Dependencies

Active contributors: Rich Harris, Ben McCann, Simon H

Snapshot from packages/svelte/package.json and the top-level package.json. All counts are at the time of this wiki snapshot (commit 572444a69).

Runtime dependencies (packages/svelte)

16 in total. Grouped by purpose:

Package	Used in
acorn	JS/TS parser used by phases/1-parse.
@sveltejs/acorn-typescript	TypeScript plugin for acorn.
@types/estree	Estree type definitions (only types).
magic-string	In-place string rewriting used by the compiler and migrate codemod.
esrap	Estree → source code printer used at the end of the transform pipeline.
zimmerframe	Tree walker used by analyze and transform.
is-reference	Helper for distinguishing identifier reference vs. binding sites.
aria-query	Used by the a11y warnings under 2-analyze/visitors/.
axobject-query	Same purpose — accessibility role tables.
clsx	Class-list joining for attr / class: / spread props (matches React/Vue idiom).
devalue	Server-side serialisation for $state snapshots.
esm-env	DEV and BROWSER flags used by tree-shaking dev-only code.
locate-character	Maps offset → line/column in error messages.
@jridgewell/remapping	Source-map composition (preprocess pipeline).
@jridgewell/sourcemap-codec	Source-map encode/decode.
@types/trusted-types	Type definitions only.

Dev dependencies (packages/svelte)

15 in total. Notable:

Package	Purpose
rollup	Build tool (see packages/svelte/rollup.config.js).
@rollup/plugin-commonjs, @rollup/plugin-node-resolve, @rollup/plugin-terser, @rollup/plugin-virtual	Rollup plugins.
dts-buddy	Rolls up .d.ts files into packages/svelte/types/.
vitest	Test runner.
@playwright/test	Browser tests under tests/runtime-browser/.
esbuild	Used by some generation scripts.
tinyglobby	Cross-platform glob matching for build/test scripts.
@jridgewell/trace-mapping	Source-map debugging for tests.
source-map	Mozilla source-map library, used by some test helpers.
@types/aria-query, @types/node	Type definitions.

Dev dependencies (top-level package.json)

16 in total. Notable:

Package	Purpose
@changesets/cli	Versioning + release management.
@svitejs/changesets-changelog-github-compact	Compact GitHub-style changelog formatting.
@eslint/js, eslint, typescript-eslint	Lint stack.
@sveltejs/eslint-config	Project-specific eslint preset.
eslint-plugin-svelte	Lints .svelte files.
eslint-plugin-lube	Custom rules for the Svelte codebase.
prettier, prettier-plugin-svelte	Formatter.
@vitest/coverage-v8	Coverage runner.
playwright	Test browser automation.
jsdom	DOM emulator for non-browser tests.
v8-natives	Used by pnpm bench for deterministic JIT control.
vitest	Test runner (transitive — also under packages/svelte).
typescript	Type-checker.
@types/node, @types/picomatch	Type definitions.

Lockfile

Single pnpm-lock.yaml at the repo root, ~165 KB. The pnpm version is pinned to pnpm@10.4.0 via package.json#packageManager.

Bundle analysis

pnpm dlx knip (configured in packages/svelte/knip.json) detects unused exports. CI does not run this on every PR; it's a manual hygiene tool.

See also

• Tooling — how each of these is used in the build/test pipeline.
• Development workflow — when each tool runs.