Truecaller has added flash messaging support to its iOS and Android apps.
With flash messaging, you don't have to type long messages for simple queries or yes and no answers. In your Truecaller contact list you will see a lightning bolt icon next to people using Truecaller. Tap on it and you get a bunch of commonly used emoji and frequent queries and phrases like "Where are you?" and "On my way!". There is also a button to send your location. You can tap any of these to quickly send them to your recipient. Alternatively, there is an option to type out a short message.
The person receiving the message gets the message flashed on their screen. From there they get the same options as before to quickly reply back with minimal taps.
Flash messaging is not a replacement to traditional IM or SMS messaging but rather a way to get to someone in a jiffy without typing out long messages. On Android, the incoming message also takes up your entire screen like a call would so it's hard to miss. Ideal for emergencies or when elaborate conversation isn't possible, like during a meeting.