EX-10.5





 Exhibit 10.5 

Execution Version 

November 3, 2021 
 Juniper II Corp. 

3790 El Camino Real #818 
 Palo Alto, California 94306 

Morgan Stanley 
 1585 Broadway, 36th Floor 

New York, NY 10036 
 UBS Securities LLC 

1285 Avenue of the Americas 
 New York, NY 10019 

Re: Initial Public Offering 
 Ladies and Gentlemen: 

This letter (this “Letter Agreement”) is being delivered to you in accordance with the Underwriting Agreement (the
“Underwriting Agreement”) to be entered into by and between Juniper II Corp., a Delaware corporation (the “Company”), Morgan Stanley and UBS Securities LLC (the “Underwriters”),
relating to an underwritten initial public offering (the “Public Offering”), of 26,000,000 of the Company’s units (including up to 3,900,000 units that may be purchased to cover over-allotments, if any) (the
“Units”), each comprised of one share of the Company’s Class A common stock, par value $0.0001 per share (the “Common Stock”), and one-half of one
warrant. Each whole Warrant (each, a “Warrant”) entitles the holder thereof to purchase one share of Common Stock at a price of $11.50 per share, subject to adjustment. The Units will be sold in the Public Offering pursuant
to a registration statement on Form S-1 and a prospectus (the “Prospectus”) included therein, filed by the Company with the Securities and Exchange Commission (the
“Commission”) and the Company has applied to have the Units listed on the New York Stock Exchange. Certain capitalized terms used herein are defined in paragraph 12 hereof. 

In order to induce the Company and the Underwriters to enter into the Underwriting Agreement and to proceed with the Public Offering and for
other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, Juniper II Management, LLC, a Delaware limited liability company (the “Sponsor”), and the undersigned individuals, each of
whom is a member of the Company’s board of directors, a nominee for membership on the board of directors and/or an executive officer of the Company’s (each, an “Insider” and collectively, the
“Insiders”), hereby agrees with the Company as follows: 
 1. It is acknowledged and agreed that the Company shall
not enter into a definitive agreement regarding a proposed Business Combination without the prior consent of the Sponsor. The Sponsor and each Insider agrees that if the Company seeks stockholder approval of a proposed Business Combination, then in
connection with such proposed Business Combination, it, he or she shall (i) vote any shares of Capital Stock owned by it, him or her in favor of any proposed Business Combination and (ii) not redeem any shares of Common Stock owned by it,
him or her in connection with such stockholder approval. If the Company seeks to consummate a proposed Business Combination by engaging in a tender offer, the Sponsor and each Insider agrees that it, he or she will not sell or tender any shares of
Common Stock owned by it, him or her in connection therewith. 












 2. In the event that the Company fails to consummate a Business Combination within eighteen
(18) months, the Company may extend the time period by which it must consummate a Business Combination by an additional six (6) months for a total of 24 months, provided the Sponsor its affiliates or its designees deposits into the Trust
Account (as defined below) an amount equal to 1% of the gross proceeds of the Public Offering, representing $0.10 for each Unit sold in the Public Offering on or prior to the 18-month anniversary of the
closing of the Public Offering. Such payment would be in the form of a non-interest-bearing loan. Pursuant to this Letter Agreement, the Sponsor has agreed to waive its right to be repaid for such loan in the
event that the Company fails to consummate a Business Combination. Notwithstanding anything to the contrary herein, the Sponsor, its affiliates and its designees shall not be obligated to fund the Trust Account to extend the time for the Company to
consummate a Business Combination. 
 The Sponsor and each Insider hereby agrees that in the event that the Company fails to consummate a
Business Combination within 18 months (or up to 24 months if the Company extends the period of time to consummate a Business Combination, in accordance with the Company’s amended and restated certificate of incorporation (as it may be amended
from time to time, the “Charter”)) from the closing of the Public Offering, or such later period approved by the Company’s stockholders in accordance with the Company’s Charter, the Sponsor and each Insider shall take all
reasonable steps to cause the Company to (i) cease all operations except for the purpose of winding up, (ii) as promptly as reasonably possible but not more than 10 business days thereafter, subject to lawfully available funds therefor,
redeem 100% of the Common Stock sold as part of the Units in the Public Offering (the “Offering Shares”), at a per-share price, payable in cash, equal to the aggregate amount then on
deposit in the Trust Account, including interest earned on the funds held in the Trust Account and not previously released to the Company to pay franchise and income taxes (less up to $100,000 of such net interest to pay dissolution expenses),
divided by the number of then outstanding Offering Shares, which redemption will completely extinguish all Public Stockholders’ rights as stockholders (including the right to receive further liquidation distributions, if any), subject to
applicable law, and (iii) as promptly as reasonably possible following such redemption, subject to the approval of the Company’s remaining stockholders and the Company’s board of directors, dissolve and liquidate, subject in each case
to the Company’s obligations under Delaware law to provide for claims of creditors and other requirements of applicable law. The Sponsor and each Insider agrees to not propose any amendment to the Company’s Charter that would affect the
substance or timing of the Company’s obligation to redeem 100% of the Offering Shares if the Company does not complete a Business Combination within the time period set forth in the Company’s Charter with respect to any other provisions
relating to the rights of holders of our Common Stock, unless the Company provides its public stockholders with the opportunity to redeem their Offering Shares upon approval of any such amendment at a
per-share price, payable in cash, equal to the aggregate amount then on deposit in the Trust Account, including interest earned on the funds held in the Trust Account and not previously released to the Company
to pay its franchise and income taxes, divided by the number of then outstanding Offering Shares. 

  
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 The Sponsor and each Insider acknowledges that it or he or she has no right, title, interest
or claim of any kind in or to any monies held in the Trust Account or any other asset of the Company as a result of any liquidation of the Company with respect to the Founder Shares held by it. The Sponsor and each Insider hereby further waives,
with respect to any shares of Common Stock held by it or him, if any, any redemption rights it or he or she may have in connection with the consummation of a Business Combination, including, without limitation, any such rights available in the
context of a stockholder vote to approve such Business Combination or in the context of a tender offer made by the Company to purchase shares of Common Stock (although the Sponsor, the Insiders and their respective affiliates shall be entitled to
redemption and liquidation rights with respect to any shares of Common Stock it or they hold if the Company fails to consummate a Business Combination within the time period set forth in the Company’s Charter 

3. The undersigned acknowledges and agrees that prior to entering into a definitive agreement for a Business Combination with a target business
that is affiliated with the undersigned or any other Insiders of the Company or their affiliates, such transaction must be approved by a majority of the Company’s disinterested independent directors and the Company must obtain an opinion from
an independent investment banking firm, which is a member of the Financial Industry Regulatory Authority, or an independent accounting firm that such Business Combination is fair to the Company’s unaffiliated stockholders from a financial point
of view. 
 4. During the period commencing on the effective date of the Underwriting Agreement and ending 180 days after such date, the
Sponsor and each Insider shall not, without the prior written consent of the Underwriters, Transfer any Units, shares of Common Stock, Founder Shares, Warrants or any securities convertible into, or exercisable, or exchangeable for, shares of Common
Stock owned by it or him. Each of the Insiders and the Sponsor acknowledges and agrees that, prior to the effective date of any release or waiver, of the restrictions set forth in this paragraph 4 or paragraph 8 below, the Company shall announce the
impending release or waiver by press release through a major news service at least two business days before the effective date of the release or waiver. Any release or waiver granted shall only be effective two business days after the publication
date of such press release. The provisions of this paragraph will not apply if the release or waiver is effected solely to permit a transfer not for consideration and the transferee has agreed in writing to be bound by the same terms described in
this Letter Agreement to the extent and for the duration that such terms remain in effect at the time of the transfer. 
 5. In the event of
the liquidation of the Trust Account, the Sponsor (which for purposes of clarification shall not extend to any other shareholders, members or managers of the Sponsor, or any of the other undersigned) agrees to indemnify and hold harmless the Company
against any and all loss, liability, claim, damage and expense whatsoever (including, but not limited to, any and all legal or other expenses reasonably incurred in investigating, preparing or defending against any litigation, whether pending or
threatened, or any claim whatsoever) to which the Company may become subject as a result of any claim by (i) any third party for services rendered or products sold to the Company or (ii) a prospective target business with which the Company has
entered into an acquisition agreement (a “Target”); provided, however, that such indemnification of the Company by the Sponsor shall apply only to the extent necessary to ensure that such claims by a third party
for services rendered (other than the Company’s independent public accountants) or products sold to the Company or a Target do not reduce the amount of funds in the Trust Account to below (i) $10.20 per share of the Offering Shares or
(ii) such lesser amount per share of the Offering Shares held in the Trust Account due to reductions in the value of the trust assets as of the date of the liquidation of the Trust Account, in each case, net of the amount of interest earned on
the property in the Trust Account which may be withdrawn to pay franchise and income taxes, except as to any claims by a third party (including a Target) who executed a waiver of 

  
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any and all rights to seek access to the Trust Account and except as to any claims under the Company’s indemnity of the Underwriters against certain liabilities, including liabilities under
the Securities Act of 1933, as amended (the “Securities Act”). In the event that any such executed waiver is deemed to be unenforceable against such third party, the Sponsor shall not be responsible to the extent of any
liability for such third party claims. The Sponsor shall have the right to defend against any such claim with counsel of its choice reasonably satisfactory to the Company if, within 15 days following written receipt of notice of the claim to the
Sponsor, the Sponsor notifies the Company in writing that it shall undertake such defense. 
 6. To the extent that the Underwriters do not
exercise its over-allotment option to purchase up to an additional 3,900,000 Units within 45 days from the date of the Prospectus (and as further described in the Prospectus), the Sponsor agrees to forfeit, at no cost, a number of Founder Shares in
the aggregate equal to 975,000 multiplied by a fraction, (i) the numerator of which is 3,900,000 minus the number of Units purchased by the Underwriters upon the exercise of their over-allotment option, and (ii) the denominator of which is
3,900,000. The forfeiture will be adjusted to the extent that the over-allotment option is not exercised in full by the Underwriters so that the Initial Stockholders will own an aggregate of 20.0% of the Company’s issued and outstanding shares
of Capital Stock after the Public Offering (not including shares of Common Stock underlying the Warrants or Private Placement Warrants). 

7. (a) In order to minimize potential conflicts of interest that may arise from multiple corporate affiliations, the Insiders hereby agree that
until the earliest of the Company’s initial Business Combination or liquidation, the Insiders shall present to the Company for its consideration, prior to presentation to any other entity, any target business that has a fair market value of at
least 80% of the assets held in the Trust Account (excluding the amount of deferred underwriting discounts held in trust and taxes payable on the interest earned on the trust account), subject to any existing or future fiduciary or contractual
obligations the undersigned might have. 
 (b) The Sponsor and each Insider hereby agrees and acknowledges that: (i) the Underwriters and the
Company would be irreparably injured in the event of a breach by such Sponsor or an Insider of its, his or her obligations under paragraphs 1, 2, 3, 4, 5, 6, 7(a), 7(b), 8(a), 8(b), and 10, as applicable, of this Letter Agreement (ii) monetary
damages may not be an adequate remedy for such breach and (iii) the non-breaching party shall be entitled to injunctive relief, in addition to any other remedy that such party may have in law or in
equity, in the event of such breach. 
 8. (a) The Sponsor and each Insider agrees that it, he or she shall not Transfer any Founder Shares
(or shares of Common Stock issuable upon conversion thereof) until the earlier of (A) one year after the completion of the Company’s initial Business Combination or (B) subsequent to the Business Combination, (x) if the closing
price of the Common Stock equals or exceeds $12.00 per share (as adjusted for stock splits, stock dividends, reorganizations, recapitalizations and the like) for any 20 trading days within any 30-trading day
period commencing at least 150 days after the Company’s initial Business Combination or (y) the date on which the Company completes a liquidation, merger, capital stock exchange, reorganization or other similar transaction that results in
all of the Company’s stockholders having the right to exchange their shares of Common Stock for cash, securities or other property (the “Founder Shares Lock-up Period”). 

  
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 (b) The Sponsor and each Insider agrees that it, he or she shall not Transfer any Private
Placement Warrants (or shares of Common Stock issued or issuable upon the exercise of the Private Placement Warrants), until 30 days after the completion of a Business Combination (the “Private Placement Warrants Lock-up Period”, together with the Founder Shares Lock-up Period, the “Lock-up Periods”). 

(c) Notwithstanding the provisions set forth in paragraphs 8(a) and (b), Transfers of the Founder Shares, Private Placement Warrants and shares
of Common Stock issued or issuable upon the exercise or conversion of the Private Placement Warrants or the Founder Shares and that are held by the Sponsor, any Insider or any of their permitted transferees (that have complied with this paragraph
8(c)), are permitted (a) to the Company’s officers or directors, any affiliates or family members of any of the Company’s officers or directors, any members of the Sponsor or any affiliate of the members of the Sponsor, any affiliates
of the Sponsor, or any employees of such affiliates; (b) in the case of an individual, transfers by gift to a member of the individual’s immediate family, to a trust, the beneficiary of which is a member of the individual’s immediate
family or an affiliate of such person, or to a charitable organization; (c) in the case of an individual, transfers by virtue of laws of descent and distribution upon death of the individual; (d) in the case of an individual, transfers
pursuant to a qualified domestic relations order; (e) transfers by private sales or transfers made in connection with the consummation of a Business Combination at prices no greater than the price at which the securities were originally
purchased; (f) transfers in the event of the Company’s liquidation prior to the completion of an initial Business Combination; (g) transfers by virtue of the laws of the State of Delaware or the Sponsor’s limited liability
company agreement upon dissolution of the Sponsor; (h) to the Company for no value for cancellation in connection with the consummation of an initial Business Combination or pursuant to paragraph 6 herein; and (i) in the event of the
Company’s liquidation, merger, capital stock exchange, reorganization or other similar transaction which results in all of the Company’s stockholders having the right to exchange their shares of Common Stock for cash, securities or other
property subsequent to the completion of the Company’s initial Business Combination; provided, however, that in the case of clauses (a) through (e) these permitted transferees must enter into a written agreement agreeing to be bound by the
restrictions herein. 
 9. Each of the Insiders agrees to be a director or officer of the Company, as applicable, until the earlier of the
consummation by the Company of an initial Business Combination, the liquidation of the Company, or his or her removal, death or incapacity. In the event of the removal or resignation of an Insider as a director or officer (as applicable), each
Insider agrees that he or she will not, prior to the consummation of the Business Combination, without the prior express written consent of the Company, (i) use for the benefit of the undersigned or to the detriment of the Company or
(ii) disclose to any third party (unless required by law or governmental authority), any information regarding a potential target of the Company that is not generally known by persons outside of the Company, the Sponsor, or their respective
affiliates. The Sponsor and each Insider represents and warrants that it, he or she has never been suspended or expelled from membership in any securities or commodities exchange or association or had a securities or commodities license or
registration denied, suspended or revoked. Each Insider’s biographical information furnished to the Company (including any such information included in the Prospectus) is true and accurate in all respects and does not omit any material
information with respect to the Insider’s background and contains all of the information required to be disclosed pursuant to Item 401 of Regulation S-K, promulgated under the Securities Act. Each
Insider’s questionnaire furnished to the Company and the Underwriters is true and accurate in all 

  
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material respects. Each Insider represents and warrants that: it, he or she is not subject to or a respondent in any legal action for, any injunction, cease-and-desist order or order or stipulation to desist or refrain from any act or practice relating to the offering of securities in any jurisdiction; it or he or she has never been convicted of, or pleaded
guilty to, any crime (i) involving fraud, (ii) relating to any financial transaction or handling of funds of another person, or (iii) pertaining to any dealings in any securities and it or he or she is not currently a defendant in any such
criminal proceeding. 
 10. Except as disclosed in the Prospectus, neither the Sponsor nor any Insider nor any affiliate of the Sponsor or
any Insider, nor any director or officer of the Company, shall receive from the Company any finder’s fee, reimbursement, consulting fee, monies in respect of any repayment of a loan or other compensation prior to, or in connection with any
services rendered in order to effectuate the consummation of the Company’s initial Business Combination (regardless of the type of transaction that it is), other than the following, none of which will be made from the proceeds held in the Trust
Account prior to the completion of the initial Business Combination: repayment of a loan and advances up to an aggregate of $300,000 made to the Company by the Sponsor; payment to an affiliate of the Sponsor for office space, utilities and
secretarial and administrative support for a total of $10,000 per month; interest earned on the funds held in the trust account may be released to the Company to pay its franchise and income tax obligations; reimbursement for any reasonable out-of-pocket expenses related to identifying, investigating and consummating an initial Business Combination, and repayment of loans, if any, and on such terms as to be
determined by the Company from time to time, made by the Sponsor or any of the Company’s officers or directors to finance transaction costs in connection with an intended initial Business Combination, provided, that, if the Company does not
consummate an initial Business Combination, a portion of the working capital held outside the Trust Account may be used by the Company to repay such loaned amounts so long as no proceeds from the Trust Account are used for such repayment. Up to
$1,500,000 of such loans may be convertible into warrants at a price of $1.00 per whole warrant at the option of the lender. Such warrants would be identical to the Private Placement Warrants, including as to exercise price, exercisability and
exercise period. 
 11. The Sponsor and each Insider has full right and power, without violating any agreement to which it is bound
(including, without limitation, any non-competition or non-solicitation agreement with any employer or former employer), to enter into this Letter Agreement and, as
applicable, to serve as a director on the board of directors of the Company and hereby consents to being named in the Prospectus as a director of the Company. 

12. As used herein, (i) “Business Combination” shall mean a merger, capital stock exchange, asset acquisition, stock
purchase, reorganization or similar business combination, involving the Company and one or more businesses; (ii) “Capital Stock” shall mean, collectively, the Common Stock and the Founder Shares; (iii) “Founder
Shares” shall mean the 7,475,000 shares of the Company’s Class B common stock, par value $0.0001 per share, issued and outstanding immediately prior to the consummation of the Public Offering (up to 975,000 shares of which are
subject to complete or partial forfeiture by the Sponsor if the over-allotment option is not exercised by the Underwriters); (iv) “Initial Stockholders” shall mean the Sponsor and any Insider that holds Founder Shares; (v)
“Private Placement Warrants” shall mean the Warrants to purchase 13,400,000 shares of Common Stock of the Company (or 14,960,000 shares of Common Stock if the over-allotment option is exercised in full) that the
Sponsor has agreed to purchase for an aggregate purchase price of $13,400,000 (or $14,960,000 if the over-allotment option is exercised in full), or $1.00 per 

  
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Warrant, in a private placement that shall occur simultaneously with the consummation of the Public Offering; (vi) “Public Stockholders” shall mean the holders of
securities issued in the Public Offering; (vii) “Trust Account” shall mean the trust fund into which a portion of the net proceeds of the Public Offering and certain of the proceeds from the sale of the Private Placement
Warrants shall be deposited; and (viii) “Transfer” shall mean the (a) sale of, offer to sell, contract or agreement to sell, hypothecate, pledge, grant of any option to purchase or otherwise dispose of or agreement to
dispose of, directly or indirectly, or establishment or increase of a put equivalent position or liquidation with respect to or decrease of a call equivalent position within the meaning of Section 16 of the Securities Exchange Act of 1934, as
amended, and the rules and regulations of the Commission promulgated thereunder with respect to, any security, (b) entry into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of
ownership of any security, whether any such transaction is to be settled by delivery of such securities, in cash or otherwise, or (c) public announcement of any intention to effect any transaction specified in clause (a) or (b). 

13. This Letter Agreement constitutes the entire agreement and understanding of the parties hereto in respect of the subject matter hereof and
supersedes all prior understandings, agreements, or representations by or among the parties hereto, written or oral, to the extent they relate in any way to the subject matter hereof or the transactions contemplated hereby. This Letter Agreement may
not be changed, amended, modified or waived (other than to correct a typographical error) as to any particular provision, except by a written instrument executed by all parties hereto. 

14. No party hereto may assign either this Letter Agreement or any of its rights, interests, or obligations hereunder without the prior written
consent of the other party. Any purported assignment in violation of this paragraph shall be void and ineffectual and shall not operate to transfer or assign any interest or title to the purported assignee. This Letter Agreement shall be binding on
the Sponsor and each Insider and their respective successors, heirs and assigns and permitted transferees. 
 15. This Letter Agreement shall
be governed by and construed and enforced in accordance with the laws of the State of New York, without giving effect to conflicts of law principles that would result in the application of the substantive laws of another jurisdiction. The parties
hereto (i) all agree that any action, proceeding, claim or dispute arising out of, or relating in any way to, this Letter Agreement shall be brought and enforced in the courts of New York City, in the State of New York, and irrevocably submit
to such jurisdiction and venue, which jurisdiction and venue shall be exclusive and (ii) waive any objection to such exclusive jurisdiction and venue or that such courts represent an inconvenient forum. 

16. Any notice, consent or request to be given in connection with any of the terms or provisions of this Letter Agreement shall be in writing
and shall be sent by express mail or similar private courier service, by certified mail (return receipt requested), by hand delivery or facsimile transmission. 

17. This Letter Agreement shall terminate on the earlier of (i) the expiration of the Lock-up
Periods or (ii) the liquidation of the Company; provided further that paragraph 5 of this Letter Agreement shall survive such liquidation. 

[Signature Page Follows] 

  
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	Sincerely,
	
	JUNIPER II MANAGEMENT, LLC
		
	By:	 	 /s/ Roger Fradin

	Name: Roger Fradin
	Title: Manager
		
	By:	 	 /s/ Roger Fradin

		 	Roger Fradin
		 	
	By:	 	 /s/ Mitchell Jacobson

		 	Mitchell Jacobson
		 	
	By:	 	 /s/ Mark Levy

		 	Mark Levy
		 	
	By:	 	 /s/ Noah Kindler

		 	Noah Kindler
		 	
	By:	 	 /s/ Murray Grainger

		 	Murray Grainger
		 	
	By:	 	 /s/ Andrew Teich

		 	Andrew Teich


  

			
	Acknowledged and Agreed:
	
	JUNIPER II CORP.
		
	By:	 	 /s/ Noah Kindler

	Name:	 	Noah Kindler
	Title:	 	Chief Financial Officer and
		 	Chief Technology Officer

 [Signature Page to Letter Agreement]