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Ecma TC39

Ecma International, Technical Committee 39 - ECMAScript

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TC39

Ecma International's TC39 is a group of JavaScript developers, implementers, academics, and more, collaborating with the community to maintain and evolve the definition of JavaScript.

Contribute

TC39 welcomes contributions from the JavaScript community, whether it is feedback on existing proposals, improved documentation, testing, implementations, or even language feature ideas. See our contributor guide for details.

Important

To participate in TC39 meetings as a member, join Ecma.

Specifications

We develop the JavaScript (formally, ECMAScript) specification, the Internationalization API specification, the Source Map specification, and, of course, JSON! We meet every two months to discuss proposals. To learn more about the process, please take a look at the six stages for new language feature proposals. See our meeting agendas and minutes to learn more.

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  1. ecma262 ecma262 Public

    Status, process, and documents for ECMA-262

    HTML 15.7k 1.4k

  2. ecma402 ecma402 Public

    Status, process, and documents for ECMA 402

    HTML 610 120

  3. test262 test262 Public

    Official ECMAScript Conformance Test Suite

    JavaScript 2.8k 565

  4. proposals proposals Public

    Tracking ECMAScript Proposals

    19.2k 749

  5. agendas agendas Public

    TC39 meeting agendas

    JavaScript 1.2k 202

  6. notes notes Public

    TC39 meeting notes

    JavaScript 715 131

Repositories

Showing 10 of 337 repositories
  • ecma262 Public

    Status, process, and documents for ECMA-262

    tc39/ecma262's past year of commit activity
    HTML 15,693 1,432 354 (8 issues need help) 124 Updated Sep 23, 2026
  • agendas Public

    TC39 meeting agendas

    tc39/agendas's past year of commit activity
    JavaScript 1,174 202 1 3 Updated Sep 23, 2026
  • tc39/proposal-deferred-reexports's past year of commit activity
    61 MIT 7 8 3 Updated Sep 23, 2026
  • ecma402 Public

    Status, process, and documents for ECMA 402

    tc39/ecma402's past year of commit activity
    HTML 610 120 171 18 Updated Sep 23, 2026
  • proposal-amount Public

    Numbers with precision and a unit for JavaScript

    tc39/proposal-amount's past year of commit activity
    HTML 58 MIT 12 46 6 Updated Sep 23, 2026
  • ecma404 Public

    Status, process, and documents for ECMA 404

    tc39/ecma404's past year of commit activity
    HTML 2 2 0 0 Updated Sep 23, 2026
  • dataset Public

    The automatic track tc39 proposals

    tc39/dataset's past year of commit activity
    TypeScript 50 Unlicense 14 2 0 Updated Sep 23, 2026
  • ecmarkup Public

    An HTML superset/Markdown subset source format for ECMAScript and related specifications

    tc39/ecmarkup's past year of commit activity
    TypeScript 245 MIT 80 100 19 Updated Sep 22, 2026
  • tc39.github.io Public

    Get involved in specifying JavaScript

    tc39/tc39.github.io's past year of commit activity
    HTML 336 MIT 63 27 (2 issues need help) 5 Updated Sep 22, 2026
  • data Public

    TC39's source of truth for programmatically available process/proposal data.

    tc39/data's past year of commit activity
    JavaScript 1 MIT 0 0 1 Updated Sep 22, 2026