Net Income (Loss) Per Share - Summary of Basic and Diluted Net Income (Loss) Per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net income (loss) attributable to AppLovin	$ 178	$ 14,423	$ (10,521)	$ (89,688)	$ (21,391)	$ 4,664	$ 4,080	$ (106,415)
Less:
Income attributable to convertible preferred stock	0			0			(499)	0
Income attributable to options exercised via promissory notes	(1)			0			(49)	0
Income attributable to unvested early exercised options	0			0			(13)	0
Income attributable to unvested RSA’s	0			0			(7)	0
Net income (loss) attributable to common stock—Basic	$ 177			$ (89,688)			$ 3,512	$ (106,415)
Denominator:
Weighted-average shares used in computing net income (loss) per share—Basic (in shares)	368,427,532			214,638,272			309,353,304	212,998,263
Net income (loss) per share attributable to common stock—Basic (in dollars per share)	$ 0.00			$ (0.42)			$ 0.01	$ (0.50)
Numerator:
Net income (loss) attributable to AppLovin	$ 178	$ 14,423	$ (10,521)	$ (89,688)	$ (21,391)	$ 4,664	$ 4,080	$ (106,415)
Less:
Income attributable to convertible preferred stock	0			0			(475)	0
Income attributable to options exercised via promissory notes	(1)			0			(47)	0
Income attributable to unvested early exercised options	0			0			(12)	0
Income attributable to unvested RSA’s	0			0			(7)	0
Net income (loss) attributable to common stock—Diluted	$ 177			$ (89,688)			$ 3,539	$ (106,415)
Denominator:
Weighted-average shares used in computing net income (loss) per share—Basic (in shares)	368,427,532			214,638,272			309,353,304	212,998,263
Weighted-average dilutive stock options (in shares)	15,897,253			0			18,073,488
Weighted-average shares used in computing net income (loss) per share—Diluted (in shares)	384,324,785			214,638,272			327,426,792	212,998,263
Net income (loss) per share attributable to common stock—Diluted (in dollars per share)	$ 0.00			$ (0.42)			$ 0.01	$ (0.50)