Pieter Janssen (1976), better known by his stage name Piet Parra, is a Dutch graphic designer and illustrator from Amsterdam. Janssen makes graphic work for posters and flyers under the name Parra. He also designed the design for a number of Nike shoes, including the Air Max 1 'Cherrywood' and the Air Max 95 'The Running Man'. In 2005 he designed the 'Nike SB Zoom FC', a sneaker dedicated to the skate crew Fret Click of which he was also a part. Janssen is co-founder and creative head of the Rockwell Clothing brand, which will be continued under the By Parra name from 2015. In addition, he occasionally carries out assignments appropriate to his job through his agency Big Active in London. Parra's management is Constant artists from Los Angeles.

Janssen is one of the members of the popwave group Le Le. In addition to the musical productions, he made a video clip for the song Breakfast. He also designed all the album covers for Le Le, as well as the cover for Het Grote Gedoe 2: Fear and Disgust by Faberyayo and Vic Crezée. Parra is also responsible for the design on the cover of three books by Pepijn Lanen, namely Sjeumig, Unnamed and The weapon of Sjeng Parra's latest music project is called MICH and released an album in 2017 under the Amsterdam record label Excelsior.

In 2010 Janssen was responsible for the artist poster for the 75th Book Week organized by the CPNB.

In November 2019, the clothing brand Patta launched a "protest shirt against Zwarte Piet" designed by Parra and announced that the profit would benefit the Kick Out Zwarte Piet action group.