Yes, You Can Run a Real SQL Database Directly Inside dotnetfiddle.net

You can run a real SQL database inside dotnetfiddle.net, entirely in RAM, with zero setup. No server, no file, no teardown.

SQLite in-memory gives you a full relational database that lives and dies with your connection. It’s perfect for prototyping queries, testing schema ideas, or proving to a skeptical coworker that SQL actually works the way you think it does.

SQLite introduced in-memory mode back in version 3.0 (2004) - all the SQL power, none of the I/O overhead. dotnetfiddle.net even ships a dedicated template for it.

var connection = new SqliteConnection(”Data Source=:memory:”); // <<< no file - entire DB lives in RAM
connection.Open();

var create = connection.CreateCommand();
create.CommandText = “CREATE TABLE Devs (Name TEXT, CoffeeOrder TEXT)”;
create.ExecuteNonQuery();

Try it yourself (no setup required): https://dotnetfiddle.net/5v8UVU