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                            April 10, 2023

       Sean Wirtjes
       Chief Financial Officer
       Rapid Micro Biosystems, Inc.
       1001 Pawtucket Boulevard West, Suite 280
       Lowell, MA 01854

                                                        Re: Rapid Micro
Biosystems, Inc.
                                                            Form 10-K for the
fiscal year ended December 31, 2022
                                                            Filed March 10,
2023
                                                            File No. 001-40592

       Dear Sean Wirtjes:

              We have limited our review of your filing to the financial
statements and related
       disclosures and have the following comments. In some of our comments, we
may ask you to
       provide us with information so we may better understand your disclosure.

              Please respond to these comments within ten business days by
providing the requested
       information or advise us as soon as possible when you will respond. If
you do not believe our
       comments apply to your facts and circumstances, please tell us why in
your response.

                                                        After reviewing your
response to these comments, we may have additional comments.

       Form 10-K for the fiscal year ended December 31, 2022

       Item 7. Management's Discussion and Analysis of Financial Condition and
Results of Operations
       Key business metrics, page 64

   1.                                                   On page 65 you set
forth that validation of a system takes anywhere from three to nine
                                                        months and on page 70
you reference the impact to validation from coronavirus. Based
                                                        on the table, it
appears that a number of systems placed in 2021 were not validated as of
                                                        December 31, 2022. As
it relates to these 2021 systems, please describe for us in further
                                                        detail:
                                                            the reasons for any
systems that were placed in 2021 and not validated as of
                                                            December 31, 2022;
                                                            the date revenue
was recognized and the date the system was ultimately validated, for
                                                            each of these 2021
systems;
                                                            how the Growth
Direct system is fully functional for use by the customer upon
                                                            delivery without
validation services, as set forth on page 66;
 Sean Wirtjes
FirstName   LastNameSean   Wirtjes
Rapid Micro   Biosystems, Inc.
Comapany
April       NameRapid Micro Biosystems, Inc.
       10, 2023
April 210, 2023 Page 2
Page
FirstName LastName
                whether these 2021 systems outlined in the table were in actual
use prior to being
              validated;
                how you considered the guidance in ASC 606-10-25-21(c) in the
accounting for your
              systems; and
                the significant terms of your 2021 arrangements. Provide us a
copy of your actual
              2021 contractual arrangement.
Item 15. Exhibits 32.1 and 32.2, page 80

2.       We note that your certifications filed as Exhibits 31.1 and 31.2 do
not
         include paragraph 4(b) and the introductory language in paragraph 4
referring to internal
         control over financial reporting. Please file an amendment to your
annual report that
         includes certifications that conform exactly to the language set forth
within the Exchange
         Act Rule 13a-14(a). Please note that you may file an abbreviated
amendment that consists
         of a cover page, explanatory note, signature page, and paragraphs 1,
2, 4, and 5 of the
         certification.
Consolidated Financial Statements
Revenue Recognition, page F-14

3.       We note your contracts may include multiple performance obligations.
Please revise your
         revenue recognition disclosure in future filings so that users can
understand any impact
         between recurring and non-recurring revenues from your allocation of
the transaction
         price. In this regard, please disclose the qualitative and
quantitative information about the
         significant judgments, and changes in judgments, that significantly
affect the
         determination of the amount and timing of revenue, as set forth in ASC
606-10-50-1(b)
         and 606-10-50-17(b). Please provide us any proposed disclosure.
4.       We note payment terms for customer orders are typically between 30 to
90 days after the
         shipment or delivery of the product. Please clarify for us and in
future filings whether
         these are the payments terms for all performance elements in a
multiple element
         arrangement. Refer to ASC 606-10-50-12(b).
5.       Please clarify for us and in future filings whether your consideration
is variable as set
         forth in ASC 606-10-32-5 through 32-9 and whether your estimate of
variable
         consideration is typically constrained in accordance with paragraphs
ASC 606-10-32-11
         through 32-13. Refer to ASC 606-10-50-12(b) for the required
disclosure.
       In closing, we remind you that the company and its management are
responsible for the
accuracy and adequacy of their disclosures, notwithstanding any review,
comments, action or
absence of action by the staff.
 Sean Wirtjes
Rapid Micro Biosystems, Inc.
April 10, 2023
Page 3

        You may contact Michael Fay at 202-551-3812 or Brian Cascio, Accounting
Branch
Chief, at 202-551-3676 with any questions.



                                                        Sincerely,
FirstName LastNameSean Wirtjes
                                                        Division of Corporation
Finance
Comapany NameRapid Micro Biosystems, Inc.
                                                        Office of Industrial
Applications and
April 10, 2023 Page 3                                   Services
FirstName LastName