You can't test it for free
This is the most common pattern for scammy dating apps. You will see that girls look at your profile, like you, send messages to you, but you need to pay to contact any of them. If a dating site doesn't let you reach any user for free, it's safe to assume some part of it is a scam, may hide a minimal amount of users or no real users at all, or it's overpriced for the number of users it is offering. Keep in mind that it's not very likely most of the users will have paid account. If you cannot contact users for free, even with Premium, many women cannot answer your messages because of their free account limitations. Examples are sites like eDarling or be2.
Pay for a message sent or by a minute of video chatting
I don't know any legit video cam chat with pricing per minute of conversation. I suspect such sites hire women for chatting and pay them for the minutes of video conversation. It's easy to share the percent of the income with the women. If she can lure the men into chatting more, she will get more money, so she has more motivation to be seducing. CooMeet (www.coomeet.com), for example, mentioned in the terms and conditions that girls can make money on chatting with guys.
Messages from beautiful girls
If we have an average profile with a simple selfie and do description, and the women who look like models want to chat with us, something is wrong here. It may be a scammer who works on his own, or the app is using fake profiles to lure people into buying Premium.
An attractive girl will never write first to men with average photos and no information. She may answer his catchy message but will not write to him first. Some sites will bombard the guy with messages from Girls even he doesn't have a photo. The girls don't need to be stunningly beautiful to assume to date app is not legit. If too many women want to chat with us and on different dating sites we don't have much interest in, this should already be a big red flag.
If you login to myDates (www.mydates.com) or iDates, for example, within a month, your inbox will have more than 100 messages from girls wanting to meet you, which obviously is too good to be true.
Hidden info about automatic subscription renewal
Using automatics renewal is standard in most dating sites (Tinder, Bumble, Hinge). Even outside the dating industry, many apps use this system (Spotify, Netflix). However, many dating companies try to hide this information with tiny grey letters. Later, the unaware user stop using the sites because it sucks, forget about the site, and later found out that his subscription renews for another six months and without promotion price. If he wants to cancel, he finds out the dating site administrators made it very hard to cancel. If the user blocks his credit card to stop losing money, it may become dark and ugly because the dating company may send him threats from the debt collection agency.
Read the c Date (www.c-date.com) review as an example of such a site.
Personality test
To create an account, you need to fill in 15 min personality test, and later it turns out you cannot contact anyone for free. You get plenty of messages "This woman is interested in you" send her a message, and when you try to contact her, you are redirected to the payment site. Not every personality test site is a scam. Still, many of them use this strategy to hide the fact they have a minimal number of users, so their recommendation is not based on the personality match but on the number of users they can offer.
An example of such a site is EliteSingles (www.Elitesingles.com), where many people complain that it's costly compared to a few users and recommended random people rather than based on the test they spend a lot of time filling in.
Administrators don't remove scammers
Romance scammers are people who pretend to fall in love with a man and later ask for money for a flight ticket or any other reason. When a girl from the internet asks for money, it always safe to assume it is a scam.
However, those scammers do a pretty good job in seducing men who can lure guys into buying Premium and chatting with other men. So some evil dating sites keep them despite the fact they scam the users as for dating site owner it's a win-win solution- dating app makes money on users buying Premium lured by scammers. Scammers made money by asking for money for a flight ticket.
Your experience?
Which online dating sites or date apps were you using? Are any of those seem to be fake? Or can you recommend the one?