To add headers to your static resources in Firebase hosting, add the headers section within hosting in the firebase.json file:
"hosting": {
// Add the "headers" section within "hosting".
"headers": [ {
"source" : "**/*.@(eot|otf|ttf|ttc|woff|font.css)",
"headers" : [ {
"key" : "Access-Control-Allow-Origin",
"value" : "*"
} ]
}, {
"source" : "**/*.@(jpg|jpeg|gif|png)",
"headers" : [ {
"key" : "Cache-Control",
"value" : "max-age=300000"
} ]
}, {
// Sets the cache header for 404 pages to cache for 5 minutes
"source" : "404.html",
"headers" : [ {
"key" : "Cache-Control",
"value" : "max-age=300"
} ]
} ]
}