# zendesk/cross-storage

Cross domain local storage, with permissions

Repository: https://github.com/zendesk/cross-storage
Canonical: https://ross.abutalabs.com/products/cross-storage
Language: JavaScript
License: Apache-2.0
License Family: permissive
Last push: 2025-12-10T05:35:05+00:00

## Health v2 (maintenance only)
Score: 48/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 56, release rhythm 8, longevity 100
- inputs: {"age_days": 4395, "days_push": 266, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2219, forks 176 (observed 2026-08-28T04:06:27.406597+00:00)

## What it is
A JavaScript library enabling cross-domain local storage sharing with per-origin permissions. It uses a hub-and-client architecture with embedded iframes and postMessage, exposing a promise-based API.

## Use cases
- share localStorage across subdomains
- replace shared root-domain cookies with larger client-side storage
- let multiple browser tabs on different domains access one data store
- store session data client-side without bloating request headers
- control which domains can read or write shared storage

## When to choose
- you need to share client-side data across multiple domains or subdomains
- you want to avoid cookie size limits and header overhead
- you need fine-grained per-origin permissions on storage access

## When to avoid
- you only need same-origin storage (use localStorage directly)
- you need server-side shared state or strong data integrity guarantees
- your target browsers lack iframe postMessage support

## Facets
- artifact type: library
- maturity: maintenance
- function: caching, security, http-client
- domain: web-development, frontend, privacy
- platform: browser
- tags: localstorage, cross-domain, iframe, postmessage, promises, javascript

## Member repositories
- zendesk/cross-storage (main) score 48

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:27.406597+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 2026-08-30T02:45:53.383680+00:00, confidence not recorded.
  - readme: https://github.com/zendesk/cross-storage (fetched 2026-08-28T04:06:27.406597+00:00, sha 2eee19327b06)
  - registry_npm: https://registry.npmjs.org/cross-storage (fetched 2026-08-29T10:26:02.753224+00:00, sha 16c3bbeb61dd)
- Data as of 2026-08-30T08:39:29.467469+00:00.