It is possible to get file-based routing working on the community Vercel Functions PHP runtime.
You simply need the following configuration:
vercel.json
{
"functions": {
"api/*.php": {
"runtime": "[email protected]"
}
},
"routes": [{ "src": "/(.*)", "dest": "/api/$1" }]
}
And, make sure to place all your PHP files under /api.