Meteor.startup(() => { if ( process.env.CORS ) { // Listen to incoming HTTP requests, can only be used on the server WebApp.rawConnectHandlers.use(function(req, res, next) { res.setHeader('Access-Control-Allow-Origin', process.env.CORS); return next(); }); } if ( process.env.CORS_ALLOW_HEADERS ) { WebApp.rawConnectHandlers.use(function(req, res, next) { res.setHeader('Access-Control-Allow-Headers', process.env.CORS_ALLOW_HEADERS); return next(); }); } if ( process.env.CORS_EXPOSE_HEADERS ) { WebApp.rawConnectHandlers.use(function(req, res, next) { res.setHeader('Access-Control-Expose-Headers', process.env.CORS_EXPOSE_HEADERS); return next(); }); } });