TIOBE Programming Index News September 2025: Perl Regains the Spotlight

Last month, Perl’s gradual rise over the summer into the top 10 rankings was a bit of a mystery. Specifically, version 5 of Perl rose from 27th place last year to 10th place this month. It is still not entirely clear why the programming language from 1995 has garnered so much attention.

The TIOBE Programming Community Index measures trends in programming languages based on search engine volume.

Perl 5 publications proliferate

One reason why Perl rose in the leaderboard is a fascinating look at how the TIOBE Index works.

The Index judges programming languages by popularity or attention: it tracks the number of skilled engineers worldwide, courses, and third-party vendors related to each programming language as counted on Google, Amazon, Wikipedia, Bing, and other search engines and large platforms.

“The technical reason why Perl is rated this high is because of its huge number of books on Amazon,” said TIOBE Software CEO Paul Jansen in the index. “It has 4 times more books listed than for instance PHP, or 7 times more books than Rust. The underlying ‘real’ reason for Perl’s increase of popularity is unknown to me.”

The Perl on the leaderboard is the fifth version of Perl, and the second-most recent version.

“The only possibility I can think of is that Perl 5 is now gradually considered to become the real Perl,” Jansen said.

Perl 5 rises while Perl 6 lags

Perl 6, also known as Raku, ranks 129th on the leaderboard. For decades after Perl 6 was announced, development of Perl 5 stalled. Python emerged as a viable alternative to Perl 6, drawing attention away from it. However, Perl 5 is still being actively updated, which may spark attention back to it.

If you work with Perl and have more insights into why its popularity has spiked, both we and Jansen are curious.

Other movements on the leaderboard

Most of the buzz around the TIOBE Index this month focused on Perl. However, there are other interesting movements in the top ten. C (in third place) fell slightly from 9.03% in August to 8.65% in September. Java (fourth place) also fell slightly from 8.59% to 8.35%.

Like Perl, the embedded-systems-focused programming language Ada has risen significantly year-over-year, although it has dropped to 14th place after reaching the top 10 in July.

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