Connext is the interoperability protocol of L2 Ethereum.
You can use Connext to send transactions of value or calldata across chains and/or rollups. Unlike most other interoperability systems, Connext enables this without introducing any new trust assumptions or external validators.
Note that the current version of Connext cannot be used pass arbitrary event data between chains (i.e. prove to chain B that something occurred on chain A) as this cannot be done in a trust-minimized way in the evm except via existing rollup bridges.
This means that cases like migrating a token from chain A to chain B are not supported - you can instead only swap/transact over liquidity that already exists on the chain.
These docs contain information for developers integrating Connext and liquidity providers. If you're interested in contributing to the development of the system, check out the READMEs in our core implementation repo.
The background section covers high level information about crosschain interoperability and how nxtp, the protocol underlying Connext, works.
The developers section includes how to get started with integrating the Connext SDK in a browser/server environment, as well as how a lower level contract integration would work.
Routers are offchain nodes that provide liquidity and coordinate to facilitate interactions between chains. This section covers the basics of configuring and operating a router.
Don't know where to start? Come say hi in our community chat!