mdn/data

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This repository contains general data for Web technologies

Stars: 787
Forks: 216
Open beginner issues: 0
Indexed issues: 37
Avg merge: 1d 5h
Merged PRs (30d): 6

Dominant language: JavaScript
License: CC0-1.0
Last GitHub push: Sep 18, 2026
Latest indexed: Sep 19, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: help wanted

Beginner friendly Everything

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37 open issues indexed

Computed value for CSS animation's animation-timeline component Open

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

mdn/data#1096 · 1 comment · Opened Jun 9, 2026
`†` in `an+b` definition Open

accepting PR

Difficulty 1/5 Under an hour Newbie friendliness 62/100

mdn/data#1051 · 1 reaction · Opened Mar 5, 2026
`image-set-option` doesn't mark `resolution`/`type` as optional Open

accepting PR

Difficulty 1/5 Under an hour Newbie friendliness 55/100

mdn/data#924 · 1 comment · Opened Feb 9, 2025
Proposal: Support mirroring features Open

idle needs triage

Difficulty 5/5 Over a week Newbie friendliness 35/100

mdn/data#888 · 1 reaction · Opened Jan 7, 2025
Proposal: Remove IE-only features Open

idle

Difficulty 5/5 Over a week Newbie friendliness 25/100

mdn/data#837 · 3 comments · Opened Dec 19, 2024
Proposal: Replace obsolete with deprecated Open

Difficulty 3/5 1-2 days Newbie friendliness 38/100

mdn/data#812 · 1 comment · Opened Dec 2, 2024
Proposal: Repetitive CSS function data between functions.json and syntaxes.json Open

idle p3

Difficulty 3/5 1-2 days Newbie friendliness 38/100

mdn/data#811 · 1 comment · 1 reaction · Opened Dec 2, 2024
Making the CSS property `appliesto` values more specific Open

idle

Difficulty 5/5 Over a week Newbie friendliness 25/100

mdn/data#585 · 9 comments · 5 reactions · Opened Jun 8, 2022
% unit is missing Open

accepting PR

mdn/data#553 · 4 comments · 1 assignee · Opened Feb 9, 2022
Logical properties missing computed values Open

accepting PR

Difficulty 3/5 1-2 days Newbie friendliness 35/100

mdn/data#477 · 9 comments · 1 reaction · Opened Feb 22, 2021
The "better-ajv-errors" package fails to report a schema error Open

idle

Difficulty 3/5 1-2 days Newbie friendliness 35/100

mdn/data#441 · Opened Nov 10, 2020
Breaking changes: scoping the npm package and dropping Node.js < 10 support (RFC for MDN Data 3.0) Open

idle

Difficulty 4/5 3-5 days Newbie friendliness 35/100

mdn/data#427 · 1 reaction · Opened Sep 17, 2020
Full mdn data for browser / javascript apis + html (tags, attributes, events, props) Open

idle

Difficulty 5/5 Over a week Newbie friendliness 25/100

mdn/data#415 · 6 reactions · Opened Mar 27, 2020
Array value for `media` field in properties.json causes `Value not found in DB!` Error Open

idle

Difficulty 4/5 3-5 days Newbie friendliness 25/100

mdn/data#372 · 1 reaction · Opened Jun 10, 2019
Investigate: A JSON file correlating input types to their supported attributes with any useful added data Open

idle

Difficulty 5/5 Over a week Newbie friendliness 25/100

mdn/data#320 · 2 comments · Opened Oct 31, 2018
Missing `-ms-grid-*` properties Open

idle

Difficulty 2/5 1-3 hours Newbie friendliness 42/100

mdn/data#316 · 4 comments · 1 reaction · Opened Oct 22, 2018
Status of dropped-during-experimental-phase elements Open

accepting PR

Difficulty 3/5 1-2 days Newbie friendliness 55/100

mdn/data#315 · 1 comment · Opened Oct 22, 2018
May need updates to DOMTokenList and related interfaces Open

accepting PR

Difficulty 2/5 1-3 hours Newbie friendliness 45/100

mdn/data#306 · 5 comments · Opened Oct 2, 2018
Need Inheritance Data for CSS OM (Houdini) Open

accepting PR

Difficulty 3/5 1-2 days Newbie friendliness 35/100

mdn/data#302 · Opened Sep 27, 2018
Need inheritance data for Sensor APIs Open

accepting PR

Difficulty 2/5 1-3 hours Newbie friendliness 38/100

mdn/data#295 · 1 comment · Opened Sep 13, 2018
Expose short descriptions for CSS properties in mdn/data Open

Epic idle

Difficulty 5/5 Over a week Newbie friendliness 25/100

mdn/data#262 · Opened Aug 16, 2018
CSS items should only belong to a single group Open

idle question

Difficulty 5/5 Over a week Newbie friendliness 25/100

mdn/data#238 · 8 comments · Opened May 29, 2018
Missing font-feature at-rules Open

accepting PR

Difficulty 2/5 1-3 hours Newbie friendliness 45/100

mdn/data#232 · 3 comments · Opened May 23, 2018
Simplify syntaxes Open

idle

Difficulty 4/5 3-5 days Newbie friendliness 35/100

mdn/data#230 · 3 comments · 8 reactions · Opened May 14, 2018
Improvements on at-rule syntax description Open

accepting PR

Difficulty 3/5 1-2 days Newbie friendliness 45/100

mdn/data#222 · 1 comment · Opened May 6, 2018
CSS seems to be missing "speak" Open

accepting PR

Difficulty 3/5 1-2 days Newbie friendliness 35/100

mdn/data#218 · 11 comments · 3 reactions · Opened Apr 30, 2018
Use MDN data to power auto completion in editors through Language Server Protocol Open

enhancement idle

Difficulty 5/5 Over a week Newbie friendliness 25/100

mdn/data#199 · 15 comments · 6 reactions · Opened Apr 9, 2018
Lint sort order of data sheets Open

idle

Difficulty 4/5 3-5 days Newbie friendliness 28/100

mdn/data#197 · 1 comment · Opened Apr 6, 2018
How to represent token types/any-value in the schema Open

idle

Difficulty 5/5 Over a week Newbie friendliness 25/100

mdn/data#190 · Opened Mar 6, 2018
Validate syntaxes Open

help wanted idle

Difficulty 4/5 3-5 days Newbie friendliness 35/100

mdn/data#172 · 2 comments · Opened Feb 7, 2018
(SMIL / begin/end) <begin-value-list>/<syncbase-value> Open

idle

Difficulty 5/5 Over a week Newbie friendliness 20/100

mdn/data#151 · 1 comment · Opened Nov 22, 2017
Attribute support by tag Open

idle

Difficulty 5/5 Over a week Newbie friendliness 25/100

mdn/data#144 · 1 comment · Opened Nov 2, 2017
Consider using shepard (Bikeshed tool) to generate CSS data automatically Open

api css enhancement idle

Difficulty 5/5 Over a week Newbie friendliness 25/100

mdn/data#93 · 2 comments · Opened Jun 20, 2017
Distinguish between simple and complex initial values in data/css/properties.json Open

css help wanted idle

Difficulty 5/5 Over a week Newbie friendliness 25/100

mdn/data#61 · 13 comments · 1 reaction · Opened Apr 28, 2017
Add SVG data Open

idle

Difficulty 4/5 3-5 days Newbie friendliness 38/100

mdn/data#59 · 16 comments · 11 reactions · Opened Apr 6, 2017
Migration Template:SpecName Open

idle

Difficulty 4/5 3-5 days Newbie friendliness 15/100

mdn/data#56 · 1 comment · Opened Mar 30, 2017
Split css/syntaxes.json into several files Open

idle

Difficulty 5/5 Over a week Newbie friendliness 25/100

mdn/data#42 · 1 comment · Opened Jan 31, 2017

mdn/data

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