Streamlining Sei's Architecture to Focus Solely on EVM

Supporting both EVM and CosmWasm has helped attract a wide range of users and developers. But this dual-architecture approach has also created serious headaches.

As Web3 technology rapidly advances, new protocols are continually being developed to improve the user experience and drive adoption. Among the innovations that have emerged in recent years is the integration of various programming models for smart contracts.

One protocol that has been at the forefront of this integration is Sei. In its v2 version, released in 2024, Sei introduced support for both the Ethereum Virtual Machine (EVM) and CosmWasm, a WebAssembly-based system used by Cosmos chains. The aim was to provide maximal flexibility for users and developers in deploying and interacting with diverse applications.

However, a new proposal submitted through the Sei Improvement Proposal (SIP) process suggests streamlining Sei into a fully EVM-based chain. This proposal, which is being put forth by @Sei_Labs, aims to reduce the complexity of developer experience, infrastructure maintenance, and user interaction with the network.

Why Dual Support Became a Double-Edged Sword

In theory, letting users interact with both Cosmos-native and EVM-based apps was a win for flexibility. Sei’s architecture allowed interoperability between Ethereum’s EVM and Cosmos’s WasmVM, a WebAssembly-based system that powers smart contracts. But in practice, the setup created several sticking points.

Users have to manage two separate wallets—EVM and Cosmos—and manually link them to access the network’s full features. For developers and infrastructure providers, the situation is even more tangled. Indexers, explorers, and node operators must write custom logic to sync data between two incompatible systems. This overhead increases code complexity, introduces bugs, and slows development.

SIP-3: A proposal from @Sei_Labs to streamline Sei’s architecture to an EVM-only model has been submitted through the Sei Improvement Proposal process.

This proposal aims to enhance developer experience, simplify infrastructure, and fully leverage Sei’s parallelized EVM… pic.twitter.com/nxQ9cGYXj2

— Sei 밝은 빨간색 (@SeiNetwork) 5월 7, 2025

The numbers speak volumes. Since the release of Sei v2, EVM-based usage has skyrocketed. According to on-chain analytics from SeiScan, over 85% of transaction volume on the network is now being generated by EVM addresses. Popular apps like Astroport, which recently migrated from Terra to EVM-compatible chains, are also contributing to this trend. The market is speaking—and it’s leaning heavily toward EVM.

The Proposal: Moving to an EVM-Only Architecture

The new governance proposal recommends sunsetting CosmWasm support and concentrating fully on EVM. Under this plan:

Only EVM addresses will be able to initiate transactions on the network.

New CosmWasm deployments and IBC transfers will be disabled.

Execution of CosmWasm contracts and native Cosmos transactions will be phased out.

Internal protocol features like staking and governance will still function via precompiles, meaning core functionality of the protocol will be maintained even as external code is sunsetted.

Technically, the transition will depend on a few key milestones. One is the creation of “EVM pointers,” which will allow seamless access to existing Cosmos assets from the EVM side. The next steps will involve the complete shutdown of CosmWasm contract deployment and, finally, the termination of legacy interactions with the CosmWasm runtime.