L2 protocol Connext and everything you should know about it

3 min readDec 11, 2021

This article is designed to go by basic to complex and includes links.

As we all know, scaling Ethereum is a huge problem that is need to be solved from many angles at once. Finally Layer2 solutions in Ethereum are about to change whole game and one of the most important protocols on L2 is Connext. You’re about to learn everything you should know about it.

What is Connext? It’s the interoperability protocol of Ethereum Layer2. It’s started to be build in 2017 with a mission of ‘fast, noncustodial crosschain communication’ and today it’s live on mainnet and is audited.


You can use Connext to send transactions of value or calldata across chains and rollups. Unlike most other interoperability systems, Connext enables this without introducing any new trust assumptions or external validators.

Is not an exchange or dApp. It’s a protocol made up of many routers (independent liquidity/infrastructure providers) that enables communication between chains. Developers can build crosschain applications (exp: DEXs) on Connext.

It does not have access to your funds. Because of how Connext is designed, the security of the system is the same as the security of the underlying blockchain; even if every single router in its network were to collude with each other, there would be no way for them to access your funds.


Connext team is only a protocol implementer and does not charge any fees, fees are charged by routers when users send transactions.

It enables sending value and calling contracts across Ethereum-compatible chains and L2s. Currently supports 9 chains: Ethereum, Binance Smart Chain, Polygon, xDai, Fantom Opera, Arbitrum One, Avalanche, Optimism, Moonriver. See other planned other chains and testnets here.

Projects and protocols are actively being build on top of Connext and one of them is xPollinate, UI for bridging across chains, a bridge. I’ll be publishing a simple guide about how to use xPollinate soon too.

Does not have a token at this time. Beware of scams.

If you’re a developer who is looking forward to build on Connext, here are detailed sources for you:

How Connext works: Transaction lifecycle and architecture

Connext vs. other interoperability solutions: Pos/MPC Systems/Hop/Optics/simple atomic swaps

Security model: Risks, Loss of funds & DoS and Griefing

Guide and API reference


They launched a Ecosystem Grants Program with the goals below:

  1. Foster the development of the Connext ecosystem through targeted resource allocation.
  2. Give independent projects and working groups ownership of key parts of Connext.
  3. Provide teams with ongoing support as they continue to build with Connext.

You can find the ecosystem grants portal here.

Rahul Sethuram’s workshop on building cross-chain applications with Connext:

xPollinate by Whiteboard Crypto:

Join Discord community.