CSS Grid Lanes, a new layout tool that simplifies masonry‑style designs, has finally landed in Safari Technology Preview 163. The feature, defined in CSS Grid Layout Level 3, lets developers declare grid‑lanes without JavaScript. Early adopters can experiment now, while other browsers lag behind.

Firefox was first to ship the original proposal in 2020, exposing a masonry flag in Nightly. Safari followed in 2023, enabling the spec by default. Chrome and Edge added a flag in July 2025, but use a different syntax, sparking debate in the CSS Working Group.

Developers can start using Grid Lanes today with progressive enhancement. By wrapping native grid‑lanes in a feature query and falling back to a JavaScript polyfill like Masonry.js, sites deliver fast, CSS‑only layouts to modern browsers while keeping older users functional.

Once all engines ship the spec, developers can drop the polyfill and rely solely on CSS. For now, the key takeaway is that Grid Lanes is already usable in preview browsers, and the community can experiment, report bugs, and prepare production code for the upcoming stable releases.