Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2020
Income Statement [Abstract]
Revenue	$ 204,799	$ 93,056	$ 46,474
Cost of revenue	81,677	39,332	18,331
Gross profit	123,122	53,724	28,143
Operating expenses:
Research and development	136,274	62,444	36,683
Sales and marketing	160,576	77,740	51,322
General and administrative	93,504	29,059	15,122
Total operating expenses	390,354	169,243	103,127
Loss from operations	(267,232)	(115,519)	(74,984)
Interest income	202	231	886
Interest expense	(787)	(1,401)	(2,015)
Other income (expense), net	(2,280)	(424)	(217)
Loss before provision for income taxes	(270,097)	(117,113)	(76,330)
Provision for income taxes	1,004	460	237
Net loss	$ (271,101)	$ (117,573)	$ (76,567)
Net loss per share attributable to Class A and Class B common stockholders, basic (in USD per share)	$ (1.56)	$ (3.31)	$ (2.34)
Net loss per share attributable to Class A and Class B common stockholders, diluted (in USD per share)	$ (1.56)	$ (3.31)	$ (2.34)
Weighted-average shares used in computing net loss per share attributable to Class A and Class B common stockholders, basic (in shares)	174,051,203	35,482,444	32,712,350
Weighted-average shares used in computing net loss per share attributable to Class A and Class B common stockholders, diluted (in shares)	174,051,203	35,482,444	32,712,350