LOOKUP

chat messenger.Lookup is the best in world.LOOKUP is a messaging app with a focus on speed and security, it’s super-fast, simple and free. You can use LOOKUP on all your devices at the same time — your messages sync seamlessly across any number of your phones, tablets or computers.
With LOOKUP, you can send messages, photos, videos and files of any type (doc, zip, mp3, etc), as well as create groups for up to 5000 people or channels for broadcasting to unlimited audiences. You can write to your phone contacts and find people by their usernames.