Because I am a late adopter of technology and because of the fact that this entire country is a late adopter of technology would you believe that I actually had no idea that you can order just whatever on Amazon until about 5 years ago? I was still living in the bubble of them selling books and DVD's. I feel like a real idiot sometimes.
Anyway, this isn't about them. It is about Lazada, which is an absolute must if you are an expat living in Thailand.

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I say it is just as good as Amazon with a question mark because there is no way that it offers as many services as Amazon but while you CAN use Amazon in this country even Amazon suggests that you don't use it. Here's why.
If something is coming from overseas there is an unfortunate tendency on the part of Thai Customs to be jerk-faces. They will slap an absurd import tariff on something (often at a higher cost than the item itself) and these sums they come up with are based on nothing at all, it is definitely outright theft. Other times packages simply don't arrive at all indicating that customs saw something, and just decided to keep it for themselves.

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suffice to say, you should try to avoid having to deal with these guys
Things have improved a bit in the past couple of years and many would argue that it is because the military leaders of the country that exist right now are considerably more "no-nonsense" and less inclined to allow corruption. I don't know, this is another story altogether and one that I am not knowledgeable enough to comment properly on.
Lazada is easy to install just like any other app on the play store and just like Amazon, once you get one thing successfully delivered to your apartment or house, all the rest of them are going to be just as easy. I say "successfully delivered" because the addresses in this country are convoluted and difficult, but most of the time parcel delivery companies can get past this.
Unless you can speak Thai as well as I can (and you likely don't) it can be very difficult to explain to a shop clerk about some particular thing you are looking for. For example a set top box for playing Netflix on non smart TV's or perhaps a food processor like a Cuisinart. You can spend all day bumbling through a conversation with a clerk who likely doesn't know how to help you anyway, or you can have the thing ordered on Lazada in minutes (and probably at a cheaper price too.)
Their interface by default is in Thai, but they make it easy enough to find the language settings in the app because Lazada is actually a Chinese company anyway.

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Just like any online ordering company (there is probably a better name for it than that) they have both mobile and pc interfaces, and both of them work wonderfully. They don't yet have any feature like groceries but to be honest with you I wouldn't want my food to be delivered to me anyway as most of the trucks in this country are not refrigerated.
TL;DR
Lazada is a must-have app for anyone living in Thailand for more than a month or so. You don't even need to have a credit card for the most part because you can pay at 7-11 or even C.O.D. in many cases. It eliminates the language barrier and makes the finding of difficult items easy. I use it regularly even though I can speak Thai and therefore I would say anyone living here will make their lives easier by using it.