VOIP has matured a lot since it first came about. It offers cheap international calls, as well as dirt cheap domestic calls. Skype has become synonymous for VOIP calling, but there are now an abundance of mobile apps that offer the same service that are also free. My list that I will go over will contain apps that require both the initiator and receiver to have the specified app (with the exception of Skype that can make calls to ordinary numbers if you pay). I wanted to share my experience with some and how they compare.
All my testing was done on WiFi with a maximum download speed of 4Mb/s and an upload speed of 1MB/s, which is both throttled and capped. My calls were made from varying locations including the US, the Dominican Republic, Singapore, Vietnam, and Indonesia. All tests were done on my LG G3 phone using Android 5.0 (Lollipop).
Viber has been around a long time and was one of the first of the apps I will be discussing to have VOIP integrated as part of its service.
Viber requires a phone number to setup, but once done, you can use any number with that smartphone and still retain Viber. A message ID can also be messaged to the number you wish to validate if you are not currently using that number on the phone being used or are having problems with the automatic detecting of your number on that phone.
Viber has a slick interface filled with purple and gray. It also offers messaging with stickers for the modernized touch in communication. Viber takes about 70 megabytes of space.
The call quality is the best I have experienced. As long as the connection on both ends are stable, calls are void of static. People on the other end are loud enough where you can make out background noises at times, but not enough to detract from the caller's voice.
Google Hangouts is still fairly new, but Google has promised to continue updating and upgrading it. It received the ability to VOIP in 2014.
Setup for Hangouts is really simple if you already have a Google account. You login with your Google account credentials and you're done. If you don't have a Gmail or Google account, you will need to set one up beforehand. Hangouts takes about 44 megabytes of space.
Hangouts is mostly green and gray. It is very simplistic (which may change once new revisions are made), and is also an app messenger that includes plenty of emojis, and as of recently, stickers.
Hangouts rivals my experience with Viber. While I still put Viber slightly higher than Hangouts, I should mention that I have got better reception with Hangouts than with normal calls. Static can still be abundant if on the move, but the call never seems to drop if you wait for the static to die off. People on the other end are very clear and loud, I notice no background noises if not put on speakerphone.
I also wanted to mention that I did not review the Google Voice app because now it just integrates with Hangouts.
WhatsApp is another (popular) messaging service that has since integrated VOIP into its services. Another interesting point is that it was bought by Facebook, which I only bring up because I will also review Facebook Messenger's VOIP capabilities.
Setting up WhatsApp is identical to Viber. Just plug in your number and wait for your phone to tell you it has been verified. WhatsApp takes about 38 megabytes of space.
The color scheme of WhatsApp is probably the best I have come across (the UI was recently updated, but the colors remain the same). It contains dark green, and the actual messaging portion shows a light beige background which is very easy on the eyes. As with all the other apps, it too has emojis, but no stickers at present.
WhatsApp is my favorite messaging app, but is the worst experience I have had with VOIP apps to date. I tried it a few times and it was near impossible to talk with all the static, dropped portions of the call, and seconds of lag. I had really hoped it would be a winner as I did have some contacts on WhatsApp that might find this useful from time-to-time. I did receive a call through WhatsApp while in the same country as the caller. The call quality was on par with Facebook, however, the call kept dropping and reconnecting. It is definitely the one to pass up if looking for free VOIP options.
VOIP on Facebook Messenger only came out a couple weeks ago. As such, things may change in the future, hopefully, only for the better.
If you don't have a Facebook account you're either old or weird. Even I have one, although I almost never use it anymore. Anyways, you need a Facebook login to access the app's features, which requires an email for signup. Facebook Messenger (different from the Facebook app) takes about 78 megabytes of space.
Facebook Messenger sticks with their classic colors of blue and white. It has emojis, stickers, and even voice message capabilities. Yet, all these items make it seem a bit cluttered at times.
Facebook Messenger has excellent call quality. There was no noises in the background, and while not as audible as say Viber or Hangouts, still perfectly loud enough for a call. The only thing I noticed was an approximate one-second lag that was quite bearable. The odd thing to me about this experience is how far off it is compared to my WhatsApp experience considering both are owned by Facebook...
Blackberry Messenger (BBM) has had VOIP integrated since before it was released for iOS and Android devices. I don't believe a lot of people even realize it has this function, but it has remained part of its services nonetheless.
BBM requires a BBM account to use its app. You only need a valid email address. After that, people can use your designated BBM pin to add you, or a special QR code. BBM takes about 51 megabytes of space.
BBM uses blue and gray, as well as a bit of black. It doesn't seem to have stickers, but all the usual items are available.
BBM places around third or fourth on my ranking of VOIP services. When it was first featured it was horrible, but then again it was only for Blackberrys, and I never tried it on Blackberry OS 10. In any case, on two Android devices, it works wonderfully. There is a tiny bit of lag that is unnoticeable unless you are literally in the same room with the caller.
Skype is what made VOIP a household name. I know numerous people who still don't realize that Skype is VOIP and not the other way around. They have cemented their status as a VOIP service, but more for video calls than just calls.
As with some of the others listed, Skype requires an email to signup. However, an email or user ID can be used to login to your Skype account. Skype takes about 93 megabytes of space.
Skype uses the traditional blue and white. It doesn't have a feature-rich messenger, but that was never the point of it. It does have a slightly different UI than the rest, but it is refreshing.
Skype isn't the best on calls, but its certainly not the worst. I would say I would normally get decent reception, but a lot of followed static that can only be described as edging on the voice of the recipient as opposed to being in the background. Recently I found that the beginning of the call will be bearable, but after so long it would become almost impossible to pick up the words of the recipient. If you have WhatsApp, this would be an upgrade, but I wouldn't use it for VOIP otherwise.
BONUS: Talkatone & Spare Phone
I have mentioned these two apps in the past, and the reasons I am not considering as part of my official list is: A) They are (were) meant to be used in conjunction with Google Voice and a valid Google number, B) which means you would just dial phone numbers not just people who have the same app.
Talkatone was my first app I used with my Google number. I initially used it on an iPhone, and then later an Android. The free version comes with advertisements. I never purchased the paid version as the free version was satisfactory.
Talkatone takes about 21 megabytes of space.
In all honesty, while I made a lot of calls with this app, it was pretty horrible. I would get dropped calls, echoes, or people just couldn't hear me. It's a wonder I ever stuck with it, but it is still available today.
Spare phone is my app of choice on my Android. It is not available for iOS devices. It is a paid app, but it is of great quality.
Spare Phone takes about 1 megabyte of space!
Calls on Spare Phone are quite clear. The only complaint I ever get is that it sometimes creates echoes and it can give lag. The app itself may shuts down calls after an hour, or just bugs out by disallowing calls. Part of this may be because I use an older version. Unfortunately, it seems that newer versions have changed to act more like the apps listed in that you don't call phone numbers but other people who also have the app...
How They Chalk Up
The app for you may depend on what is popular in your area, or what most of your contacts use. If going for the best call quality, I would say Viber fits the bill. If going for the best quality with the least amount of space, then Hangouts might work best. More than likely, if you wanted something everyone already has instant access to, Facebook Messenger might be the way to go. In terms US calls for a purely VOIP app, then Spare Phone is a no-brainer!
There are other apps out there, but I just wanted to touch on a few of the most popular where chances are you already have at least one that I've mentioned.