# GoogleChromeLabs/application-shell

Service Worker Application Shell Architecture

Repository: https://github.com/GoogleChromeLabs/application-shell
Canonical: https://ross.abutalabs.com/products/application-shell
Homepage: https://app-shell.appspot.com/
Language: JavaScript
License: Apache-2.0
License Family: permissive
Archived: true
Last push: 2018-03-23T21:03:26+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 3984, "days_push": 3085, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: archived
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1168, forks 141 (observed 2026-08-28T04:03:50.818269+00:00)

## What it is
A demo and reference implementation of the Application Shell architecture, using Service Workers to offline-cache an app's UI shell and populate content via JavaScript. It serves as an educational example of progressive web app instant-loading patterns, with graceful degradation to server-side rendering.

## Use cases
- learn how to implement an application shell with service workers
- cache app shell for offline-first progressive web apps
- achieve sub-second first paint on repeat visits
- gracefully degrade to server-side rendering when service workers are unsupported
- reference architecture for instant-loading web apps

## When to choose
- you want a working example of the app shell pattern for PWAs
- you need to understand service worker caching strategies for UI shells
- you are teaching or learning progressive web app performance techniques

## When to avoid
- you need a maintained production framework - the project is unmaintained since 2018
- you need broad browser support including iOS service workers
- you want a turnkey PWA solution rather than a reference demo

## Facets
- artifact type: learning-resource
- maturity: abandoned
- function: caching, ssr, web-framework
- domain: web-development, frontend, performance
- platform: browser
- tags: service-worker, progressive-web-app, app-shell, offline-first, demo, architecture-example, web-server, nodejs

## Member repositories
- GoogleChromeLabs/application-shell (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:50.818269+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:28:45.400332+00:00, confidence not recorded.
  - readme: https://github.com/GoogleChromeLabs/application-shell (fetched 2026-08-28T04:03:50.818269+00:00, sha 190ef4be1f7d)
- Data as of 2026-08-30T08:39:29.467469+00:00.