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            <identifier scheme="http://www.sec.gov/CIK">0001847367</identifier>
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        <period>
            <startDate>2026-03-17</startDate>
            <endDate>2026-03-17</endDate>
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        <measure>iso4217:USD</measure>
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        <measure>shares</measure>
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    <ffd:SubmissnTp contextRef="rc" id="ixv-454">S-3ASR</ffd:SubmissnTp>
    <ffd:FeeExhibitTp contextRef="rc" id="ixv-455">EX-FILING FEES</ffd:FeeExhibitTp>
    <dei:EntityCentralIndexKey contextRef="rc" id="ixv-456">0001847367</dei:EntityCentralIndexKey>
    <dei:EntityRegistrantName contextRef="rc" id="ixv-457">ALUMIS INC.</dei:EntityRegistrantName>
    <ffd:OfferingTableNa contextRef="rc" id="hiddenrcOfferingTableNa" xsi:nil="true"/>
    <ffd:OffsetTableNa contextRef="rc" id="hiddenrcOffsetTableNa" xsi:nil="true"/>
    <ffd:CombinedProspectusTableNa contextRef="rc" id="hiddenrcCombinedProspectusTableNa">N/A</ffd:CombinedProspectusTableNa>
    <ffd:OffsetClmdInd contextRef="ofst_1" id="ixv-461">true</ffd:OffsetClmdInd>
    <ffd:OffsetClmdInd contextRef="ofst_2" id="ixv-462">false</ffd:OffsetClmdInd>
    <ffd:FormTp contextRef="rc" id="ixv-541">S-3</ffd:FormTp>
    <dei:EntityRegistrantName contextRef="rc" id="ixv-542">ALUMIS INC.</dei:EntityRegistrantName>
    <ffd:PrevslyPdFlg contextRef="offrl_1" id="ixv-543">false</ffd:PrevslyPdFlg>
    <ffd:OfferingSctyTp contextRef="offrl_1" id="ixv-544">Equity</ffd:OfferingSctyTp>
    <ffd:OfferingSctyTitl contextRef="offrl_1" id="ixv-545">Common Stock, $0.0001 par value per share</ffd:OfferingSctyTitl>
    <ffd:Rule457rFlg contextRef="offrl_1" id="ixv-546">true</ffd:Rule457rFlg>
    <ffd:FeeRate
      contextRef="offrl_1"
      decimals="7"
      id="ixv-547"
      unitRef="pure">0.0001381</ffd:FeeRate>
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    <ffd:OfferingSctyTp contextRef="offrl_2" id="ixv-549">Equity</ffd:OfferingSctyTp>
    <ffd:OfferingSctyTitl contextRef="offrl_2" id="ixv-550">Preferred Stock, $0.0001 par value per share</ffd:OfferingSctyTitl>
    <ffd:Rule457rFlg contextRef="offrl_2" id="ixv-551">true</ffd:Rule457rFlg>
    <ffd:FeeRate
      contextRef="offrl_2"
      decimals="7"
      id="ixv-552"
      unitRef="pure">0.0001381</ffd:FeeRate>
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    <ffd:OfferingSctyTitl contextRef="offrl_3" id="ixv-555">Debt Securities</ffd:OfferingSctyTitl>
    <ffd:Rule457rFlg contextRef="offrl_3" id="ixv-556">true</ffd:Rule457rFlg>
    <ffd:FeeRate
      contextRef="offrl_3"
      decimals="7"
      id="ixv-557"
      unitRef="pure">0.0001381</ffd:FeeRate>
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    <ffd:OfferingSctyTp contextRef="offrl_4" id="ixv-559">Other</ffd:OfferingSctyTp>
    <ffd:OfferingSctyTitl contextRef="offrl_4" id="ixv-560">Warrants</ffd:OfferingSctyTitl>
    <ffd:Rule457rFlg contextRef="offrl_4" id="ixv-561">true</ffd:Rule457rFlg>
    <ffd:FeeRate
      contextRef="offrl_4"
      decimals="7"
      id="ixv-562"
      unitRef="pure">0.0001381</ffd:FeeRate>
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    <ffd:OfferingSctyTp contextRef="offrl_5" id="ixv-564">Equity</ffd:OfferingSctyTp>
    <ffd:OfferingSctyTitl contextRef="offrl_5" id="ixv-565">Common Stock, $0.0001 par value per share</ffd:OfferingSctyTitl>
    <ffd:Rule457oFlg contextRef="offrl_5" id="ixv-566">true</ffd:Rule457oFlg>
    <ffd:MaxAggtOfferingPric
      contextRef="offrl_5"
      decimals="2"
      id="ixv-567"
      unitRef="USD">300000000.00</ffd:MaxAggtOfferingPric>
    <ffd:FeeRate
      contextRef="offrl_5"
      decimals="7"
      id="ixv-568"
      unitRef="pure">0.0001381</ffd:FeeRate>
    <ffd:FeeAmt
      contextRef="offrl_5"
      decimals="2"
      id="ixv-569"
      unitRef="USD">41430.00</ffd:FeeAmt>
    <ffd:TtlOfferingAmt contextRef="rc" decimals="2" id="ixv-570" unitRef="USD">300000000.00</ffd:TtlOfferingAmt>
    <ffd:TtlFeeAmt contextRef="rc" decimals="2" id="ixv-571" unitRef="USD">41430.00</ffd:TtlFeeAmt>
    <ffd:TtlPrevslyPdAmt contextRef="rc" decimals="2" id="ixv-572" unitRef="USD">0.00</ffd:TtlPrevslyPdAmt>
    <ffd:TtlOffsetAmt contextRef="rc" decimals="2" id="ixv-573" unitRef="USD">8412.00</ffd:TtlOffsetAmt>
    <ffd:NetFeeAmt contextRef="rc" decimals="2" id="ixv-574" unitRef="USD">33018.00</ffd:NetFeeAmt>
    <ffd:OfferingNote contextRef="offrl_1" id="ixv-575">There are being registered hereunder such indeterminate number of shares of common stock, such indeterminate number of shares of preferred stock, such indeterminate principal amount of debt securities and such indeterminate number of warrants to purchase common stock, preferred stock or debt securities as may be sold from time to time by the Registrant. The securities registered also include such indeterminate number of shares of common stock, preferred stock and amount of debt securities as may be issued upon conversion of or exchange for debt securities that provide for conversion or exchange, upon exercise of warrants or pursuant to the antidilution provisions of any such securities. In addition, pursuant to Rule 416 under the Securities Act of 1933, as amended, or the Securities Act, the shares being registered hereunder include such indeterminate number of shares of common stock and preferred stock as may be issuable with respect to the shares being registered hereunder as a result of stock splits, stock dividends or similar transactions. The proposed maximum per security and aggregate offering prices per class of securities will be determined from time to time by the Registrant in connection with the issuance by the Registrant of the securities registered hereunder and is not specified as to each class of security. Separate consideration may or may not be received for securities that are issuable on exercise, conversion or exchange of other securities. The Registrant is relying on Rules 456(b) and 457(r) under the Securities Act to defer payment of the entire registration fee. In connection with the securities offered hereby, the Registrant will pay "pay-as-you-go registration fees" in accordance with Rule 456(b) under the Securities Act. The Registrant will calculate the registration fee applicable to an offer of securities pursuant to this registration statement based on the fee rate in effect on the date of such fee payment.</ffd:OfferingNote>
    <ffd:OfferingNote contextRef="offrl_2" id="ixv-576">There are being registered hereunder such indeterminate number of shares of common stock, such indeterminate number of shares of preferred stock, such indeterminate principal amount of debt securities and such indeterminate number of warrants to purchase common stock, preferred stock or debt securities as may be sold from time to time by the Registrant. The securities registered also include such indeterminate number of shares of common stock, preferred stock and amount of debt securities as may be issued upon conversion of or exchange for debt securities that provide for conversion or exchange, upon exercise of warrants or pursuant to the antidilution provisions of any such securities. In addition, pursuant to Rule 416 under the Securities Act of 1933, as amended, or the Securities Act, the shares being registered hereunder include such indeterminate number of shares of common stock and preferred stock as may be issuable with respect to the shares being registered hereunder as a result of stock splits, stock dividends or similar transactions. The proposed maximum per security and aggregate offering prices per class of securities will be determined from time to time by the Registrant in connection with the issuance by the Registrant of the securities registered hereunder and is not specified as to each class of security. Separate consideration may or may not be received for securities that are issuable on exercise, conversion or exchange of other securities. The Registrant is relying on Rules 456(b) and 457(r) under the Securities Act to defer payment of the entire registration fee. In connection with the securities offered hereby, the Registrant will pay "pay-as-you-go registration fees" in accordance with Rule 456(b) under the Securities Act. The Registrant will calculate the registration fee applicable to an offer of securities pursuant to this registration statement based on the fee rate in effect on the date of such fee payment.</ffd:OfferingNote>
    <ffd:OfferingNote contextRef="offrl_3" id="ixv-577">There are being registered hereunder such indeterminate number of shares of common stock, such indeterminate number of shares of preferred stock, such indeterminate principal amount of debt securities and such indeterminate number of warrants to purchase common stock, preferred stock or debt securities as may be sold from time to time by the Registrant. The securities registered also include such indeterminate number of shares of common stock, preferred stock and amount of debt securities as may be issued upon conversion of or exchange for debt securities that provide for conversion or exchange, upon exercise of warrants or pursuant to the antidilution provisions of any such securities. In addition, pursuant to Rule 416 under the Securities Act of 1933, as amended, or the Securities Act, the shares being registered hereunder include such indeterminate number of shares of common stock and preferred stock as may be issuable with respect to the shares being registered hereunder as a result of stock splits, stock dividends or similar transactions. The proposed maximum per security and aggregate offering prices per class of securities will be determined from time to time by the Registrant in connection with the issuance by the Registrant of the securities registered hereunder and is not specified as to each class of security. Separate consideration may or may not be received for securities that are issuable on exercise, conversion or exchange of other securities. The Registrant is relying on Rules 456(b) and 457(r) under the Securities Act to defer payment of the entire registration fee. In connection with the securities offered hereby, the Registrant will pay "pay-as-you-go registration fees" in accordance with Rule 456(b) under the Securities Act. The Registrant will calculate the registration fee applicable to an offer of securities pursuant to this registration statement based on the fee rate in effect on the date of such fee payment.</ffd:OfferingNote>
    <ffd:OfferingNote contextRef="offrl_4" id="ixv-578">There are being registered hereunder such indeterminate number of shares of common stock, such indeterminate number of shares of preferred stock, such indeterminate principal amount of debt securities and such indeterminate number of warrants to purchase common stock, preferred stock or debt securities as may be sold from time to time by the Registrant. The securities registered also include such indeterminate number of shares of common stock, preferred stock and amount of debt securities as may be issued upon conversion of or exchange for debt securities that provide for conversion or exchange, upon exercise of warrants or pursuant to the antidilution provisions of any such securities. In addition, pursuant to Rule 416 under the Securities Act of 1933, as amended, or the Securities Act, the shares being registered hereunder include such indeterminate number of shares of common stock and preferred stock as may be issuable with respect to the shares being registered hereunder as a result of stock splits, stock dividends or similar transactions. The proposed maximum per security and aggregate offering prices per class of securities will be determined from time to time by the Registrant in connection with the issuance by the Registrant of the securities registered hereunder and is not specified as to each class of security. Separate consideration may or may not be received for securities that are issuable on exercise, conversion or exchange of other securities. The Registrant is relying on Rules 456(b) and 457(r) under the Securities Act to defer payment of the entire registration fee. In connection with the securities offered hereby, the Registrant will pay "pay-as-you-go registration fees" in accordance with Rule 456(b) under the Securities Act. The Registrant will calculate the registration fee applicable to an offer of securities pursuant to this registration statement based on the fee rate in effect on the date of such fee payment.</ffd:OfferingNote>
    <ffd:Rule457pOffsetFlg contextRef="ofst_1" id="ixv-579">true</ffd:Rule457pOffsetFlg>
    <ffd:OffsetPrrFilerNm contextRef="ofst_1" id="ixv-580">Alumis Inc.</ffd:OffsetPrrFilerNm>
    <ffd:OffsetPrrFormTp contextRef="ofst_1" id="ixv-581">S-3</ffd:OffsetPrrFormTp>
    <ffd:OffsetPrrFileNb contextRef="ofst_1" id="ixv-582">333-288510</ffd:OffsetPrrFileNb>
    <ffd:OffsetClmInitlFilgDt contextRef="ofst_1" id="ixv-583">2025-07-03</ffd:OffsetClmInitlFilgDt>
    <ffd:OffsetClmdAmt contextRef="ofst_1" decimals="2" id="ixv-584" unitRef="USD">8412.00</ffd:OffsetClmdAmt>
    <ffd:OffsetPrrSctyTp contextRef="ofst_1" id="ixv-585">Unallocated (Universal) Shelf</ffd:OffsetPrrSctyTp>
    <ffd:OffsetPrrSctyTitl contextRef="ofst_1" id="ixv-586">Unallocated (Universal) Shelf</ffd:OffsetPrrSctyTitl>
    <ffd:OffsetPrrNbOfUnsoldScties
      contextRef="ofst_1"
      decimals="0"
      id="ixv-587"
      unitRef="Shares">54942500</ffd:OffsetPrrNbOfUnsoldScties>
    <ffd:OffsetPrrUnsoldOfferingAmt contextRef="ofst_1" decimals="2" id="ixv-588" unitRef="USD">54942500.00</ffd:OffsetPrrUnsoldOfferingAmt>
    <ffd:Rule457pOffsetFlg contextRef="ofst_2" id="ixv-589">true</ffd:Rule457pOffsetFlg>
    <ffd:OffsetPrrFilerNm contextRef="ofst_2" id="ixv-590">Alumis Inc.</ffd:OffsetPrrFilerNm>
    <ffd:OffsetPrrFormTp contextRef="ofst_2" id="ixv-591">S-3</ffd:OffsetPrrFormTp>
    <ffd:OffsetPrrFileNb contextRef="ofst_2" id="ixv-592">333-288510</ffd:OffsetPrrFileNb>
    <ffd:OffsetSrcFilgDt contextRef="ofst_2" id="ixv-593">2025-07-03</ffd:OffsetSrcFilgDt>
    <ffd:OffsetPrrFeeAmt contextRef="ofst_2" decimals="2" id="ixv-594" unitRef="USD">61240.00</ffd:OffsetPrrFeeAmt>
    <ffd:TermntnCmpltnWdrwl contextRef="ofst_1" id="ixv-595">The Registrant previously registered $400,000,000 of an indeterminate amount of securities to be offered from time to time at prices to be determined at the time of each such offering pursuant to a Registration Statement on Form S-3 (File No. 333-288510) filed with the Securities and Exchange Commission (the "Commission") on July 3, 2025, and declared effective by the Commission on August 19, 2025 (the "Prior Registration Statement"). The Registrant previously paid an aggregate registration fee of $61,240 in connection with the Prior Registration Statement (based on the filing fee rate in effect at the time of the filing of the Prior Registration Statement). As of the date of filing of this Registration Statement, the Registrant sold an aggregate of $345,057,500 of such securities under the Prior Registration Statement, leaving the balance of $54,942,500 (the "Unsold Securities"), representing $8,412 in registration fees, of such Unsold Securities under the Prior Registration Statement. Pursuant to Rule 457(p) under the Securities Act, such unutilized filing fees may be applied to the filing fees payable pursuant to this Registration Statement. All offerings under the Prior Registration Statement have terminated.</ffd:TermntnCmpltnWdrwl>
    <ffd:OffsetNote contextRef="ofst_2" id="ixv-596">The Registrant previously registered $400,000,000 of an indeterminate amount of securities to be offered from time to time at prices to be determined at the time of each such offering pursuant to a Registration Statement on Form S-3 (File No. 333-288510) filed with the Securities and Exchange Commission (the "Commission") on July 3, 2025, and declared effective by the Commission on August 19, 2025 (the "Prior Registration Statement"). The Registrant previously paid an aggregate registration fee of $61,240 in connection with the Prior Registration Statement (based on the filing fee rate in effect at the time of the filing of the Prior Registration Statement). As of the date of filing of this Registration Statement, the Registrant sold an aggregate of $345,057,500 of such securities under the Prior Registration Statement, leaving the balance of $54,942,500 (the "Unsold Securities"), representing $8,412 in registration fees, of such Unsold Securities under the Prior Registration Statement. Pursuant to Rule 457(p) under the Securities Act, such unutilized filing fees may be applied to the filing fees payable pursuant to this Registration Statement. All offerings under the Prior Registration Statement have terminated.</ffd:OffsetNote>
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