Data tracking websites have reported that the Threads app, launched by Instagram as a competitor to Twitter, has achieved over 100 million user sign-ups in less than five days.

This milestone smashes the record previously held by the AI tool ChatGPT for the fastest-growing consumer app. While ChatGPT took two months and TikTok took nine months to reach 100 million users, Instagram itself took two and a half years after its 2010 launch.

Threads became available on Apple and Android app stores in 100 countries on Wednesday, excluding Europe due to concerns from parent company Meta regarding compliance with the European Union’s data privacy legislation.

Twitter, in comparison, currently has approximately 200 million regular users, but it has been plagued by technical issues since Elon Musk acquired the platform last year and implemented layoffs.

Musk, also known as the CEO of Tesla and SpaceX, has faced backlash from users for introducing charges for previously free services and allowing banned right-wing accounts back onto the platform. Despite a few emerging competitors, most are niche platforms lacking the necessary scale to challenge Twitter’s dominance.

Threads, benefiting from its connection to Instagram, which boasts over one billion regular users, has found it relatively easier to attract users.

According to online data service Quiver Quantitative, the app surpassed 100 million users at 0700 GMT on Monday. However, other websites that track the “badges” received by Instagram users who have downloaded Threads believe the mark was reached earlier.

In a separate development, Musk has threatened legal action against Meta, accusing them of stealing trade secrets and intellectual property. Meta, the parent company of Facebook and WhatsApp, has denied these claims.

The rivalry between Musk and Meta chief Mark Zuckerberg has escalated to the point of public challenges, with both individuals recently calling each other out for a hypothetical cage fight.