Deploy .NET

.NET apps need the Starter plan or a bigger one. See pricing.

Detected by

a .csproj file at the top of the project. The general rules are in Deploying.

Build

• .NET 8 SDK: dotnet publish -c Release for the .csproj at the top (the first by name if there are several).
• The output runs on the ASP.NET Core 8 runtime as dotnet YourProject.dll.
• Put the web project's .csproj at the top of the zip; projects it references can sit in subfolders.

Start

Always dotnet YourProject.dll. ASP.NET Core is already told to listen on PORT, so you set nothing; don't hard-code UseUrls or a port in launchSettings.json-style code.

Example

using Npgsql;

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddNpgsqlDataSource(builder.Configuration["DATABASE_URL_NPGSQL"]!);
var app = builder.Build();

app.MapGet("/", () => new { ok = true });
app.MapGet("/orders", async (NpgsqlDataSource db) =>
{
    await using var cmd = db.CreateCommand("SELECT id, total FROM orders ORDER BY id DESC LIMIT 20");
    await using var r = await cmd.ExecuteReaderAsync();
    var rows = new List<object>();
    while (await r.ReadAsync()) rows.Add(new { id = r.GetInt64(0), total = r.GetDecimal(1) });
    return rows;
});
app.Run();

Frameworks

Good to know

• Configuration: environment variables override appsettings.json; use double underscores for sections, ConnectionStrings__Default for ConnectionStrings:Default.
• Behind our HTTPS proxy, add app.UseForwardedHeaders() with XForwardedProto so redirects and links use https.
• Npgsql wants its own connection-string format (Host=...;Port=5433;...;SSL Mode=Require); see Databases.