Hi @webrender,
try to replace the start script in package.json with next dev. Let me know if it works now 
EDIT: probably the project also need a couple additional changes. Try also adding a file called watch.json with this content:
{
"install": {
"include": [
"^package\\.json$"
],
"exclude": []
},
"restart": {
"include": [
"^\\.env$"
],
"exclude": []
},
"noSavedEvents": true
}
This tells Glitch to not restart the next server after an edit, so that next dev can recompile your changes more quickly, and also refresh the webpage for you 