Well, thats not a fair comparison. A key aspect of valuation here is governed by Gross Margins. Infobip and a lot of the companies mentioned below on this thread have gross margins in the early to mid twenties in contrast to Twilio, which is in the early fifties and thats one major reason for the difference in valuation. The other is growth % YoY.
Disclosure: I am the co-founder of https://www.plivo.com/, a startup in the same space.