> For the complete documentation index, see [llms.txt](https://docs.nomad.xyz/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.nomad.xyz/developers.md).

# Developers

- [Quickstart](https://docs.nomad.xyz/developers/quickstart.md): Your one-stop shop to start building cross-chain applications (xApps).
- [Send Messages](https://docs.nomad.xyz/developers/quickstart/send-messages.md): The on-chain API for sending cross-chain messages
- [Receive Messages](https://docs.nomad.xyz/developers/quickstart/receive-messages.md): The on-chain API for receiving cross-chain messages
- [Environments](https://docs.nomad.xyz/developers/environments.md): Interact with Nomad across testnet and mainnet environments
- [Domain (Chain) IDs](https://docs.nomad.xyz/developers/environments/domain-chain-ids.md)
- [Application Developers](https://docs.nomad.xyz/developers/application-developers.md)
- [Building xApps](https://docs.nomad.xyz/developers/application-developers/building-xapps.md)
- [SDK](https://docs.nomad.xyz/developers/application-developers/sdk.md)
- [Contracts SDK](https://docs.nomad.xyz/developers/application-developers/sdk/contracts-sdk.md)
- [Typescript SDK](https://docs.nomad.xyz/developers/application-developers/sdk/typescript-sdk.md)
- [Examples](https://docs.nomad.xyz/developers/application-developers/examples.md)
- [Ping Pong](https://docs.nomad.xyz/developers/application-developers/examples/ping-pong.md)
- [Advanced](https://docs.nomad.xyz/developers/application-developers/advanced.md)
- [Router Pattern](https://docs.nomad.xyz/developers/application-developers/advanced/router-pattern.md)
- [Node Operators](https://docs.nomad.xyz/developers/node-operators.md)
- [Running Agents Guide](https://docs.nomad.xyz/developers/node-operators/running-agents-guide.md)
- [Troubleshooting](https://docs.nomad.xyz/developers/node-operators/running-agents-guide/troubleshooting.md): Hints for dealing with common (and not so common) Agent failures.
- [Running a Watcher](https://docs.nomad.xyz/developers/node-operators/running-a-watcher.md)
- [Agent Operations](https://docs.nomad.xyz/developers/node-operators/agent-operations.md)
- [Agent Gas Values](https://docs.nomad.xyz/developers/node-operators/agent-gas-values.md)
- [The Keymaster](https://docs.nomad.xyz/developers/node-operators/the-keymaster.md)
- [Core Developers](https://docs.nomad.xyz/developers/core-developers.md)
- [Upgrade Setup](https://docs.nomad.xyz/developers/core-developers/upgrade-setup.md)
- [Deploying Contracts](https://docs.nomad.xyz/developers/core-developers/deploying-contracts.md)
- [Development](https://docs.nomad.xyz/developers/core-developers/deploying-contracts/development.md)
- [Production](https://docs.nomad.xyz/developers/core-developers/deploying-contracts/production.md)