Uploaded December 2025 | Updated September 2026, 3 weeks ago
Santa's Christmas countdown app looks perfect until the page loads and the time flickers — the server in San Francisco says one thing, the client in your timezone says another. The hydratable API fixes this by letting the server's computed value carry over during hydration, keeping everything in sync. Even better, it works with promises: fetch data on the server and the client receives it ready to use without making a second request. This low-level API powers SvelteKit's remote functions under the hood, and now you can use it directly for special cases. Have a happy Christmas, and thank you for following along with Advent of Svelte!
Read the docs: https://svelte.dev/docs/svelte/hydratable
Santa's Christmas countdown app looks perfect until the page loads and the time flickers — the server in San Francisco says one thing, the client in your timezone says another. The hydratable API fixes this by letting the server's computed value carry over during hydration, keeping everything in sync. Even better, it works with promises: fetch data on the server and the client receives it ready to use without making a second request. This low-level API powers SvelteKit's remote functions under the hood, and now you can use it directly for special cases. Have a happy Christmas, and thank you for following along with Advent of Svelte!
Read the docs: https://svelte.dev/docs/svelte/hydratable
