Diddy went above and beyond to make sure his guests were safe at his birthday party ... making sure security was on point after a gun issue caused a scene the last time he hosted a shindig.
Law enforcement sources tell TMZ ... the legendary rap mogul had super tight security Friday night for his 53rd birthday bash, with everyone in attendance passing through a metal detector before being allowed inside.
The party went down at Diddy's Los Angeles mansion and we're told one of the streets by his estate was shut down. Our sources say guests were shuttled up to the house, and if they weren't on the list, they were turned away ... no exceptions.
It appears Diddy wasn't taking any chances after what happened this past summer, when he hosted a BET after-party at the same property -- as we first reported, a woman trying to make her way into the after-party was arrested outside Diddy's house after allegedly flashing a gun at other partygoers.
The beefed-up security also follows some recent fatal gun violence involving rappers Takeoff and PnB Rock, who were both shot dead.
Diddy's security seemed to work too ... we're told there were no issues surrounding the party.
As we reported ... Diddy's bash was crawling with celebs, including Travis Scott, Jay-Z, Mary J. Blige, Chris Brown, French Montana, Machine Gun Kelly, Teyana Taylor, Tinashe and Jermaine Dupri and Kehlani.
Diddy had Nobu cater the event and he was lavished with gifts, with several cakes spelling out "Love." A huge mattress was set up in the backyard, where partygoers danced their faces off with the man of the hour.