It really depends on what he texted.
If he texted you telling you about how much fun he had on the date and asks you about when next you would be available to go on another date, he is interested.
This shows that he is willing to take the next step.
He is not just commenting, he is actually trying to take decisive action to see you again.
If he texted you after the first date and asks you to further elaborate about something you were talking about on the date, he is essentially keeping the conversation going.
He is showing you that he was paying attention to the conversation that was had and he would like to continue it.
He is probably still experiencing the after effects of the first date and he may not have wanted it to end.
A text like this shows that he is interested.
He is trying to keep the conversation going in order to extend the first date to some extent in his mind and to also let you know that he was paying attention to what was being discussed.
Thereby, it is important for him to show you that he was present.
This is a guy who is more than likely trying to impress and score some favorable points.
If he texted you asking you if you enjoyed the date and is self-deprecating, he is interested.
He cares about whether you had a good time and he may be playing down his charm.
He may be self-deprecating by saying something along the lines of, “Hope I wasn’t too crazy for you lol.”
Something along those lines would show that he does care about what you thought about him during the date.
So, in this scenario, he cares about whether you had a good time and what kind of impression he left with you.
Now, if he texted you after the first date with a very short statement that didn’t leave much room for a conversation, that would not be a good sign.
For example, if he texted a message that read something like this, “Enjoy the rest of your day/night.”
If he leaves it at that, this is not a good sign that he really enjoyed the date.
He may be trying to be polite.
However, you notice here that he didn’t try to set up another date with you nor try to keep the conversation going by addressing something that you had both been talking about during the date.
He is also not trying to gauge just how much you enjoyed the date or not.
He is not trying to be self-deprecating in any way to try to show humility.
He just texted a statement and left it at that.
This is not a very strong sign that he is interested.
Also, if he texted you a message that was only one or two words long.
This is not a good sign of interest either.
Something like, “Take care,” or “Good night,” are not very promising. Too short.
He may have already forgotten about you and is moving on.