Caller ID outfit Truecaller doubles user base to 20M in under 5 months

The Swedish caller ID and blocking service Truecaller, which has proven particularly big in India, has been around since 2009. However, the company’s growth has been particularly impressive of late.

Back in January we reported that Truecaller had amassed 10 million users. On Wednesday, the firm said it had hit 20 million – that’s twice as many users in just under 5 months.

Truecaller is effectively a huge, international reverse-lookup phone directory. Its data is derived from official phonebook services and also from users’ personal phonebooks, and is generally used to combat spam callers and telemarketers.

Last month, the firm opened up an API to let third-party developers tap into this resource, which was 600 million numbers strong at the time. “We’ve received more than a couple of thousands of requests, and we have some really cool cases that we are looking forward to closing soon,” a company spokesman told me this morning.

The spokesman added that, although growth is happening around the world, India was still the company’s biggest market, with the app having recently received a fair number of celebrity endorsements. Fair enough – I imagine famous actors and sportspeople must sometimes get a few annoying calls from strangers.