Grab Ate Everything
Remember when Southeast Asia had competition? Grab bought it all. Now Grab does rides, food delivery, package delivery, payments, hotel bookings, and probably your laundry.
The app is... fine? Not great. Search is weird. Sometimes shows restaurants that are closed. But it works in every city, every island, every random beach town where you made poor life choices.
Except When It Doesn't
Chiang Mai randomly loves Bolt for rides. Cheaper than Grab, way cheaper than taxis. But only for rides - Bolt doesn't do food here.
Bangkok's got Line Man for food delivery and honestly it's better than Grab Food. More restaurants, better promos, actually delivers to my weird soi that Grab drivers refuse to enter.
FoodPanda exists but I forgot about it until just now.
The BTS Rabbit Hole
You NEED the Rabbit Line Pay app for Bangkok's BTS (the skytrain). Except the app is garbage. Takes 5 tries to add money. Sometimes doesn't work at the gates. Everyone complains about it. Everyone still uses it because standing in line for paper tickets makes you feel like a tourist.
MRT has a different app. Because why would Bangkok have ONE system?
Grab also does payments now (GrabPay) and you'll accumulate points you'll never use.
Random Essential Stuff:
Google Translate with Thai downloaded because outside tourist zones nobody speaks English and that's totally fine but you need to read menus.
Klook for booking tours/activities - cheaper than booking direct, and yes I know that's weird.
Bolt for Chiang Mai rides specifically.
The Weird Part:
Bangkok taxi drivers will refuse your Grab ride and insist on meter. Except the meter runs 2x what Grab quoted. So you stand there like an idiot debating if $1.50 difference is worth the argument.
Motorcycle taxis (the orange vest guys) don't use apps in most places. They just exist at corners. You walk up, negotiate in broken Thai/English/hand gestures, you pay 30 baht ($0.85) to go 2km. It's faster than any app and no, it's not safe, yes you'll do it anyway.
Real Talk:
Download everything before you need it. You'll be standing in the rain trying to figure out which app works in this specific city while your phone dies.