Truecaller, a Swedish company that runs a reverse-lookup phone directory so users can see who’s calling them, is particularly big in India. So it makes sense that that’s where the company is launching its new partnership with Twitter(s twtr).

The deal represents a handy bit of integration between the two services. When someone calls a Truecaller user in India, the app will tell them whether the caller’s number is associated with a Twitter account. They can then tweet at or follow the caller – however, this doesn’t make the Truecaller app a fully-fledged third-party Twitter client, as users can’t reply to tweets or see timelines.

As for how phone numbers are associated with Twitter accounts in the first place, Truecaller didn’t offer any explanation. However, it’s worth remembering that Twitter’s two-step authentication process involves registering a phone number, and also that carriers in many emerging markets offer low-cost…