Frequently Asked Questions

What is LayerZero?

LayerZero enables messages to be sent between blockchains.

How do I send a cross-chain message?

See example contracts here and here, and details on sending messages here.

What blockchains are supported?

See a table of supported blockchains. The team is always working to add more chains, so check back frequently!

What is a User Application?

A User Application (UA) is any contract that uses LayerZero to send & receive messages between blockchains.

What is an Endpoint?

The deployed contract on which your User Application calls send() to transmit messages and set its own UA configuration. Heres is the list of endpoint addresses with which you may interact with.

What is an Ultra Light Node?

The UltraLightNode.sol is a smart contract at the heart of the message protocol, sitting behind the Endpoint, it enables all the features of LayerZero. In the future, UAs will benefit from new versions of the Ultra Light Node, but for now there is only one highly optimized version (v1) of the ULN.

What is an Oracle?

An Oracle is required by each User Application and assists in sending messages. User Applications use the default Oracle automatically so you don't need you configure it, but you can if you want to.

What is a Relayer?

User Applications use the LayerZero Relayer by default, without additional configuration. However, a Relayer is required by each User Application and plays a crucial role in delivering cross chain messages. If desirable, User Applications may be configured to use a different relayer.

Technical Section

Two modes: Blocking and Nonblocking:

LayerZero UserApplications can choose to be Blocking or Nonblocking (see the examples). All messages are nonce-ordered, which means they will arrive from a source chain & source UA address in the order they are sent. By default, messages will be queued if there is an out-of-gas, or logical error on the destination.
If contract developers wish to avoid the default blocking mechanism, instead use NonblockingLzApp which will continue with the flow of messages, a design which stores out-of-gas messages on the destination to be retried (by anyone) at anytime.

Can LayerZero users enjoy the benefit of any future optimized proof technology, e.g. ZKP based?

Yes, LayerZero has the ability to add new Messaging Libraries. LayerZero Labs will keep bringing the best research into production. Existing users can easily perform a library migration on-chain.