Can I get another 30-day visa exemption after a day trip to Vientiane from Nong Khai?

and I think now the O/P knows both what type of entry stamp they're getting in on when they show up here without a visa for thailand in their passport AND that they can get another 30 day visa exempt entry when they cross back into thailand from Lao at the Nong Khai border crossing.

Good Luck (y)

There are no 30 day tourist visas, you'll be getting a 30 days visa exemption and the answer to your question is yes.

long answer: yes

Short answer yes.