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How to Apply MDN Baseline Labels for Reliable Web Feature Support

24 February 2026 by
Suraj Barman

Definition of MDN Baseline Labels

MDN Baseline labels identify web platform features that are natively supported in the current two major releases of the major browsers. A feature marked as Baseline can be used in production with confidence that it works across the core browser set.

Core Browser Set

The core browser set defines which browser versions are considered when a feature receives a Baseline label.

  • Two most recent major releases of Firefox, Chrome, Edge and Safari
  • Selection based on global usage statistics and developer expectations
  • Updates automatically as new versions become stable
  • Provides a consistent baseline for libraries and frameworks
  • Ensures that baseline features are widely available to end users

Web Platform Feature Set (WPFS)

The WPFS is a shared vocabulary created by the WebDX Community Group to describe browser capabilities.

  • Each entry contains a unique identifier, description, and support matrix
  • Baseline status is derived from the core browser set criteria
  • Data stored in a public GitHub repository for community contributions
  • Used by MDN to generate feature tables and compatibility badges
  • Facilitates communication between browser vendors and developers

Contribution Workflow

Developers can help keep the feature set current by submitting updates through the official repository.

  • Fork the Feature Set repo on GitHub
  • Update support tables for new browser releases
  • Open a pull request for review by the community group
  • MDN automatically reflects approved changes on its pages
  • Feedback loop encourages accurate baseline labeling

Baseline Impact on Development

Using Baseline labels allows teams to make informed decisions about which APIs to adopt.

  • Reduces time spent testing for edge‑case browser bugs
  • Enables faster feature rollout in production environments
  • Provides clear guidance for polyfill strategy decisions
  • Improves documentation consistency across MDN articles, such as the Web Interoperability guide
  • Reference implementation patterns such as the service‑worker tutorial for offline support