Hey! Great article!

Psalm is the youngest of the three, but I think work started for all of them around the same time (mid 2015).

June 2015: I break something in Vimeo’s codebase and start writing a first pass at a PHP5-compatible static analysis tool

July 2015: Rasmus tweets about Phan, a PHP7-based tool he’s working on

December 2015: first public release of Phan

Jan 2016: I migrate my work to a separate repo

April 2016: I discover Phan, but it’s PHP7-only and requires php-ast and it’ll also be another year before Vimeo migrates everything to PHP7. Besides, by then Psalm was better in a few key areas.

July 2016: first public release of PHPStan

November 2016: first public release of Psalm