whatisgithub

What is sapper?

sveltejs/sapper — explained in plain English

Analysis updated 2026-06-24

★ 6,938TypeScriptAudience · developerComplexity · 1/5LicenseSetup · hard

In one sentence

Sapper was a framework for building full web applications with Svelte, handling routing and server-side rendering. It is now deprecated, SvelteKit is its official replacement and what you should use instead.

Mindmap

mindmap
  root((Sapper))
    Status
      Officially deprecated
      Archived for reference
      Replaced by SvelteKit
    What it did
      Page routing
      Server-side rendering
      Static site generation
    Migration
      Use SvelteKit instead
      Reference for legacy apps
    Tech
      TypeScript
      Svelte
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Code map

Detail Auto

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filefunction / class

What do people build with it?

USE CASE 1

Read the archived repository to understand historical Sapper patterns if you are maintaining a legacy Sapper project.

USE CASE 2

Migrate an existing Sapper app to SvelteKit by using this repo as a reference for the original routing and structure conventions.

What is it built with?

TypeScriptSvelteJavaScript

How does it compare?

sveltejs/sappera-ghorbani/pocketpal-ainutlope/llamacoder
Stars6,9386,9416,932
LanguageTypeScriptTypeScriptTypeScript
Setup difficultyhardeasymoderate
Complexity1/52/53/5
Audiencedevelopergeneraldeveloper

Figures from each repo's GitHub metadata at analysis time.

How do you get it running?

Difficulty · hard Time to first run · 1day+

Deprecated, do not use for new projects, migrate to SvelteKit instead.

Open source under the MIT license, use freely for any purpose, including commercial, with no restrictions beyond keeping the copyright notice.

So what is it?

Sapper was a framework for building web applications using Svelte, a JavaScript tool for creating user interfaces. It handled the parts of a web project that go beyond a single page, like routing between pages, server-side rendering, and generating static sites. The project has been officially deprecated and is no longer actively developed. The README directs users to SvelteKit, Sapper's successor and the now-recommended way to build Svelte applications. SvelteKit covers the same ground as Sapper with a more complete and maintained foundation. The repository is archived and kept available for historical reference and for projects that were built on Sapper before the transition. No new features are being added. The README is brief, containing only the deprecation notice, a link to the successor project, and a note about financial support for the Svelte ecosystem via OpenCollective.

Copy-paste prompts

Prompt 1
I have an old Sapper project and need to migrate it to SvelteKit. List the main structural differences between Sapper and SvelteKit and what I need to change.
Prompt 2
Explain how Sapper's file-based routing worked compared to SvelteKit's current routing system, so I can update my existing routes.
Prompt 3
My Sapper app uses server-side rendering. Walk me through the equivalent SvelteKit setup so I can migrate without breaking anything.

Frequently asked questions

What is sapper?

Sapper was a framework for building full web applications with Svelte, handling routing and server-side rendering. It is now deprecated, SvelteKit is its official replacement and what you should use instead.

What language is sapper written in?

Mainly TypeScript. The stack also includes TypeScript, Svelte, JavaScript.

What license does sapper use?

Open source under the MIT license, use freely for any purpose, including commercial, with no restrictions beyond keeping the copyright notice.

How hard is sapper to set up?

Setup difficulty is rated hard, with roughly 1day+ to a first successful run.

Who is sapper for?

Mainly developer.

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