Revenue - Schedule of total revenue by geographic areas (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2021	Oct. 31, 2020	Oct. 31, 2021	Oct. 31, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 226,893	$ 150,771	$ 607,288	$ 419,381
MongoDB Atlas-related
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	131,123	71,110	336,390	186,354
Other subscription
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	86,748	72,959	247,432	215,049
Services
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	9,022	6,702	23,466	17,978
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	138,036	93,255	368,339	261,836
Europe, Middle East and Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	66,183	44,552	178,490	123,762
Asia Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 22,674	$ 12,964	$ 60,459	$ 33,783