Client apps are open source, making whole service more trustworthy.

There are native desktop, mobile and web client apps, that are optimized for speed and are light on memory usage.

Broadcasting channels suitable for announcing things.

The official telegram client will always be the best . Of course they will the first to update the new features . others have to wait for more than 2 weeks. Official telegram are almost completely bug free. Will receive support from telegram volunteers, and the installation files will always be lightweight compared to other clients.

Works on Windows, Mac, Linux, Android iOS, Windows Phone, and Firefox OS even. Has a web app that changes it's appearance based on the device it's running on and if it's browser is full screen, etc.

The application is available free of cost.

You can ping people to get their attention by @mentioning them.

Telegram uses an open source MTProto encryption protocol that provides complete end-to-end encryption for secret chats. To show off their confidence in the protocol the company behind Telegram has organized $200,000 and $300,000 challenges to break the encryption. So far there have been no winners.

Copy/paste videos, gifs, images, geolocation, documents, and even executable files. Drag over files for practically any time up to 1.5GB in size. Images can be compressed, too.

In addition to the end-to-end encryption that provides privacy to communications, the app also includes self destructing timers for chats, and the ability to permanently delete messages, yours and theirs, from your device.

Uses the latest GPL audio codecs, such as Opus, an adaptative high-quality codec that supersedes AAC at any bitrate.

In Supergroups, anyone along with admins can delete their messages from all sides. A message can be pinned to the top. All of the user's messages can be deleted by an administrator, and they can be banned and reported as well. Supergroups can have a public link (outside of Asia, due to high spam volumes), which is also a username.

Very customizable with a lot of clean looking options.

The desktop app has a built in setting to scale the UI of the app up to 200% which allows for those with 4k monitors/screens to use the app without scaling issues.

Messages can be set on a timer. They will disappear after the timer expires.

On SimilarWeb you can see that Telegram is on the top 15 among all communication apps.

You can pin messages to the top of groups or supergroups so members will see them when opening the group.

Although it's volunteer based, but still pretty top-notch if available, which it tends to be.

You can post voice and video messages if you are too lazy to write text messages.

You can set up an additional password to your account, which can be reset by your email. You don't have to use an email if you do not want to. If you lose access to your email or forget your password, you will be able to reset it via text message if your account is over seven days old and will receive it within a week (in case you recover anything before then).

You can pin messages to the top of groups or supergroups so members will see them when opening the group.

Even though encryption used for cloud-based storage (e.g. Gmail, Facebook, iCloud) may not be as secure as end-to-end encryption or zero-knowledge storage, Telegram does the most that it can by holding keys to chats in different jurisdictions, requiring intergovernmental cooperation to obtain the keys. This is aside from whatever other security measures have been taken, of course.

Unfortunately, on the desktop videos don't play, but images are viewable without visiting popular websites like imgur and Instagram.

You can play YouTube videos and others within the app, so you don't need to embed code or anything.

With inline bots, such as @gif, @pic/bing, @vid/YouTube, etc, you can look things up without leaving the client or chat that you're in. Simply type the name and some keywords and wait for the results to load.

Videos, gifs, images, geolocation, and documents.

Unlimited number of files can be stored forever on the cloud. You can upload files up to 1.5 GB each.

You can write messages to yourself. You can write some notes, add links, and see everything across all your devices.