Swap connection string on runtime EFCore

// ConfigureServices
var connectionStringProvider = new ConnectionStringProvider<WebApiDbContext>("ConnectionString");
services.AddSingleton(connectionStringProvider);
services.AddDbContext<WebApiDbContext>((s, o) => o.UseSqlite(
s.GetService<ConnectionStringProvider<WebApiDbContext>>().ConnectionString));



// Singleton provider for connection string (or other DbContextOptions)
public class ConnectionStringProvider<TContext> where TContext : DbContext
    {
        public string ConnectionString { get; set; }

        public ConnectionStringProvider(string connectionString)
        {
            this.ConnectionString = connectionString;
        }
    }
    
// Now you can just get the ConnectionStringProvider from your DI-Chain and swap the connection string at runtime,
// with effect at the next scope (request).