Messaging app WhatsApp now has 500m active users, having added 70m since announcing in February that it was being bought by Facebook for $19bn.

“In the last few months, we’ve grown fastest in countries like Brazil, India, Mexico, and Russia, and our users are also sharing more than 700 million photos and 100 million videos every single day,” wrote WhatsApp chief executive Jan Koum in a blog post.

Koum provided more details in an interview with technology site Recode, claiming that WhatsApp has 48m active users in India and 45m in Brazil. “The message growth rate in Brazil — it’s not like a hockey stick, it’s like a vertical line,” he said.

He also took a potshot at rivals like Line and KakaoTalk, which have ambitions to expand globally from their strongholds in Asia.

“There’s not enough money and not enough celebrities in the world to convince people to use a shitty product,” said Koum. “People are so savvy these days. People expect a good user experience.”

WhatsApp has encountered a few gremlins on that front since the Facebook deal was announced, including a three and a half-hour outage that week in February and another early in April, the same day it announced record figures of handling 64bn messages in a 24-hour period.

Koum was referring to what he sees as “bloated” apps from rivals, which are adding games, shopping, music and other features to their core messaging functions. WhatsApp has focused on text, photos and videos, with plans to add voice calling by the summer.

This focus has driven startling growth for WhatsApp over the last year. In April 2013, the company had more than 200m active users, and was processing an average of 8bn inbound (sent) and 12bn outbound (received) messages a day – the difference comes from messages sent to multiple recipients.

WhatsApp reached 250m active users in June 2013, then 300m in August, when it was processing 11bn inbound and 20bn outbound messages a day, while users were sharing 325m photos a day.

By December 2013, WhatsApp had 400m active users, and now four months later it has 500m. At the start of April, the company tweeted that it had just processed 20bn inbound and 44bn outbound messages in a 24-hour period.

In short, WhatsApp has doubled its daily message and photo counts since August 2013, while adding 200m active users in that eight-month period.

Facebook is focused on further growth following its acquisition, though: “WhatsApp is on a path to connect 1bn people,” said its chief executive Mark Zuckerberg as he announced the deal in February.

“WhatsApp is the only widely used app we’ve ever seen that have more engagement in a higher percent of people using it daily than Facebook itself,” he added in a subsequent call with analysts. “Internet services that reach a billion people are all incredibly valuable, and we believe WhatsApp will be as well.”

It has taken WhatsApp five years to reach 500m users, as it first launched in early 2009. Facebook took just over six years to reach a similar milestone, having launched in February 2004 before surpassing 500m active users in July 2010.

Zuckerberg headlined his blog post on that milestone “500 Million Stories”, and Koum clearly took notice. When WhatsApp reached 400m active users in December 2013, its CEO chose to headline his blog post “400 Million Stories”. Two months later, the Facebook deal was announced.

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