SvelteKit config in vite.config, explicit env vars and new declaration tag support across the toolchain

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July 2026 brings significant changes to the SvelteKit ecosystem. The headline feature is the ability to define SvelteKit config directly inside vite.config.js, eliminating the need for a separate svelte.config.js — a preview of how Kit 3 will work. Experimental explicit environment variables are also introduced as a future replacement for $env/* modules. Remote functions gain File object support for uploads and cross-query refresh capabilities. The sv CLI and language tools (svelte-language-server, svelte-check, svelte2tsx) now fully support Svelte 5's {const ...} declaration tags. svelte-check gains experimental tsgo (TypeScript Go) support for faster type checking. The community showcase includes new UI libraries, frameworks, and apps built with Svelte.

What’s new in Svelte: July 2026

What's new in the Svelte CLI and Language Tools

Wait, why did you make this change: <a href="https://svelte.dev/docs/kit/environment-variables#Explicit-environment-variables" target="_blank" rel="noopener nofollow">https://svelte.dev/docs/kit/environment-variables#Explicit-environment-variables </a>?
I see no issues in the previous “standard” solution, so what’s the reason behind it? Now we just have to gitignore <code>src/env.ts</code>?

The <code>tsgo</code> (TypeScript Go) support in <code>svelte-check</code> is the sleeper hit of this release. For large SvelteKit codebases, type checking can take 10-30 seconds in CI. Moving that to a Go-based implementation (leveraging the same work the TypeScript team has been doing) could cut that time by 50-80%. This is a massive quality-of-life improvement for teams running <code>svelte-check</code> on every commit. The File object support for remote functions is also a nice addition—file uploads have always been a pain point in RPC-style frameworks, and this makes them significantly more ergonomic.