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  <xs:element id="mgni_DebtRefinanceCostMember" abstract="true" name="DebtRefinanceCostMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_ExistingLendersMember" abstract="true" name="ExistingLendersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_NewLendersMember" abstract="true" name="NewLendersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_LineOfCreditFacilityCovenantComplianceDebtUtilizationTriggeringLeverageRatioCompliancePercentage" abstract="false" name="LineOfCreditFacilityCovenantComplianceDebtUtilizationTriggeringLeverageRatioCompliancePercentage" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="mgni_LineOfCreditFacilityCovenantComplianceLeverageRatioMaximum" abstract="false" name="LineOfCreditFacilityCovenantComplianceLeverageRatioMaximum" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="mgni_DebtInstrumentPeriodicPaymentPercentageOfPrincipal" abstract="false" name="DebtInstrumentPeriodicPaymentPercentageOfPrincipal" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="mgni_DebtInstrumentAnnualPrincipalPaymentPercentage" abstract="false" name="DebtInstrumentAnnualPrincipalPaymentPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="mgni_DebtInstrumentNoncashOrPartNoncashFinancingActivity" abstract="false" name="DebtInstrumentNoncashOrPartNoncashFinancingActivity" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtDiscountsAbstract" abstract="true" name="AmortizationOfDebtDiscountsAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="mgni_AmortizationOfDebtDiscountPremiumRemainderOfFiscalYear" abstract="false" name="AmortizationOfDebtDiscountPremiumRemainderOfFiscalYear" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtDiscountPremiumYearOne" abstract="false" name="AmortizationOfDebtDiscountPremiumYearOne" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtDiscountPremiumYearTwo" abstract="false" name="AmortizationOfDebtDiscountPremiumYearTwo" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtDiscountPremiumYearThree" abstract="false" name="AmortizationOfDebtDiscountPremiumYearThree" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtDiscountPremiumYearFour" abstract="false" name="AmortizationOfDebtDiscountPremiumYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtDiscountPremiumAfterYearFour" abstract="false" name="AmortizationOfDebtDiscountPremiumAfterYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtIssuanceCostsYearTwo" abstract="false" name="AmortizationOfDebtIssuanceCostsYearTwo" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtIssuanceCostsYearThree" abstract="false" name="AmortizationOfDebtIssuanceCostsYearThree" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtIssuanceCostsYearFour" abstract="false" name="AmortizationOfDebtIssuanceCostsYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtIssuanceCostsAfterYearFour" abstract="false" name="AmortizationOfDebtIssuanceCostsAfterYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodGross" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodGross" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="mgni_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsUnvestedAndVestedButDeferredNumber" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsUnvestedAndVestedButDeferredNumber" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="mgni_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedAndVestedButDeferredWeightedAverageGrantDateFairValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedAndVestedButDeferredWeightedAverageGrantDateFairValue" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="mgni_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodIncludingGrantsAboveTargetWeightedAverageGrantDateFairValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodIncludingGrantsAboveTargetWeightedAverageGrantDateFairValue" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="mgni_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodAboveTarget" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodAboveTarget" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="mgni_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsSelectedPeerCompaniesWeightedAverageVolatilityRate" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsSelectedPeerCompaniesWeightedAverageVolatilityRate" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="mgni_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsCorrelationCoefficients" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsCorrelationCoefficients" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="mgni_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsSelectedPeerCompaniesCorrelationCoefficients" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsSelectedPeerCompaniesCorrelationCoefficients" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="mgni_A2014EmployeeStockPurchasePlanMember" abstract="true" name="A2014EmployeeStockPurchasePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_DavidDayMember" abstract="true" name="DavidDayMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_AdamSorocaMember" abstract="true" name="AdamSorocaMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_PaulCaineMember" abstract="true" name="PaulCaineMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_KatieEvansMember" abstract="true" name="KatieEvansMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_SeanBuckleyMember" abstract="true" name="SeanBuckleyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_DavidBuonaseraMember" abstract="true" name="DavidBuonaseraMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_MichaelBarrettMember" abstract="true" name="MichaelBarrettMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
