Cover - shares	3 Months Ended
	Mar. 31, 2024	Oct. 11, 2024
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	001-41261
Entity Registrant Name	DIRECT DIGITAL HOLDINGS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	87-2306185
Entity Address, Address Line One	1177 West Loop South
Entity Address, Address Line Two	Suite 1310
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77027
City Area Code	832
Local Phone Number	402-1051
Title of 12(b) Security	Class A Common Stock, par value $0.001 per share
Trading Symbol	DRCT
Security Exchange Name	NASDAQ
Entity Current Reporting Status	No
Entity Interactive Data Current	No
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Amendment Flag	false
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001880613
Current Fiscal Year End Date	--12-31
Class A
Entity Common Stock, Shares Outstanding		3,795,199
Class B Common Stock
Entity Common Stock, Shares Outstanding		10,868,000