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Developing Cross Chain Dapps
If you haven't read the Wormhole introduction to understand what Cross Chain Development is and how developers and Dapps can benefit from it, please start there.
VAAs are the core messaging primitive in Wormhole. You can think of them as packets of cross chain data that are emitted any time a cross chain application contract interacts with the Core Contract.
Relayers in the Wormhole context are processes that deliver Verifiable Action Approvals (VAAs) to their destination, playing a crucial role in Wormhole's security model. They can't compromise security, only liveness, and act as delivery mechanisms for VAAs without the capacity to tamper with the outcome.
When building a cross chain application, there are two primary ways to relay messages (VAAs) with Wormhole.
- 1.
- 2.
The components outlined in blue are those that must be implemented by the developer
Automatic Relaying is currently only supported for EVM environments.

Standard Relayer
With Automatic Relaying, only the contracts need to be developed. Leave the message delivery to a service provider.

Specialized Relayer
With Specialized Relaying, the developer can communicate with any blockchain Wormhole supports and has the freedom to choose a delivery strategy.
Last modified 25d ago