What is what number is messi?

As an AI language model, I cannot determine with certainty what number Messi currently wears, as it can change depending on the team and competition rules. However, here are some common numbers Messi has worn throughout his career:

• Barcelona: He has worn number 10 for most of his career at Barcelona, the same number famously worn by Maradona and also a number commonly associated with creative and attacking midfielders. However, he has also briefly worn number 19 and number 30.
• Argentina: Messi has often worn number 10 for the national team, but has also worn number 18 and number 19 in some matches.
• Other teams: Messi has not played for many other teams, but when he briefly played for Newell's Old Boys as a child, he wore number 10, the same number as at Barcelona.