability and secure transactions between the two chains.

The OPinit Stack is a versatile framework designed for CosmosSDK, facilitating the development of vm-agnostic Optimistic Rollups. This framework aligns closely with the interface of Optimism's Bedrock, promoting a straightforward user experience. Leveraging the Initia L1 Governance model, it addresses fraud-proof disputes efficiently.

Components of OPinit

The OPinit Stack comprises two critical Cosmos modules: ophost and opchild, alongside four L2-specific bot programs, ensuring a comprehensive ecosystem for application development.


The OPHost module serves as the foundation of the OPinit Stack, offering several key functionalities:

  • Bridge Interface: Facilitates the creation and management of the OP Bridge, including permissioned bridge executor and challenger roles.

  • Governance Integration: Allows the modification of Operator and Challenger addresses through governance proposals.

  • Batch Inbox: Records transaction batches from L2, maintaining them as transaction indexes, akin to Ethereum's calldata, rather than state changes.

  • L2 Output Oracle: Enables the registration of L2 output roots, accessible solely to permissioned bridge executors.

  • Management Features: Supports the removal of L2 outputs challenged by users, and the adjustment of operator and challenger addresses via governance messages, ensuring secure and flexible operation.


The OPChild module introduces three principal features to enhance the stack's functionality:

  • Module Replacement: Substitutes the staking, governance, and distribution modules necessary for employing CometBFT.

  • L2 Sequencer Generation: Produces L2 Sequencers for streamlined transaction processing.

  • Bridge Interface: Managed by permissioned bridge executors, it enables efficient cross-layer communication.

Bot Programs

The OPinit Stack is bolstered by four dedicated bot programs:

  • Bridge Executor

  • Output Submitter

  • Batch Submitter

  • Challenger

Bridge Executor

The bridge executor:

  • Stores the output information of the blocks on the minitia. This will be later submitted to the Initia L1 to ensure block finalization.

  • Monitors and records token transfer transactions between the L1 and the minitia

  • Records general information about the bridge configuration and the current state of blocks and transactions on the minitia

Output Submitter

The output submitter takes the output information recorded by the bridge executor and submits them to the Initia L1 to ensure that the minitia's block are finalized. This is done at a regular, configurable interval

Batch Submitter

The batch submitter handles aggregating transaction data stored by other bots into batches and submitting them to either the Initia L1 or Celestia to ensure data availability.


The challenger bot is responsible for monitoring and detecting invalid output proposals that are made by the output submitter and preventing them from being recorded on the Initia L1. If an invalid output is detected, it creates a record of it and sends a MsgDeleteOutput transaction on the L1 to dispute the proposal.


  • For comprehensive insights into the Inter-Blockchain Communication protocol, consult the IBC Official Documentation.

  • To understand the mechanics and benefits of Optimistic Rollup technology, explore resources on Optimistic Rollup.

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