[rl3]

I second this, it sounds cringey on the face of it. Maybe it works for non-technical customers, but I imagine technical customers would immediately be taken aback.

The only exceptions might be cases where very specific behaviors or implementation details are in question.

[scoobilydoobily]

My main issue here is that we have a technical product, and the people we are selling to are developers.

If they could build it themselves, they wouldn't be talking to us, but my co-founder doesn't seem to get this.

It reminds me of this Silicon Valley scene - https://www.youtube.com/watch?v=JlwwVuSUUfc

[LifeQuestioner]

Hmmm...The evidence is: he's made one sale. Any person can talk the talk. He's clearly doing things a salesperson shouldn't be. You, a non-salesperson know this. But perhaps he will shine through when the product is released. But to iterate, thus far, he has made one sale, that doesn't make you a salesperson. Yet.

He may be showing people the code because he's proud of it...

Speak to him.