Cover - shares	3 Months Ended
	Mar. 31, 2025	Apr. 30, 2025
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2025
Document Transition Report	false
Entity File Number	001-41983
Entity Registrant Name	Reddit, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	45-2546501
Entity Address, Address Line One	303 2nd Street
Entity Address, Address Line Two	South Tower
Entity Address, Address Line Three	5th Floor
Entity Address, City or Town	San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94107
City Area Code	415
Local Phone Number	494-8016
Title of 12(b) Security	Class A common stock, par value $0.0001 per share
Trading Symbol	RDDT
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
CIK	0001713445
Amendment Flag	false
Class A common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		129,546,488
Class B common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		54,974,124
Class C common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		0