Japanese messaging app Line is going strong — it revealed today that it has now passed 400 million registered users. This means it has tacked on 100 million users in about five months, given that its total number of registered users exceeded 300 million in November last year.

Line 400m 1 Chat app Line passes 400 million registered users, inks record 10 billion messages sent in one day

Line notes that growing user numbers in countries such as North America and Europe have contributed to the “already large” user base in Spain and Southeast Asia among other territories. It also says that the number of new users signing up daily has reached “around 1.7 million per day, indicating rapid growth worldwide.”

Line’s home country of Japan counts the largest number of users, with 50 million, while Thailand and Indonesia come in next with 24 million and 20 million users respectively. India is also up-and-coming with 18 million users. Interestingly enough, it seems like the US has passed 10 million Line users as well — which could be due to the company’s plans for a renewed assault on the US market. WhatsApp’s outage in February could also be a contributing factor, as following its rival’s downtime, Line saw “record-breaking” growth in US and Europe.

However, as we noted before — the number of registered users on Line needs to be taken with a pinch of salt, as it double counts users who have one account but use Line on multiple devices. What’s more, despite clear evidence of traction, Line doesn’t provide active user numbers, so it’s tough to directly compare to bigger fish like WhatsApp (465 million monthly active users) or WeChat (355 million monthly active users).

Today, Line also announced a new record of 10 billion messages sent in a single day on March 21. Since the start of 2014, daily records have also been set for sticker messages, which passed 1.8 billion a day, as well as phone calls, which exceeded 12 million in a day.

Despite being a free app, it seems like Line has settled on a content-driven recipe for bringing in revenue. Line brought in 34.3 billion yen ($338 million) of revenue for its parent company throughout the whole year of 2013, with in-game purchases making up about 60 percent of revenue. That’s followed by sticker purchases, which account for 20 percent of revenue, as well as official accounts and sponsored stickers.

Line CEO Akira Morikawa says that one of its goals for 2014 was to reach over 500 million users. It seems like the messaging app is well on its way to surpass that target.