# divriots/jampack

Optimizes static websites for best user experience and best Core Web Vitals scores.

Repository: https://github.com/divriots/jampack
Canonical: https://ross.abutalabs.com/products/jampack
Homepage: https://jampack.divriots.com/
Language: TypeScript
License: MIT
License Family: permissive
Topics: jamstack, static-site, blog, node, static-site-building, static-site-generator
Last push: 2026-06-01T16:55:25+00:00

## Health v2 (maintenance only)
Score: 70/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 85, release rhythm 35, longevity 100
- inputs: {"age_days": 1444, "days_push": 93, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1696, forks 29 (observed 2026-08-28T04:05:23.925240+00:00)

## What it is
Jampack is a post-processing CLI tool that optimizes the output of static site generators for best user experience and Core Web Vitals scores. It generates responsive image sets, compresses images to modern formats, inlines critical CSS, and applies above-the-fold optimizations.

## Use cases
- optimize static site images for core web vitals
- generate responsive srcset images from a single source image
- compress jpg and png images to webp and avif in a static site build
- fix CLS by adding missing image width and height attributes
- inline critical CSS to avoid FOUC
- lazy-load below-the-fold images automatically
- optimize CDN-hosted images via srcset URL transforms
- post-process SSG build output like Hugo, Astro, or Vite

## When to choose
- You have a static site or Jamstack site and want to improve Lighthouse/Core Web Vitals scores
- You want responsive, compressed images without changing your SSG or templates
- You want critical CSS inlining and above-the-fold prioritization as a build step

## When to avoid
- You need a bundler or full web framework - jampack is explicitly neither
- Your site is server-rendered dynamically rather than static output
- You need runtime image optimization rather than build-time post-processing

## Facets
- artifact type: cli-tool
- maturity: active
- function: image-processing, developer-tools, build-tool, cli
- domain: web-development, frontend, performance, web-design
- platform: cli, cross-platform
- tags: core-web-vitals, jamstack, static-site-optimization, responsive-images, critical-css, post-processing, cls, lazy-loading, webp, avif, nodejs

## Member repositories
- divriots/jampack (main) score 70

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:23.925240+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 2026-08-30T03:37:53.625897+00:00, confidence not recorded.
  - readme: https://github.com/divriots/jampack (fetched 2026-08-28T04:05:23.925240+00:00, sha 931ed95d9d27)
  - homepage: https://jampack.divriots.com/ (fetched 2026-08-29T11:13:06.060872+00:00, sha 06dbd7ab4d14)
  - site_page: https://jampack.divriots.com/installation (fetched 2026-08-29T11:13:06.069942+00:00, sha 431e709b68ca)
  - site_page: https://jampack.divriots.com/features/optimize-images (fetched 2026-08-29T11:13:06.071532+00:00, sha 627b8c2784f2)
  - site_page: https://jampack.divriots.com/features/optimize-images-cdn (fetched 2026-08-29T11:13:06.073300+00:00, sha fa3c22c186c8)
  - site_page: https://jampack.divriots.com/features/optimize-images-external (fetched 2026-08-29T11:13:06.075154+00:00, sha aa2df545dfe9)
  - site_page: https://jampack.divriots.com/features/optimize-above-the-fold (fetched 2026-08-29T11:13:06.076940+00:00, sha f4081636b32b)
  - site_page: https://jampack.divriots.com/features/embed-small-images (fetched 2026-08-29T11:13:06.078596+00:00, sha 694b1bde2cfd)
  - site_page: https://jampack.divriots.com/features/images-max-width (fetched 2026-08-29T11:13:06.080447+00:00, sha c2a8439981ee)
  - site_page: https://jampack.divriots.com/features/inline-critical-css (fetched 2026-08-29T11:13:06.082101+00:00, sha 62e1d1b4c8fe)
- Data as of 2026-08-30T08:39:29.467469+00:00.