Interop is a yearly list of web features the browser makers agree to make work the same way. Baseline is the separate label that tells you when they have.
Every year the interop list gets screenshotted and passed around as a shipping list. It is not one. Four features on this year's list look like they delete code your design system hand-rolled. Tooltip positioning, colour pairing tables, tooltip dismiss logic, page transition scripts.
I checked all four this morning. One is Baseline. Three are not, and they fail in different enough ways that one rule for all of them would be wrong.
A place on the interop list is a promise to fix something this year. It is not a report that it works.
The four, checked this morning
For each one: the code you were hoping to delete, where it actually stands, and what to do about it this quarter.
1. contrast-color() is the one that is ready
What you would delete: the table where you hand-pair a text colour to every brand colour, and the audit that keeps that table honest.
Where it stands: Baseline newly available since 10 April 2026. Safari 26, Firefox 146, Chrome and Edge 147. Every core browser passes the whole test suite.
Do this: use it, and leave a plain colour declaration on the line above as the fallback. Newly available means it landed six months ago, not that everyone has updated. Two lines still beats a table.
2. popover="hint" has no Safari
What you would delete: the tooltip code that fights with your open menu.
Where it stands: Firefox shipped it on 21 July 2026 and Chrome and Edge followed a week later. Safari has not shipped it at all, so Baseline says limited.
Do this: keep your current tooltip as the floor and add the attribute as an upgrade. A tooltip that closes the menu underneath it is a bug in Safari, not a softer version of the feature.
3. Anchor positioning is the most wanted and the least ready
What you would delete: the script that positions every dropdown, tooltip and popover you own.
Where it stands: Safari 27 shipped it on 14 September 2026. Chrome and Edge pass over 95% of the test suite and Firefox about 85%. It carried over from last year's list, and 262 developers have upvoted a request for it.
Do this: keep the script. Put the CSS behind a support check and let it take the cases it handles. Deleting the fallback is the expensive mistake here, because a badly placed menu is visible on every screen.
4. Cross-document view transitions are fine to ship anyway
What you would delete: the script that fakes a transition between two pages.
Where it stands: Chrome 126 in June 2024 and Safari 18.2 that December. Firefox passes under 2% of the tests. Over two years old and still limited.
Do this: ship it. This is the one case where the gap costs nothing, because a browser without it simply loads the next page. Just never let the animation carry meaning the page needs.
The four, in one table
| Feature | Baseline today | Use it now? | The catch |
|---|---|---|---|
| contrast-color() | Newly available, April 2026 | Yes | Keep one fallback line above it |
| popover="hint" | Limited | Only as an upgrade | Safari has not shipped it |
| Anchor positioning | Limited | Behind a support check | Firefox is still partial |
| Cross-document view transitions | Limited | Yes | Firefox just loads the page |
The audit
Open the file where your tokens or your tooltips live and find the oldest workaround in it.
Then ask one question. Did I keep this because a browser still needs it, or because it was already there? Check the second kind against Baseline, not against the interop list.
One of those two tells you a browser shipped something. The other tells you someone intends to.
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