SIP-8: Move Marketplace to sidechain(s) & start multi-chain strategy

The gas fees on Ethereum mainnet have been extremely high for a long period of time. For this reason, creating products or Data Unions as well as making purchases on the Streamr Marketplace is prohibitively expensive.

The Streamr team has been working on a multi-chain strategy, which enables the Streamr ecosystem to be deployed onto many chains and interoperate. But this will take a bit of time to implement and deliver. In the meanwhile, a quick fix would be welcome. For this reason, I propose splitting the work into two steps - a quick win and a longer-term follow-up:

• Step 1: As a quick fix, move the Marketplace as-is to the xDai chain. Why xDai? The current Data Unions exist on xDai, and it’s probably best to maintain compatibility between existing Data Unions and the Marketplace at all times.

• Step 2: Implement a multi-chain approach, where the Marketplace, Data Unions, and other Streamr smart contracts will exist on multiple EVM chains, creating an ecosystem that spans across different sidechains and L2s.

More thoughts about the multi-chain approach

The Streamr Network, Marketplace, and Data Unions jointly use a number of smart contracts to operate. Ideally, they would all exist on one and the same chain, which would be scalable, cheap, and popular. In the current blockchain offering, no such “one chain to rule them all” exists, instead there are various sidechains and L2s, each with their unique properties.

As the space is so fragmented, and the popularity of different chains changes quickly, Streamr should at least build the capability to run the protocol in parallel on several EVM-based chains, and deploy the system to new chains as needed. This creates new audiences for the technology as well as provides partnership opportunities with the sidechain and L2 teams.

In the approach, basically a full suite of Streamr contracts is deployed on each supported chain. The state of each chain is then merged on the application level: for example some of your streams or products could be defined on one chain, and some on another chain. This is a little bit similar to SushiSwap for example, where a copy of the system basically exists on all chains, and you can trade or provide liquidity on the chains you choose.

Pros/Cons analysis

Pros

• Solves the gas cost issue on the Marketplace, both short and long term
• Provides a multi-chain strategy and trajectory for the whole Streamr system

Cons

• It’s somewhat harder to get assets and use dApps on sidechains. On the other hand, gas costs on mainnet make dApps impossible to use as well
• Sidechains are not as secure as Ethereum mainnet
• More complexity in the overall system