Deploying an Express app

Its settings

WORDPLUS_SITE, WORDPLUS_SECRET	from your app in WordPlus Cloud: the same on every server
WORDPLUS_LOCAL_KEY	yours: the same on every server, kept as long as the app

Keep the secret and the local key out of your repository and out of every page. The key reaches pages through realtime.config(), which is what it is for.

Its addresses

Add every address your pages are served from to the app in WordPlus Cloud: scheme, host and port exactly (https://shop.example.com, https://www.shop.example.com). A page anywhere else is refused with wrong_origin. Up to 20 addresses an app. If your server hears webhooks, set their address there too.

Its files

realtime-worker.js, realtime-rooms.min.js, realtime-rooms-e2ee.worker.js and realtime-ui.min.js are served by your app, from its own address: a browser runs a worker only from the page origin. Copy them in your build (postinstall), so each release serves the ones its package came with, and let them be cached like your other static files.

Behind a proxy

app.set( 'trust proxy', 1 );   // so the session cookie is Secure behind a TLS-terminating proxy
app.use( session( { /* … */ cookie: { secure: true, sameSite: 'lax' } } ) );

The routes need the session cookie: serve them from the address of the pages, as above.

Several servers

Nothing realtime is kept on your servers: any of them answers any request, and sending works from all of them. Only moving keys on keeps a little state, the generations, in a store they share (encryption).

Content Security Policy

If your pages send one, let them reach the WordPlus Cloud servers (the realtime servers, which may move a connection to another of them, and the media servers for group calls) and run the workers from your own address:

connect-src 'self' https://*.wordplus.cloud wss://*.wordplus.cloud;
worker-src 'self';

Clocks

Your server signs what it sends with the time. Keep its clock synced (NTP): one more than 5 minutes off has its emits refused with stale_signature.