The important thing to know about writer-director Sean Baker’s film isn’t that it was shot entirely on an iPhone, or that it’s the buzziest tale of trans-sex-worker revenge you’re likely to encounter on a screen this year. Those things are true, but what’s important about Tangerine is that it’s so cathartically hilarious. Cathartic not just because the characters answer their cruel circumstances with such rambunctious wit, but because the movie itself dares to be funny in the first place. Fresh from a brief stint in jail, Sin-Dee Rella (Kitana Kiki Rodriguez) is furious to learn that her pimp boyfriend (James Ransone) had the nerve to cheat with a biological female. Now with best friend Alexandra (Mya Taylor) in tow, Sin-Dee sets out to track the bastard down. Alexandra has an agenda of her own, in a lower key, and Baker, co-scripting with Chris Bergoch, makes some nice quiet space for that too. A compassionate farce, the tale takes place on Christmas Eve, with the warm fuzzies of the season glinting improbably within the sallow glow of L.A. streets, as key scenes play out in a donut shop, a car wash, and a laundromat. Aside from the gloriously vulgar music of the characters’ rapid-fire chatter, there’s a little dubstep here, a little Beethoven there, and never a dull moment to be found. Executive produced by Jay and Mark Duplass, Tangerine should help dispel the critique of certain Duplassian white-dude-ist tendencies, but there’s a broader cultural value, too. It’s at once a triumphant return to indie-film first principles — rawness, resourcefulness, sheer delight to be doing it at all — and a hot, strong breath of fresh air.