| name | xprem-configure-expo |
| description | Wire an Expo app to a running xprem server. Use when the user needs the signing certificate (certs/certificate.pem), App ID, npx eoas init, updates.url / request headers, or a release channel on a native build. Not for publishing an update (use xprem-publish). |
xprem-configure-expo
Before you start
Read the live docs. Do not invent config keys, header names, or CLI prompts.
- Query the xprem-docs MCP (
https://mercure-technologies.gitbook.io/xprem/~gitbook/mcp), or
- Fetch Configure your application and Quickstart steps 5–8 at quickstart.md.
xprem is not affiliated with Expo. Use eoas, not EAS Update.
When to use
- A control-plane server is already running (see xprem-quickstart) and the Expo project is not wired yet
- Missing
certs/certificate.pem
- Need the dashboard App ID,
updates.url (server BASE_URL), channel, or npx eoas init
Steps (confirm every prompt on the live pages)
1. Create the app and copy the App ID
Open {SERVER_URL}/dashboard, create the app, then App Info and copy the App ID (UUID).
2. Download the signing certificate
App Info → Download certificate. Save it in the Expo project as certs/certificate.pem:
mkdir -p certs
mv ~/Downloads/app-<your-app-id>-certificate.txt certs/certificate.pem
Commit the certificate. The app uses it to verify that updates came from this server.
3. Create an API key
Dashboard → API tokens. Copy it now; it cannot be shown again. xprem-publish uses it as EOO_TOKEN.
4. npx eoas init
From the Expo project root:
npx eoas init
Prompts on the live docs:
| Prompt | Answer |
|---|
| Project id (sent as expo-app-id the in the header) | Dashboard app UUID |
| URL of your update server | Server BASE_URL — this is updates.url |
| Do you have already generated your certificates | Yes (downloaded above) |
eoas init also adds three keys to updates.requestHeaders: expo-channel-name, expo-app-id, and xprem-branch. Keep all three — expo-updates only sends headers declared at build time, and xprem-branch is what makes branch surfing possible. Keep expo-channel-name as a literal string, not process.env; the config is evaluated at export time and an unset variable silently drops the key.
5. Channel
Each native build is bound to a release channel. After the first publish, create a channel in the dashboard and attach it to the branch. Use the channel name that will be baked into the Expo build. Confirm on the live pages rather than assuming production.
6. Native rebuild
Server URL and signing certificate are embedded at build time. Existing binaries keep the old configuration. A new native build is required after this wiring.
Do not walk through publish here — hand off to xprem-publish.
