Stack Break Lab

Which parts of a foreign web stack break first in mainland China — measured, not guessed.

An open lab with tiny, single-dependency demo pages and reproducible network + browser checks from real mainland China infrastructure (Alibaba Cloud behind launchready.cn). Each run produces a machine-readable verdict — Blocked, Degraded, or Reachable — plus screenshots.

Maintained by Chinaready; evidence runs on launchready.cn mainland infrastructure.

• Live site: https://stackbreak.launchready.cn
• Latest results: https://stackbreak.launchready.cn/results/
• Beijing view: https://stackbreak.launchready.cn/demos/beijing-view.html
• Companion article: https://chinaready.co/insights/which-parts-of-your-stack-break-first/

What this is

Most teams treat "China access" as one big switch. It is not. A site that loads from London can fail in a dozen small, independent ways from Shanghai: a blank login button, a hero with no typeface, a checkout that silently stalls.

This lab isolates each failure. Every page under demos/ loads exactly one third-party integration the way a normal product would, then reports whether that dependency actually arrived.

Category	Demos	Services
Fonts and icons	3	Google Fonts, Material Symbols, Adobe Fonts (Typekit)
Auth and identity	3	Google reCAPTCHA, Auth0, Google Sign-In
Analytics and tags	2	Google Tag Manager, Google Analytics 4
Maps, media, embeds	3	YouTube, Google Maps, Vimeo

The Beijing view replays the latest mainland snapshot — same evidence for every visitor, regardless of location or VPN.

How evidence is collected

GitHub (this repo)  --push-->  self-hosted runner on launchready.cn (mainland China)
                                  |
                                  +-- probe/china-dependency-probe.sh  (curl + dig)
                                  +-- Playwright  (Chromium, network capture + screenshots)
                                  |
                                  +-- writes results/<date>/ and results/latest.json
                                  +-- serves demos + /results/ via Docker (nginx)

1. Network probe (curl + dig) — domain reachability and latency.
2. Browser checks (Playwright) — what a real user sees: failed requests, blank players, spinners that never resolve — with screenshots.

Every verdict is stamped with test date, cloud region, and host. Results change with carrier, region, and time; treat each run as a single-node snapshot, not a legal or compliance conclusion.

The evidence workflow runs weekly (Mondays 06:00 Asia/Shanghai) on a mainland self-hosted runner and refreshes:

• results/latest.json — 11 single-dependency probes + Playwright screenshots
• results/netlify-latest.json — when Netlify site variables are configured
• results/vercel-latest.json — when Vercel site variables are configured
• results/firebase-latest.json — when Firebase is configured on the host (see deploy/env.example)

You can also trigger a run manually from GitHub Actions → evidence → Run workflow.

Quick start (local)

Outside China most demos succeed — that is the point of comparison with the mainland runs.

git clone https://github.com/chinaready/launchready-stackbreak-lab.git
cd launchready-stackbreak-lab

docker compose up --build
# http://localhost:8080/demos/  and  http://localhost:8080/results/

npm install
npx playwright install --with-deps chromium
npm test

./probe/china-dependency-probe.sh   # verdicts only meaningful from China

Copy .env.example to .env for optional vendor test keys. Every value is optional for a local build.

Repository layout

demos/         one HTML page per dependency + hub + Beijing view
probe/         targets.json + china-dependency-probe.sh
firebase-demo/ Firebase stack probe kit
netlify-demo/  Netlify stack probe kit
vercel-demo/   Vercel stack probe kit
tests/         Playwright specs
results/       published evidence (latest.json + dated snapshots)
public/        /results/ viewer + shared assets
deploy/        host bootstrap + runner setup (maintainers)

Whole-stack deep dives

Two kits deploy and probe an entire managed backend from the same mainland node:

• firebase-demo/ — Auth, Firestore, Storage, Functions, FCM, Remote Config. Results: /results/firebase.html.
• netlify-demo/ — Hosting/CDN, Image CDN, Functions, Edge Functions, Forms, Identity, Blobs. Results: /results/netlify.html.
• vercel-demo/ — Hosting/CDN, Functions, Edge Middleware, Cron, Blob, KV. Results: /results/vercel.html.

Contributing

Open an issue first to propose a dependency; maintainers confirm scope before you open a PR. See CONTRIBUTING.md.

Community

• Code of Conduct
• Security policy — report vulnerabilities privately

License

Copyright 2026 Chinaready. Licensed under the Apache License, Version 2.0. See NOTICE for attribution. Demos load third-party services for diagnostic purposes only; all trademarks belong to their respective owners.