Substreams Support for Optimism

2 min readDec 20, 2023


With the addition of Substreams support Optimism, Substreams now offers support for five EVM-compatible chains (Ethereum, Polygon, BNB, Arbitrum, and Optimism). But this is just the beginning! More chains will be supported throughout 2024, thanks to the new RPC Poller technology that allows us to add support for new chains at an incredibly fast pace!

About Optimism
Ethereum, the largest blockchain platform for smart contracts, is a tested and secure network for dapps. However, Ethereum struggles with growth. The more congestion the network has, the higher gas fees continue to grow. This creates a huge issue, as it brings a degraded UX through increased costs and slower response times.

Rollups help solve this through batched transactions. For example, consider 5 different users each making a transfer of USDC. You could rollup those 5 transfers within the same transaction, thus reducing the number of transactions from 5 to 1. This is the approach that Optimism takes on top of the Ethereum mainnet.

Transactions executed in the Optimism network are posted to the Ethereum network in batches. This happens using optimistic rollups, which essentially means that any transaction posted to Ethereum is correct unless proven wrong. There is a window time in which users can send fraud proofs for specific transactions. Optimism, like other optimistic rollup chains, assumes that transactions are going to be correct virtually all of the time.

Getting Started with Optimism in Substreams
You can run Optimism Substreams by using the StreamingFast-provided endpoint (, which you can also find in the Substreams documentation.

Optimism uses the same data model as Ethereum, so you will be able to develop Substreams easily on this new blockchain.

If this is your first time building with Substreams, simply create an authentication key in the StreamingFast portal to get started on Optimism. Also check out the StreamingFast Discord and The Graph Discord, which are great support tools for any questions you may have along the way.




StreamingFast is a protocol infrastructure company that provides a massively scalable architecture for streaming blockchain data.