August 9, 2019

Olivier Pomel
Chief Executive Officer
Datadog, Inc.
620 8th Avenue, 45th Floor
New York, NY 10018

       Re: Datadog, Inc.
           Amendment No. 1 to Draft Registration Statement on Form S-1
           Submitted July 30, 2019
           CIK No. 0001561550

Dear Mr. Pomel:

      We have reviewed your amended draft registration statement 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 this letter by providing the requested information and
either submitting
an amended draft registration statement or publicly filing your registration
statement on
EDGAR. If you do not believe our comments apply to your facts and circumstances
or do not
believe an amendment is appropriate, please tell us why in your response.

      After reviewing the information you provide in response to these comments
and your
amended draft registration statement or filed registration statement, we may
have additional
comments. References to our prior comments refer to our letter dated July 10,
2019.

Amendment No. 1 to Draft Registration Statement on Form S-1

Management Discussion and Analysis of Financial Condition and Results of
Operations
Factors Affecting Our Performance, page 57

1.     We note your response to prior comment 2. Please explain further your
inclusion of
       additional usage and committed amounts in calculating the monthly
run-rate (MRR). In
       this regard, tell us what each of these represent. With regards to
additional usage, if a
       customer incurs additional usage in a given month and it is included in
your MRR, please
       clarify whether that customer is contractually committed to similar
levels of usage in the
       following months. If not, tell is how you determined that is appropriate
to annualize the
       revenue related to such additional usage in determining your annualized
run-rate.
 Olivier Pomel
Datadog, Inc.
August 9, 2019
Page 2
2.    We note your revised disclosures in response to prior comment 4. Please
clarify why you
      chose to disclose that your dollar-based net retention rate has been over
130% for each of
      the last eight fiscal quarters when it appears that a higher data point
may be more
      relevant. Also, confirm that you intended to refer to a dollar-based net
retention rate of
      146% as of June 30, 2019 and explain why such amount differs from the
supplemental
      information you provided. Lastly, to add context to your current
measures, please revise
      to provide comparative data for each period presented.
3.    Please disclose how you determine the ARR attrition for purposes of
calculating the
      dollar-based gross retention rate.
        You may contact Eiko Yaoita Pyles, Staff Accountant, at (202) 551-3587
or Kathleen
Collins, Accounting Branch Chief, at (202) 551-3499 if you have questions
regarding comments
on the financial statements and related matters. Please contact Edwin Kim,
Staff Attorney, at
(202) 551-3297 or Jan Woo, Legal Branch Chief, at (202) 551-3453 with any other
questions.



                                                           Sincerely,

FirstName LastNameOlivier Pomel                            Division of
Corporation Finance
                                                           Office of
Information Technologies
Comapany NameDatadog, Inc.
                                                           and Services
August 9, 2019 Page 2
cc:       Nicole Brookshire, Esq.
FirstName LastName