Y Combinator and Start Fund-backed startup SendHub, which offers a simple SMS solution for businesses, is killing it…and it never “officially” launched. Instead, the company soft-launched a couple of months ago with zero fanfare, and already has several hundred customers, 40% of which are active monthly users, sending some 30,000 SMS text messages per month.

Although generating revenue through its premium services for businesses, SendHub is also making teachers’ lives easier, by providing them with free tools to communicate with students and parents via SMS.

The big draw for SendHub has nothing to do with buzzwords (aren’t you sick of local, social, photo-sharing apps, anyway?), and everything to do with building something people actually need: an affordable, easy-to-use alternative to today’s business-focused messaging platforms. In January, the startup grew its user base by 3x, and so far this month, it’s grown another 45%.