> For the complete documentation index, see [llms.txt](https://docs.vea.ninja/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.vea.ninja/build-xchain-dapps/lightbulb-demo.md).

# Lightbulb Demo

https\://lightbulb-vea.vercel.app

The lightbulb [demo](https://lightbulb-vea.vercel.app/) demonstrates a simple dapp integrated with Vea. The switch lives on Arbitrum Sepolia and the Lightbulb lives on a different chain, either Chiado or Sepolia, and they communicate with Vea.

[Try it out](https://lightbulb-vea.vercel.app/)!

## User flow

### 1. Hit The Switch (Arbitrum Sepolia)

<figure><img src="https://2506823371-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FCngnZjkdxdaNW3B4P5QC%2Fuploads%2FkeiDWlhauRC4LFhn3sNu%2FScreenshot%202025-12-29%20at%206.30.54%E2%80%AFPM.png?alt=media&amp;token=fc12fb18-577c-4e81-9753-2b2f1efdf4dd" alt=""><figcaption></figcaption></figure>

### 2. Wait for Vea

<figure><img src="https://2506823371-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FCngnZjkdxdaNW3B4P5QC%2Fuploads%2FYuTypoehnNqmRXzv76Yh%2FScreenshot%202025-12-29%20at%206.35.40%E2%80%AFPM.png?alt=media&amp;token=2d6499a8-0a9e-442b-985d-ed655109a980" alt=""><figcaption></figcaption></figure>

The status of the Vea bridging process and whether your messages have been bridged can be tracked in [VeaScan](https://veascan.io/). You can find the messageId associated with the switch transaction in the event log.

<figure><img src="https://2506823371-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FCngnZjkdxdaNW3B4P5QC%2Fuploads%2FtQYeQWrvUmLKmcZm87nk%2Fimage.png?alt=media&amp;token=3a97c115-23b1-4bf3-bc54-6fd4e62ef300" alt="" width="563"><figcaption><p>Switch Transaction event log</p></figcaption></figure>

When the Vea testnet has bridged your message, you can find your message in a recently bridged 'snapshot'.

<figure><img src="https://2506823371-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FCngnZjkdxdaNW3B4P5QC%2Fuploads%2FQoS5TKFzjLB82WcZZEu5%2Fimage.png?alt=media&amp;token=2a353a74-f7b8-41f6-a58e-a956b156684f" alt="" width="563"><figcaption><p>VeaScan successfully bridged message.</p></figcaption></figure>

### 3. Wait For Relayers

Now that the message to turn on the lightbulb is ready, we can relay it manually, or we can wait for relayers.

## The Final Result

<figure><img src="https://2506823371-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FCngnZjkdxdaNW3B4P5QC%2Fuploads%2FjkLsKLetNftMlzjxrZux%2FScreenshot%202025-12-29%20at%206.36.53%E2%80%AFPM.png?alt=media&amp;token=84a38fdc-09d0-4169-b846-ee09db559e8a" alt=""><figcaption></figcaption></figure>