v3.25.3

Cover - USD ($) $ in Millions	12 Months Ended
Cover - USD ($) $ in Millions	Dec. 31, 2024	Feb. 28, 2025	Jun. 30, 2024
Document Information [Line Items]
Document Type	10-K/A
Document Annual Report	true
Document Period End Date	Dec. 31, 2024
Document Fiscal Year Focus	2024
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-40015
Entity Registrant Name	Viant Technology Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	85-3447553
Entity Address, Address Line One	2722 Michelson Drive
Entity Address, Address Line Two	Suite 100
Entity Address, City or Town	Irvine
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92612
City Area Code	949
Local Phone Number	861-8888
Title of 12(b) Security	Class A common stock, par value $0.001 per share
Trading Symbol	DSP
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 155.5
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s definitive Proxy Statement for its 2025 Annual Meeting of Stockholders, which the registrant intends to file pursuant to Regulation 14A with the Securities and Exchange Commission no later than 120 days after the registrant’s fiscal year ended December 31, 2024, are incorporated by reference into Part III of this Annual Report on Form 10-K.
Entity Central Index Key	0001828791
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Small Business	true
Common Class A
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		16,353,549
Common Class B
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		46,720,212

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Viant Technology Inc. 10-K/A