Informal Systems Teams Up, with Polymer Labs and Cosmos Developers 🌟

Polymer Labs has collaborated with Informal Systems and the Cosmos development teams for a conversation regarding advancements in Polymers structure. The dialogue took place on X Spaces by Informal Systems a research entity within the Cosmos community. The main topic of discussion centered around Polymers shift from being a Cosmos chain, to adopting an Ethereum Layer 2 (L2) solution.

📌 Why did Polymer switch from a Cosmos Appchain to an Ethereum L2?

Polymer’s goal is to tackle the distribution challenge for IBC technology. Initially, the plan was to solve this issue by operating as a sovereign appchain within the Cosmos ecosystem. However, as the rollup thesis gained traction, especially on Ethereum, it became clear that a sovereign appchain wasn’t the best fit for rollup-to-rollup communication. The native IBC integrations were taking too long, and adding a third-party validator set could compromise the security properties of cross-rollup communication.

In response, Polymer decided to evolve into an Ethereum Layer 2, which allowed the project to inherit the security benefits directly from Ethereum’s settlement layer.

📌 How far along was Polymer in building the Cosmos chain before deciding to change architecture?

Polymer was nearly complete when the decision was made to pivot. The good news is that the team realized they could retain the Cosmos SDK application code while transitioning to the L2 architecture.

📌 What’s the new stack, and how do the components interact?

The new architecture combines the Cosmos SDK for the execution layer with the OP Stack for settlement and chain derivation logic. The OP Stack’s Engine API, originally designed to separate Ethereum’s consensus and execution layers, was adapted to work with the Cosmos SDK’s ABCI (Application Blockchain Interface). This enables Cosmos SDK applications to function as the execution engine atop the OP Stack, instead of relying on OP Geth.

📌 Were there any limitations in the Cosmos SDK that are now resolved with the OP Stack?

RollKit, designed for sovereign rollups, lacks the chain derivation logic necessary for settlement on Ethereum. The OP Stack, in contrast, includes this essential functionality, along with other critical features like batch data posting and reorg handling.

📌 How does the OP Stack compare to the Cosmos SDK?

The OP Stack, while highly focused on solving the settlement problem, lacks the same level of customization and interoperability that the Cosmos SDK offers for app chains. However, Polymer’s approach leverages the strengths of both ecosystems by integrating the Cosmos SDK as the execution layer within the OP Stack.

📌 How did you choose the OP Stack over other options like Polygon’s CDK or Arbitrum?

The OP Stack was the most customizable for Polymer’s needs, allowing the team to replace the execution engine with a Cosmos SDK application. This hybrid approach merges the best of both ecosystems and supports experimentation.

📌 Is it true that OP Stack doesn’t have fraud proofs?

While fraud proofs aren’t yet live in production, several teams are working on it. The Optimism team has fraud proofs in testnet, and other projects like RiscZero are developing validity proofs. For Polymer, the work required to prove the execution side of the Cosmos SDK would have been necessary regardless.

📌 How does sequencer centralization impact the new architecture?

Sequencer centralization affects the liveness and censorship resistance of rollups, not their safety. For Polymer, using CometBFT as a decentralized sequencer within the new architecture could offer a robust solution that balances centralization concerns.

📌 How did the switch to L2 influence Polymer’s mission to connect everyone via IBC?

Polymer now views Ethereum similarly to the Cosmos Hub, with both practicing a form of protocol minimalism. By adding IBC to Ethereum as a Layer 2 solution, Polymer enhances cross-rollup UX and strengthens the hub-spoke model for interoperability.

📌 How does a rollup connect to Polymer?

Polymer’s Virtual IBC allows for permissionless IBC connectivity via smart contracts, with Polymer acting as an IBC sidecar. This setup lets connected rollups function as regular IBC chains within the network.

📌 What does this mean for IBC components, relayers, and clients?

Polymer reuses the ibc-go implementation and supports compatibility with existing IBC tools like Hermes. The new architecture allows rollups to rely on Ethereum for state verification, embedding IBC-compliant state within Ethereum’s state.

📌 What happens if all rollups adopt a similar architecture?

Polymer was designed with a future where IBC is ubiquitous in mind. Even in a scenario where all rollups on Ethereum have native IBC, Polymer would act as an optimization layer, enhancing the overall network topology and efficiency.

📌 What’s next for Polymer?

While Polymer currently deploys on Ethereum using the OP Stack, the team is open to exploring other settlement layers like Celestia. Polymer aims to form an IBC mesh, optimizing network topology across various domains as the ecosystem evolves.