As a result of Meta’s fast-growing rival app Threads, Twitter is considering taking legal action against it.

A “friendly” alternative to Twitter has been pitched by Meta bosses as Threads, which was launched to millions on Wednesday.

Elon Musk said “competition is fine, cheating is not” – but Meta denied claims that ex-Twitter employees helped create Threads in legal documents.

According to Meta, the new app has been downloaded more than 30 million times.

Twitter has an estimated 350 million users, according to Statista, which is less than a tenth of the total.

In 2013, Twitter took four years to build the same amount of users that Threads gained in a day, but Twitter grew its user base from scratch, while Threads leveraged Instagram’s two billion monthly users.

BBC News technology reporter James Clayton noted that Threads have a similar look and feel to Twitter. It was “incredibly familiar” to him to see the news feed and to see the repostings.

However, US copyright law does not protect ideas, so Twitter would have to prove that its own intellectual property, such as programming code, was violated in order to succeed in court.

The system that displays all the latest posts on Facebook was patent-protected by Meta in 2012.

According to Semafor, Twitter attorney Alex Spiro sent a letter on Wednesday accusing Meta of “systematic, willful, and unlawful misappropriation of Twitter’s trade secrets and other intellectual property” to create threads.

Spiro alleged Meta hired dozens of Twitter employees who “had and continue to have access to Twitter’s trade secrets and other highly confidential information” with the goal of developing what he called a “copycat” Threads app.

Twitter intends to strictly enforce its intellectual property rights, and the letter demands that Meta stop using Twitter trade secrets or other highly confidential information immediately.

Among its rights are to seek injunctive relief and civil remedies without further notice, including, but not limited to, civil remedies.

Meta and Twitter have been contacted by BBC News regarding the letter.

In response to a tweet about the legal letter, Mr Musk said, “competition is great, cheating is not.”.

Andy Stone, a spokesperson for Meta, wrote on Threads that “it just isn’t the case that any member of the Threads engineering team was formerly a Twitter employee”.

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For existing Instagram advertisers who “feel they can allocate some budget and see what happens,” Sarah Kunst, managing director at venture capital firm Cleo Capital, told BBC’s Today programme threads could offer a “brand-safe environment”.

While 30 million users could be the result of an initial rush, the app will likely see its user base steadily grow in the coming years.

According to her, the platform has made cross-posting to other platforms like Instagram very easy, so growth is likely to continue.

Musk and Zuckerberg acknowledge their rivalry over Threads, which is connected to Instagram but works independently.

A highly popular meme depicting two close-to-identical Spider-Man figures pointing at one another, indicating a stand-off, was posted by Mr Zuckerberg on Twitter as the company launched in 100 countries.

After the word “Threads” trended worldwide on his platform, Mr Musk remarked: “I prefer to be attacked by strangers on Twitter than indulge in hide-the-pain Instagram.”