v3.26.1
Cover Page Cover Page
 12 Months Ended
Jun. 30, 2026
Jan. 31, 2027
Cover Page [Abstract]    
Document Type 8-K  
Document Period End Date Jun. 30, 2026  
Entity Registrant Name MONGODB, INC.  
Entity Incorporation, State or Country Code DE  
Entity File Number 001-38240  
Entity Tax Identification Number 26-1463205  
Entity Address, Address Line One 1633 Broadway,  
Entity Address, Address Line Two 38th Floor  
Entity Address, City or Town New York,  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 10019  
City Area Code 646  
Local Phone Number 727-4092  
Written Communications false  
Soliciting Material false  
Pre-commencement Tender Offer false  
Pre-commencement Issuer Tender Offer false  
Title of 12(b) Security Common Stock, par value $0.001 per share  
Trading Symbol MDB  
Security Exchange Name NASDAQ  
Entity Emerging Growth Company false  
Entity Central Index Key 0001441816  
Amendment Flag false  
Current Fiscal Year End Date   --01-31