As punter, it's unavoidable that you both get solicited and made solicitation via Wechat. Sadly, Wechat in Vietnam is usually fraught with scams and danger. Very occasionally will you find diamond in the rough experience. Among my band of punter bros (in VN), I'm acknowledged as the guru of Wechat love. Please allow me to share my findings for whatever it's worth to you.

1. Professional Wechat prostitution.

1a. Professional Wechat/Pimp Network.
Obvious Telltale Sign: One single photo that look too good to be true. No postings on timeline. Profile description (besides super obvious ones like massage/sex) such as; "lonely", "single", "find girls for you", "i need help", etc.

Less Obvious Signs: They actually have 1-2 months worth of timeline (where they will all the posts from Wechat "Hotgirls" (see their profile on down)).  

Usual Opening Dialogue: Where are you from (cuz they usually don't do locals)? What's your name? Where are you? Answers to those will quickly lead to "you want me to come over", "you want sex"

I usually just type "photo". Photos usually too good to be true. Hell, I see at least couple instances where they send photos of women I know (and wish they actually work...would pay many times more if it were so). I will also ask for video chat. They will usually say their phone can't video chat.

Usually you chat with the pimp. These minor pimps tend to have multiple numbers and profiles. I learned that there're usually 3-5 groups operating in D1.

These are the worst of all type and avoid at all cost.

PRO TIPS. I usually ask them to meet me at lobby. I NEVER give out my registered name nor room number. I tell them that if look different from photo, I will reject with no taxi fee (which they try to wrangle out of you to the tune of 100-200k!). Bottom line, they can't do a thing to you at hotel lobby especially since there are no transaction. They'll usually just slink off to their waiting pimp's motorbike. A lot of time they'll insist with straight face that their photo is photoshopped when you said "you don't look like photo"...thinking foreigners can't tell the difference. You can do this for all pro-girls from Wechat.

1b. Professional Wechat/Individual Network
All traits similar to Pimp Network. However, they chance of them looking like photo are better. These ones, some of them willing to video chat. This way you can actually see what they look like! They usually have couple friends they can refer you to if you don't like them. More often than not, they stay at 2 stars hotel (out of town girls) in pair or more.

Service-wise, it's usually hurried job. In-and-out.

PRO TIPS: I usually negotiate price to be 900k to 1 million VND short-time. Tell them I will give another 200-300k in tip if good service.

NEVER GO TO MOTEL OF THEIR CHOICE AS THEY GET ARE IN LEAGUE WITH MOTEL PROPRIETOR AND EVEN HAVE ACCESS TO LOCKER.

1c. Professional Wechat/Hostess Bar Girls.

These girls are usually mid-tier hostess at hostess lounge. They usually don't go home with customers. While top girls get good money, these mid-tier or lower income fluctuates. With crap economy, it's usually less. However, they need to keep up their appearance. Instead, they look to sell their wares to foreign visitors so it won't affect their standing as "no sex" hostess.

Telltale Signs: Usually have pretty long Timeline/Moment history in their Wechat. 2-6 months worth.

NOTE: These are the hardest to tell. I accidentally ran into two. I eventually found out because she so pissed at me grilling her (via Wechat) if she is who she is...that she said I could go meet her at her work. Of course, she was so indignant by my grilling that she said she will no longer have sex with me. Just drink as friend. Of course once I meet her, we eventually end up back in my place as friend with benefit (I get the sex she gets the money).

more to come on other type of Wechat Girls...

2. Non-Pro Wechat Women.

2a. Wechat/Hot-Girls.
Obvious Telltale Sign:
Long-ass and frequent Moment post. Not unusual to see multiple photos in a day. It's like their only job is selfie. Like most Vietnamese girls, dress to kill/reveal although classier. Usual backdrops; clubs, nice shopping places, travel, other beautiful people.

Less Obvious Signs:
Their posts tend to get a lot of engagements (Like, Comment)

Characteristics:
Accept your Friend Request so you can become one of their "followers." Flakey as hell. No real intention of chatting with you. If they reply at all, it'll be 1 to 2 reply the whole day if that.

Chance of hitting it:
Very slim. 5%. It's possible as I can personally attest but it takes a lot of creativity, perseverance and persistency.  My lifetime hit-rate here is exactly 1.

2b. Wechat/Wannabe Hot-Girls.
Obvious Telltale Sign:
Very similar to Hot-Girls except see below

Less Obvious Signs:
Their Moment posts tend to get between 0-2 engagement. Those 1-2 Likes either come from themselves liking their own post and/or their sister/roommate. No Likes from anyone else. Ever. Delusional - love to say shits like "Good night everyone" like they have audience of a thousand when they're just yapping to themselves (as seen on their engagement rate)

Characteristics:
Accept your Friend Request so you can become one of their "followers." With enough followers, they think they can ascend to the rank of real Hot-Girls and not just a wannabe. Flakey as hell. No real intention of chatting with you. If they reply at all, it'll be 1 to 2 reply the whole day if that.

Chance of hitting it:
Very slim. 10%. It's possible as I can personally attest but it takes a lot of creativity, perseverance and persistency. My lifetime hit-rate here is exactly 2.


2c. Wechat/Normal Girls aka The Unicorn
Obvious Telltale Sign:
Regular posts in Moment with combo of selfie and their life.

Characteristics:
Accept your Friend Request out of curiosity. If decide to meet you, depends on level of conversation, they will likely bring out their gf the first couple times to meet you. By the third date, if they still bring any sort of company, it's time to jump ship. If not, it's likely to go all the way soon than later.

Chance of hitting it:
Best of the bunch. 20%. But hard as hell to find these. Girlfriend material. I have a good fortune of getting together with 3-4 (and counting...1 latest this week to meet). Some of them semi-commercial (but reasonable). 1-2 of them very GF material and very non-commercial. Never even told me their stories about sick dad/mom/bro/sis/relatives/buffalo/plants/dogs. I had to break those off because I felt so bad knowing I was not in it for the longhaul. Yep, even the player have his moment of conscience.

2d. Wechat/The Transformer.
Obvious Telltale Sign:
Similar to the Unicorn. But more than meets the eye.

Characteristics:
Start to mistake your niceness for stupidity. Suddenly sees ATM sign appeared on your forehead. Start telling your their tale worthy of Greek tragedy with the usual cast of characters that ends up with one singular conclusion, they have sudden need of big money.

Conclusion:

I would avoid Wechat Professional types like a plague. Even in the smallest event where they are who they are, the chance of you getting even decent (forget about good) service is extremely small. There are just way too many downsides.

For 1 million a pop that these Wechat Pros are asking for, you can find local FS barbershop in D10 area. Just do your research here. At least you get to choose the ones you like. While service will still be spotty, the chance of getting decent to good service still way higher than Wechat Pros.

Of course if you follow my reports, you know that I tend to favour KTV girls although that can get expensive with 1 person outing.

But if you got lucky and engaged one of the  Wechat Non-pro type, go for it. I forgot to mention that some of those non-pro can end up expecting some sort of financial assistant along the way especially if they come from not so stable economic background (which would be most of them sadly).

Got drunk in Saigon, WeChat'd some girls, spent $150 USD for short time. I was rudely interrupted by hotel calling me saying that the girl couldn't stay there (which she did anyway, and they never followed up) which was off putting to be thinking about wondering if they were gonna knock on my door mid BJ. CBJ, rushed, terrible service.

TL;DR - WeChat is not the go to for working girls, unless you find a unicorn, and drinking + horny = paying over what you should be paying for in USD (which should be around $40-$60 USD).

For what it's worth, I was there for a few days I had good luck with some girls in the "unicorn" category. I explicitly avoided the professionals based on your advice. I found that you can pretty much just ask "are you a massage girl" and then respond based on their answer. The normal girls will be offended, but not surprised.

My advice if you're going for normals is to WeChat outside of D1 and try to iniate during business hours to catch them at work. Other than that, it's like picking up non-WGs anywhere. I chatted for a few minutes at a time a couple of days in a row and then set up a meet for coffee or drinks. It's downhill from there. It seems that if they're making posts in English, they are eager to meet foreigners.

A word of warning though. Some of these girls are very naive and inexperienced. Try not to take advantage of them. If not for empathetical reasons, then because you're risking some serious attachment issues.