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<!-- DFIN ActiveDisclosure(SM) XBRL Schema Document - http://www.dfinsolutions.com/ -->
<!-- Creation Date      : 2021-08-12T02:31:38.7960786+00:00 -->
<!-- Version            : 5.0.1.648 -->
<!-- Package ID         : 18e302c92ff545339df7c6918efcbc4d -->
<!-- Copyright (c) 2021 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
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  <xsd:element id="dsp_NumberOfAdvertisingAgency" name="NumberOfAdvertisingAgency" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="dsp_TaxReceivableAgreementRequiredToMakePaymentsToShareholdersRealizedPercentageOfTaxBenefitsInEventThatExchangeOfUnitsToShares" name="TaxReceivableAgreementRequiredToMakePaymentsToShareholdersRealizedPercentageOfTaxBenefitsInEventThatExchangeOfUnitsToShares" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="dsp_TaxReceivableAgreementExpectedRemainingTaxBenefitPercentage" name="TaxReceivableAgreementExpectedRemainingTaxBenefitPercentage" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="dsp_TaxReceivableAgreementInterestPaymentsAccruedBasisSpreadRate" name="TaxReceivableAgreementInterestPaymentsAccruedBasisSpreadRate" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="dsp_CapitalizedSoftwareDevelopmentCostsMember" name="CapitalizedSoftwareDevelopmentCostsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="dsp_FurnitureFixturesAndOfficeEquipmentMember" name="FurnitureFixturesAndOfficeEquipmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="dsp_PlatformOperationsMember" name="PlatformOperationsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="dsp_TechnologyAndDevelopmentMember" name="TechnologyAndDevelopmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="dsp_AccruedTrafficAcquisitionCosts" name="AccruedTrafficAcquisitionCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="dsp_PaycheckProtectionProgramLoanMember" name="PaycheckProtectionProgramLoanMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="dsp_AccruedInterestForgivenessMember" name="AccruedInterestForgivenessMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="dsp_LoanAgreementMember" name="LoanAgreementMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="dsp_PNCBankMember" name="PNCBankMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="dsp_TwoThousandAndTwentyOneLongTermIncentivePlanMember" name="TwoThousandAndTwentyOneLongTermIncentivePlanMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="dsp_NonqualifiedStockOptionsMember" name="NonqualifiedStockOptionsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="dsp_PercentageOfExclusiveOfNonControllingInterestDueToIncomeTaxExpenseBenefitNotRecognizeOnShareOfPreTaxBookIncomeLoss" name="PercentageOfExclusiveOfNonControllingInterestDueToIncomeTaxExpenseBenefitNotRecognizeOnShareOfPreTaxBookIncomeLoss" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="dsp_TaxReceivableAgreementLiability" name="TaxReceivableAgreementLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="dsp_AntidilutiveSecuritiesExcludedFromEarningsLossPerShareAbstract" name="AntidilutiveSecuritiesExcludedFromEarningsLossPerShareAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="dsp_ExchangeUnitsForSharesOfCommonStock" name="ExchangeUnitsForSharesOfCommonStock" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="dsp_NumberOfUnitsOwned" name="NumberOfUnitsOwned" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="dsp_ViantTechnologyIncMember" name="ViantTechnologyIncMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="dsp_EconomicInterestsOwnershipPercentage" name="EconomicInterestsOwnershipPercentage" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="dsp_OwnershipInterestPercentage" name="OwnershipInterestPercentage" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="dsp_LeaseExpirationYear" name="LeaseExpirationYear" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="dsp_CommitmentsAndContingenciesLineItems" name="CommitmentsAndContingenciesLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="dsp_CommitmentsAndContingenciesTable" name="CommitmentsAndContingenciesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="dsp_LesseeOperatingLeaseLiabilityPaymentsDueYearFourAndThereafter" name="LesseeOperatingLeaseLiabilityPaymentsDueYearFourAndThereafter" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="dsp_RestrictedStockSharesVestedNetOfShares" name="RestrictedStockSharesVestedNetOfShares" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="dsp_SharesRepurchasedAverageFairValuePrice" name="SharesRepurchasedAverageFairValuePrice" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
</xsd:schema>
