Svelte 5+

Drop-in replacement.
Native speed.

Rust parser + parallel transforms + tsgo type-checking. Same CLI. Same output. Faster feedback.


                $npm install -D svelte-check-rs

svelte-check

svelte-check-rs

faster

Built for agentic coding

svelte-check is built on Language Server Protocol infrastructure—optimized for IDEs with persistent connections, incremental updates, and interactive editing. Great for autocomplete and hover info. Slow for one-shot CLI checks.

svelte-check-rs is a batch-first CLI. No LSP. No language service overhead. Just fast, parallel diagnostics for CI pipelines and AI coding agents.

Built for

AI coding agents (Claude Code, Codex, Cursor)
CI/CD pipelines
Pre-commit hooks
Watch mode iteration

Not a replacement for

In-editor diagnostics
Autocomplete / IntelliSense
Hover documentation
Go-to-definition

Keep using the Svelte VS Code extension for IDE features. Use svelte-check-rs when you need fast CLI feedback. Still on Svelte 4? Stick with svelte-check.

Why it's fast

svelte-check

Uses TypeScript's Language Service API with in-memory transforms. Designed for IDEs, not batch compilation. No incremental builds—re-analyzes entire project every run.

svelte-check-rs

Writes real TypeScript files to disk, runs tsgo as a standalone compiler. Enables incremental: true with persistent .tsbuildinfo. Subsequent runs only re-check changed files.

Rust Parser

Zero-copy lexer and AST built for Svelte 5 runes. No Node.js startup overhead.

Parallel Transform

Svelte to TypeScript via rayon. All CPU cores. Source maps preserved.

tsgo Compiler

Microsoft's native Go port of TypeScript. 10x faster than tsc.

Install

npm (recommended)


                $npm install -D svelte-check-rs

macOS / Linux


                $curl --proto '=https' --tlsv1.2 -LsSf https://github.com/pheuter/svelte-check-rs/releases/latest/download/svelte-check-rs-installer.sh | sh

Windows (PowerShell)


                >irm https://github.com/pheuter/svelte-check-rs/releases/latest/download/svelte-check-rs-installer.ps1 | iex

Replace existing scripts

// package.json
{
  "scripts": {
    "check": "svelte-check-rs"
  }
}

Or alias for zero-config switch


                $alias svelte-check=svelte-check-rs

CLI Reference

Core

--workspace <path> Project root

--tsconfig <path> TypeScript config

--output <fmt> human | json | machine

--watch Re-check on file change

Diagnostics

--diagnostic-sources js,svelte,css

--threshold error | warning

--fail-on-warnings Exit 1 on warnings

--ignore <glob> Skip matching files

--debug-paths Show resolved binaries

Performance

--timings Print timing breakdown

--timings-format text | json

--emit-ts Debug: print transformed TS

tsgo

--tsgo-version Show installed tsgo version

--tsgo-update Update tsgo to latest

--tsgo-update=<ver> Install specific version

Scenario	svelte-check	svelte-check-rs	Speedup
Cold start
Warm cache
Iterative

Drop-in replacement.Native speed.