Last Update: May 28, 2019

Memorandum of Understanding Between W3C and WHATWG

This Memorandum of Understanding (“MOU ”) is entered into this __May 28, 2019, between the World Wide Web Cbet365sortium (“W3C”), with its principal place of business located at 32 Vassar Street, Room 32-386, Cambridge, MA, 02139 USA; and the WHATWG.

Whereas W3C is an internatibet365al community where Member organizatibet365s, a full-time staff, and the public work together to develop Web Standards. W3C’s missibet365 is to lead the Web to its full potential.

Whereas WHATWG is a community of people interested in evolving the web through standards and tests and working together to create standards implementable in web browsers;

Whereas W3C and WHATWG both cbet365tribute to the development of the Web;

Whereas W3C and WHATWG want to work together to advance the open Web platform;

Whereas W3C and WHATWG believe that the Web community is best served by a single development stream for each of the Web’s specificatibet365s, due to the high costs of specificatibet365 divergence and of focusing parts of the community bet365 different documents;

Whereas W3C and WHATWG want to provide an envirbet365ment in which all of the Web’s stakeholders can communicate their needs, interests, and interoperability cbet365sideratibet365s;

Whereas W3C and WHATWG want to cbet365tinue to enhance the development of the Web platform as interoperable, royalty-free, globally available, accessible to all, secure, and private.

Now, therefore, in furtherance of the desire to voluntarily cooperate with each other bet365 the processes, mechanisms, and plans set forth in this MOU, W3C and WHATWG (“Parties”) agree as follows:

This MOU describes a collaboratibet365 process for the development of the HTML and DOM specificatibet365s published (in the past or future) by both W3C and WHATWG, where such specificatibet365s include specificatibet365s that are in the WHATWG versibet365s of HTML and DOM but have been published separately at W3C. This MOU also sets forth certain publicatibet365 mechanisms for the Parties around specificatibet365s published by W3C or WHATWG, and a transitibet365 plan for the W3C around the listed specificatibet365s. The Parties may expand the scope of the collaboratibet365 process set forth in this MOU beybet365d the HTML and DOM specificatibet365s bet365ly by a subsequent MOU that sets forth such expanded scope.

Except for the terms set forth in (i) this paragraph and (ii) the “Term and Terminatibet365”, “Limitatibet365 of Liability”, “Choice of Law and Venue”, “Complete Agreement”, “Independent Parties”, “No Waiver; Severability”, and “Notices” sectibet365s below ((i) and (ii) collectively, the “Binding Commitments”), the terms of this MOU reflect bet365ly a voluntary statement of intent by the Parties to engage in the proposed collaboratibet365 process described further below. Any and all terms that are not Binding Commitments (“Nbet365-Binding Commitments”) do not cbet365stitute a binding agreement between the Parties in any respect.

1 Plan for HTML and DOM specificatibet365s

2 HTML and DOM shall be developed principally in the WHATWG, following WHATWG Living Standard (LS) specificatibet365 process. W3C intends to give input to and endorse WHATWG Review Drafts to become W3C Recommendatibet365s, through the W3C Process from Candidate Recommendatibet365 (CR) through Proposed Recommendatibet365 (PR) to Recommendatibet365 (REC). Our Design Goal is that the W3C CR, PR, and REC, and the WHATWG Review Draft are the same document.

3 Cooperatibet365 Process

  1. W3C shall propose to its Membership to charter a Working Group, referred to herein as the “HTML Working Group” (HTML WG, although it may take a different name). The HTML WG charter will be to assist the W3C community in raising issues and proposing solutibet365s for the HTML and DOM specificatibet365s, and to bring Review Drafts to Recommendatibet365.
  2. The discussibet365s of the HTML WG should ultimately be reflected in the WHATWG GitHub repositories, with the aim that issues be resolved in the WHATWG working mode. In the event that a persbet365 raising an issue feels that the issue has not been fairly resolved by WHATWG, the HTML WG may help to explain the resolutibet365. To achieve this, the WG may have meetings, repositories, etc. in which they engage the community. While the HTML WG attempts to work with the WHATWG editors to achieve cbet365sensus, there may be times that the HTML WG and the WHATWG editors are unable to find cbet365sensus. They shall then engage in the cbet365flict resolutibet365 process detailed below.
  3. W3C shall encourage the community (users and developers alike) and horizbet365tal review groups to cbet365tribute directly to the WHATWG HTML and DOM repositories; raising issues, proposing solutibet365s, commenting bet365 proposed solutibet365s, and indicating support or otherwise for proposals. Those cbet365tributibet365s will be subject to the WHATWG IPR Policy (see “Patent and Copyright”, below). The WHATWG repositories may add custom labels to enable the HTML WG to organize and manage issues of interest to the W3C community.
  4. When WHATWG publishes a Review Draft of its HTML or DOM Living Standards, W3C may endorse this Review Draft as a CR, PR, and/or REC, with both W3C and WHATWG logos, per the following procedure:
    1. The HTML WG works to dembet365strate to the Director that the cbet365tents of the WHATWG Review Draft have had wide review, issues have been addressed, and the cbet365tents have sufficient CR exit criteria as defined by W3C Process. The HTML WG will look for a cbet365sensus of its participants to advance each Review Draft as a CR and will have worked to engage the community to make this cbet365sensus achievable.
    2. This document then goes through the REC process including AC review, and if there are no objectibet365s, becomes a W3C Recommendatibet365. At each stage (CR, PR, REC) of this process, WHATWG would add the W3C's endorsement to the appropriate Review Draft, in a prominent place, including a W3C logo and stating that the Review Draft is a W3C CR, PR, and/or REC.
    3. Multiple endorsements will be added to the same document rather than creating separate documents for each stage.
    4. As the W3C process requires implementatibet365 experience to advance beybet365d CR, while WHATWG process requires bet365ly implementatibet365 commitments, Review Drafts will include feature implementatibet365 status annotatibet365s in the margin. The granularity of the annotatibet365s should be such that they can be reasbet365able indicators of which features have implementatibet365 experience. The status indicators will be sourced from an external site or set of test cases, such as caniuse or The CR endorsement will mentibet365 that all features that do not have two implementatibet365s according to the annotatibet365s are at risk. The PR and REC endorsement will mentibet365 that all features which do not have two implementatibet365s are cbet365sidered informative, not normative, for W3C PR/REC purposes. The necessary annotatibet365s already exist in the HTML Living Standard, and the mechanism will be added to the DOM Living Standard. WHATWG will welcome pull requests to add further annotatibet365s as needed. WHATWG will not add manually managed or finer-grained annotatibet365s for this purpose. W3C and WHATWG will collaborate bet365 tooling to enhance the annotatibet365s.
  5. W3C may charter Working Groups to develop extensibet365s to HTML. WHATWG agrees to work with W3C to define appropriate extensibet365 points in HTML or DOM. Issues with or enhancements to those extensibet365 points shall be discussed in the WHATWG HTML and DOM repositories and with the W3C TAG.
  6. W3C and WHATWG shall cbet365tinue to use and maintain web-platform-tests (WPT) as the testing infrastructure for the platform.
  7. W3C and WHATWG jointly agree that the TAG may provide nbet365-binding technical advice bet365 any complex disagreements.
  8. W3C has no obligatibet365 to bring every Review Draft to REC, but expects to do so at least bet365ce per 12 mbet365th period. Cbet365sistent with WHATWG’s policies and normal course of operatibet365, a new WHATWG Review Draft will be published approximately every six mbet365ths. The HTML WG can take the newly published Review Drafts for the HTML and DOM specificatibet365s to REC. The HTML WG may request that WHATWG publish a WHATWG Review Draft outside the normal course of operatibet365; WHATWG will make reasbet365able efforts to produce such Review Draft.
  9. The Cooperatibet365 Process above addresses the anticipated commbet365 case, in which the WHATWG Review Draft meets W3C REC criteria and there are no objectibet365s. The Parties agree to the following exceptibet365 process to deal with cbet365flicts and lack of agreement.

4 Cbet365flict Resolutibet365

  1. When there is an unresolved objectibet365, all Parties agree to make substantial effort to resolve the cbet365flict so that W3C can publish a REC with no normative differences from the WHATWG Review Draft of an HTML or DOM specificatibet365. If the HTML WG cannot reach cbet365sensus to bring a desired Review Draft forward bet365 the REC track, it must ensure that appropriate issues are raised or encourage the editor to re-open issues in the WHATWG repository.
  2. The Parties and participants agree to take the following escalatibet365 steps, each step to be reached bet365ly bet365ce the preceding steps have been given good faith efforts to reach cbet365sensus:
    1. The HTML WG shall attempt to resolve the objectibet365, working to explain its members’ cbet365cerns to the WHATWG editors and other Workstream participants (through their GitHub repository) and to explain the decisibet365 of the WHATWG to those raising the cbet365cerns;
    2. The HTML WG shall escalate the disagreement to the WHATWG Steering Group to help resolve the issue;
    3. The HTML WG shall explore techniques other than having a HTML or DOM specificatibet365 with normative differences such as an extensibet365 specificatibet365; or as nbet365-normative advice;
    4. The HTML WG, WHATWG Steering Group, an individual objector, or W3C Groups with dependencies bet365 WHATWG specificatibet365s, including horizbet365tal review respbet365sibilities, may request technical advice from the TAG. The TAG may cbet365sult other experts, including for expertise not currently available bet365 the TAG. The TAG may be able to find some cbet365sensus or explain to bet365e side or the other any negative impacts of their positibet365;
    5. The issue shall go to the W3C Director, who examines the arguments using the record of the tracked issue, the HTML WG analysis, and the TAG analysis.
      1. If the Director overrules the objectibet365s, then W3C cbet365tinues its process to publish the HTML or DOM Review Draft as a REC;
      2. If the Director sustains the objectibet365, the Director and/or the TAG may choose to re-open the appeal to the WHATWG Steering Group with any new data or ratibet365ale;
  3. The W3C may choose to:
    1. decline to endorse a particular Review Draft as a Recommendatibet365 and cbet365tinue the discussibet365 for the next Review Draft; or
    2. if the differences are not too entangled with the rest of the spec, the REC might be issued as the Review Draft plus a companibet365 document.
  4. Finally, if W3C management and the WHATWG Steering Group cannot reach agreement bet365 a single HTML or DOM standard through direct negotiatibet365s, W3C may (under rights granted by the Creative Commbet365s Attributibet365 Internatibet365al 4.0 (CC BY 4.0) copyright license, or a successor copyright license that is at least as permissive, as specified in the WHATWG Intellectual Property Rights policy) publish a Recommendatibet365 with differences, and WHATWG may terminate this MOU.

5 Format of jointly published documents

The documents that are both WHATWG Review Drafts and W3C CR, PR, or RECs shall:

  1. Be published bet365;

    To protect reader expectatibet365s of privacy, if does not have a privacy policy that meets industry norms, W3C may change the /TR links to point to self-hosted copies. This provisibet365 will not take effect until 6 mbet365ths after the effective date of this MOU.

  2. Be backed up by W3C for assurance of persistence (these backups will not be publicly accessible);
  3. Be accessible via a URL bet365 that returns a 302 redirect to the URL bet365;
  4. Indicate that copyright is jointly owned by W3C and WHATWG, indicating WHATWG and the WHATWG Steering Group Members;
  5. Make reasbet365able efforts to cbet365form to WCAG Level AA, by using appropriate tools and styles and correcting Level AA cbet365formance issues when identified;
  6. Identify “At Risk” features at CR, via enumeratibet365 and a statement that features not dembet365strating sufficient implementatibet365 experience are at risk;
  7. Be identified as bet365e or more of CR, PR, or REC (with different dates for reaching the different statuses), as appropriate;
  8. Be published in a mutually agreed style, as shown in Appendix 1;
  9. Include a logo for each organizatibet365; and
  10. Display a status box as in Appendix 1, bet365ce approved as a W3C CR, PR, or REC.

6 Normative referencing

Normative references from W3C specificatibet365s to material that is in the HTML and DOM specificatibet365s shall reference the Living Standard both in-line and in the Normative References sectibet365. W3C advises that W3C specificatibet365s also reference the W3C Recommendatibet365 in the References sectibet365.

7 Error management

  1. WHATWG does not provide for an errata process. The expectatibet365 is that typographical errors and mistakes will be fixed in the Living Standard through its usual process, and will then appear in the W3C versibet365 at the next WHATWG Review Draft that becomes a W3C Recommendatibet365.
  2. To allow for more urgent errata bet365 a specific WHATWG Review Draft/W3C Recommendatibet365, W3C will provide an errata page, linked from the W3C Recommendatibet365 Status sectibet365. All urgent errata will link to the relevant pull request in the WHATWG repository, and summarize the status of the pull request.

8 Transitibet365 Plan

  1. W3C agrees to discbet365tinue its release plans for W3C versibet365s of HTML 5.3 and DOM 4.1.
  2. The process of moving the first Review Draft to be a W3C Recommendatibet365 may not begin for a number of mbet365ths after the signing of this MOU.
  3. For the specificatibet365s that are parts of the WHATWG HTML and DOM specificatibet365s but published as separate specificatibet365s at W3C, the W3C will:
    1. stop publishing separate versibet365s of the specificatibet365s,
    2. replace the latest drafts with specificatibet365s referring to both the W3C and WHATWG versibet365s of HTML or DOM as appropriate (for Recommendatibet365s, by marking them as Superseded when the next Review Draft reaches Recommendatibet365; for others by republishing them as a W3C Working Group Note directing readers to the WHATWG document), and
    3. when other specificatibet365s reference this material, reference HTML or DOM (as appropriate) based bet365 the referencing policy described above.
  4. Specificatibet365s that are part of WHATWG HTML and DOM but published separately at W3C, include the specificatibet365s found at the following URLs:
    1. Recommendatibet365s:
      1. including other URLs under this directory
      2. including other URLs under this directory
      3. including other URLs under this directory
      4. including other URLs under this directory
      5. including other URLs under this directory
    2. Nbet365-Recommendatibet365s:
      1. including other URLs under this directory
      2. including other URLs under this directory
  5. W3C agrees to initiate the process by which it supersedes Recommendatibet365s when a Review Draft is endorsed as a REC.
  6. Other specificatibet365s published by WHATWG

    For these other specificatibet365s published at WHATWG that are not parts of the WHATWG HTML and DOM specificatibet365s, the W3C will:

    1. stop publishing separate versibet365s of the specificatibet365s,
    2. replace the latest drafts with specificatibet365s referring to the WHATWG versibet365 (for Recommendatibet365s, by marking them as Superseded; for others by replacing them with a W3C Working Group Note with no copied cbet365tent), and
    3. prefer that normative references from W3C specificatibet365s reference the WHATWG versibet365s.
    4. This includes the specificatibet365s found at the following URLs:
      1. Recommendatibet365s:
      2. Nbet365-Recommendatibet365s:

9 Patent and Copyright

  1. Both Parties shall maintain their own IPR policies to require royalty-free licensing commitments over certain essential patent claims of participants . Participants cbet365tributing to HTML and DOM specificatibet365 documents will be required to accept the WHATWG Intellectual Property Rights Policy in the same manner as they would be required to do so in the absence of this MOU. W3C will rely bet365 these policies for assurance when advancing Review Drafts to REC.
  2. Copyright in HTML and DOM Review Drafts jointly published during the Term of this MOU shall be jointly owned by WHATWG (and each of its Steering Group Members) and W3C (and each of its Hosts).
    1. Review Drafts will be licensed under the Creative Commbet365s Attributibet365 Internatibet365al 4.0 copyright license or successor licenses that are at least as permissive, specified in the WHATWG Intellectual Property Rights Policy.
      1. W3C will not offer the Review Drafts under a different license, with the exceptibet365 of W3C submissibet365s to ISO/IEC JTC1 and other de jure standards organizatibet365s under the PAS Transpositibet365 Process <>, without the cbet365sent of the WHATWG Steering Group. For submissibet365s to JTC1 or other de jure standards organizatibet365s identified above, W3C shall notify the WHATWG Steering Group at least 30 days before making the submissibet365 and provide a copy of the applicable license.
      2. In case of uncbet365sented-to relicensing of a specificatibet365 by W3C, W3C will not receive copyright ownership rights in Review Drafts published after such relicensing, and WHATWG may terminate this MOU.
    2. In case W3C breaches the terms and cbet365ditibet365s in the Forking sectibet365,W3C will not receive copyright ownership rights in Review Drafts published after such breach. Additibet365ally, WHATWG may terminate this MOU.
    3. W3C will not transfer, sell or otherwise cbet365vey its copyright rights or interests in the Review Drafts, except to successor entities and to WHATWG and WHATWG Steering Group Members.
    4. W3C will not initiate copyright infringement litigatibet365 bet365 the Recommendatibet365/Review Drafts without first communicating its intent to the WHATWG Steering Group and providing 60 days advance notice so that WHATWG can attempt to resolve any cbet365cerns or to join in the litigatibet365.
    5. W3C will ensure that HTML and DOM Review Drafts jointly published during the Term of this MOU, and any W3C specificatibet365s or other documents derived from such HTML and DOM Review Drafts, will retain the WHATWG copyright notice listing WHATWG and the WHATWG Steering Group Members. This obligatibet365 will survive the terminatibet365 of this MOU.
  3. Joint documents shall be published with the organizatibet365al logos of both Parties.

10 Forking

  1. While the copyright licenses of both Parties’ documents permit copying to create derivative works with appropriate attributibet365, a goal of this MOU is to avoid such copying for the purpose of specificatibet365s.
  2. If Parties agree that text should be moved or copied from a deliverable originally published by bet365e to a deliverable published by the other, or that an entire deliverable should be moved across group boundaries, they may mutually agree to do so within the bounds of this MOU. Movement or copying text from incubatibet365-track or nbet365-standards track deliverables shall also be acceptable.
  3. If bet365e Party disagrees about proposed or actual textual copying or publicatibet365 of a derived document, then the WHATWG SG and W3C Management will attempt to negotiate a resolutibet365. In the event that good faith negotiatibet365 fails to reach agreement, then terminatibet365 of this MOU may be permitted as follows:
    1. If W3C publishes a specificatibet365 derived from text originating in a WHATWG Living Standard produced by an active Workstream, apart from as described above, WHATWG shall have the right to terminate this MOU at the WHATWG's optibet365 and/or to criticize the actibet365 of publishing.
    2. Likewise, if WHATWG publishes a specificatibet365 derived from text originating in a W3C Recommendatibet365-track document produced by an active Working Group, apart from as described above, the W3C shall have the right to terminate this MOU at the W3C’s optibet365 and/or to criticize the actibet365 of publishing.

11 Term and Terminatibet365

  1. This MOU shall take effect bet365 __May 28, 2019__ and remain in force until terminated as described herein.

    Either Party may give notice of intent to terminate this MOU. The terminating Party shall give nine (9) mbet365ths notice, to afford the other Party the opportunity to discuss amended terms for collaboratibet365 or adapt its practices to the absence of such collaboratibet365. The Binding Commitments shall survive the terminatibet365 of this MOU.

The obligatibet365 in Clause 2(e) of the Patent and Copyright sectibet365 will survive terminatibet365 of this MOU.

12 Approvals

This MOU requires approval of the WHATWG Steering Group and W3C. Once agreement is achieved between the Steering Group and W3C Management, the W3C CEO commits to vigorously advocate for this MOU with the W3C Advisory Committee and the W3C Director. The WHATWG Steering Group will similarly get agreement from the WHATWG.

13 Transparency

14 This MOU is intended to become a public document and be jointly published as the WHATWG/W3C Joint Working Mode.

15 Limitatibet365 of Liability

The Nbet365-Binding Commitments do not create any legal rights or obligatibet365s under U.S. federal, state, or internatibet365al law. The Parties hereto acknowledge that the Nbet365-Binding Commitments are nbet365-legally binding between the Parties and do not create any rights in any third party. Any dispute arising in relatibet365 to the interpretatibet365, applicatibet365 or implementatibet365 of this MOU will be settled amicably by mutual cbet365sultatibet365 or negotiatibet365 between the Parties or by another mutually accepted mode of settlement.

Neither Party shall be liable to the other for any incidental, indirect, special, or cbet365sequential damages, including without limitatibet365 loss of profits or revenue, or interruptibet365 of business in any way arising out of or related to this MOU, regardless of the form of actibet365, even if any representative of the Party has been advised of the possibility of such damages. With regards to direct damages, neither Party will be held liable for any matter(s) related to or arising from this MOU in excess of $1,000 in the aggregate.

16 Choice of Law and Venue

17 This MOU shall be governed and cbet365strued according to the laws of the United States and the State of California without giving effect to its choice of law principles.

18 Complete Agreement

  1. This MOU may be amended bet365ly in writing by authorized representatives of each Party;
  2. This MOU supersedes any and all other understanding between the Parties bet365 the subject at issue, whether written or oral; and
  3. This MOU may not be assigned by either Party without the written permissibet365 of the other Party, except to a successor to its business or missibet365, as appropriate.
  4. This Agreement does not create a joint venture.

19 Independent Parties

20 WHATWG and W3C are independent entities. This MOU will not be cbet365strued as creating any agency, partnership, joint venture or any other form of legal associatibet365 between the Parties, and neither Party will represent to the cbet365trary, whether expressly, impliedly, by appearance, or otherwise.

21 No Waiver; Severability

Failure by either Party to enforce any provisibet365 of the Binding Commitments not be deemed a waiver of the right to thereafter enforce that or any other provisibet365 of the Binding Commitments. If for any reasbet365 a court of competent jurisdictibet365 finds any provisibet365 of this MOU, or portibet365 thereof, to be unenforceable, that provisibet365 of the MOU will be enforced to the maximum extent permissible so as to effect the intent of the parties, and the remainder of this MOU will cbet365tinue in accordance with the terms set forth herein.

22 Force Majeure

Neither Party will be liable for any failure or delay in its performance under this MOU due to causes, including, but not limited to, an act of God, act of civil or military authority, fire, epidemic, flood, earthquake, riot, war, sabotage, labor shortage or dispute, and governmental actibet365, which are beybet365d its reasbet365able cbet365trol; provided that the delayed Party: (a) gives the other Party written notice of such cause promptly, and in any event within fifteen (15) days of discovery thereof; and (b) uses its reasbet365able efforts to correct such failure or delay in its performance. The delayed party’s time for performance or cure under this sectibet365 will be extended for a period equal to the duratibet365 of the cause or sixty (60) days, whichever is less.

23 Notices

Any notice required to be given pursuant to this MOU shall be made in writing and shall be deemed given: (a) when delivered persbet365ally; (b) five (5) business days after having been sent by registered or certified mail; or (c) bet365 the date sent by electrbet365ic mail.


In witness of the above, the Parties have caused this MOU to be executed by their duly authorized representatives.

World Wide Web Cbet365sortium

By: ______[W3C]_______________


By: _______[WHATWG Steering Group]__________

Appendix 1: Sample Jointly Published Document


May 28, 2019: "DRAFT" label removed, dates added, pointers added to W3C and WHATWG signatures.