<SEC-DOCUMENT>0001517413-25-000355.txt : 20251218
<SEC-HEADER>0001517413-25-000355.hdr.sgml : 20251218
<ACCEPTANCE-DATETIME>20251218172508
ACCESSION NUMBER:		0001517413-25-000355
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20251216
FILED AS OF DATE:		20251218
DATE AS OF CHANGE:		20251218

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Lovett Scott R.
		CENTRAL INDEX KEY:			0002024441
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38897
		FILM NUMBER:		251584091

	MAIL ADDRESS:	
		STREET 1:		C/O FASTLY, INC.
		STREET 2:		475 BRANNAN STREET, SUITE 300
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94107

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Fastly, Inc.
		CENTRAL INDEX KEY:			0001517413
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-PREPACKAGED SOFTWARE [7372]
		ORGANIZATION NAME:           	06 Technology
		EIN:				275411834
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		475 BRANNAN
		STREET 2:		SUITE 300
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94107
		BUSINESS PHONE:		415-525-3481

	MAIL ADDRESS:	
		STREET 1:		475 BRANNAN
		STREET 2:		SUITE 300
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94107

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Skycache, Inc.(DE)
		DATE OF NAME CHANGE:	20110405
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wk-form4_1766096700.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-12-16</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001517413</issuerCik>
        <issuerName>Fastly, Inc.</issuerName>
        <issuerTradingSymbol>FSLY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002024441</rptOwnerCik>
            <rptOwnerName>Lovett Scott R.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O FASTLY, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>475 BRANNAN STREET, SUITE 300</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94107</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President, Go to Market</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>1</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-12-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>34517</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.15</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1044255</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-12-17</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F3"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>42118</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.10</value>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1002137</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Shares sold to satisfy tax obligations in connection with the vesting of previously granted Restricted Stock Units.</footnote>
        <footnote id="F2">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $10.15 to $10.20. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2) and (4) to this Form 4.</footnote>
        <footnote id="F3">The sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on February 28, 2025.</footnote>
        <footnote id="F4">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $9.99 to $10.22, inclusive.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Tara Seracka, Attorney-in-Fact</signatureName>
        <signatureDate>2025-12-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
