Glossary

Great Firewall (GFW)

Definition

The Great Firewall is the colloquial term for China's filtering of many global internet services. Requests to filtered services are not answered. It is one of three compounding causes that make websites slow or broken for mainland visitors — alongside congested cross-border transit and DNS resolution outside the country.

What the Great Firewall is

The reason whole categories of third-party endpoints fail from mainland sessions. Google Maps, YouTube, Vimeo embeds, global font hosts, icon libraries, tag-manager endpoints, and auth or payment APIs can all fail behind the firewall.
One of three stacked causes. Cross-border transit congestion slows everything. Overseas DNS adds lookup round trips. The firewall blocks specific services entirely. Together they compound into the 15–30+ second loads and broken features that China visitors report.
A dependency-level problem, not a whole-site problem. A page that waits on filtered endpoints stalls until the browser gives up. A render-blocking script in the <head> stalls the whole page; an async embed leaves a hole where the feature should be.
Two failure classes help you diagnose. If everything loads late, the problem is transit or DNS — the requests reach the server but the path is slow. If specific parts are missing while the rest renders — a gray map, a dead video player, missing fonts — the problem is blocked dependencies.

What it is not

Not the cause of everything slow. General slowness comes from congested transit and overseas DNS — two separate failure classes. The firewall explains why specific features break, not why every asset takes 15 seconds to arrive.
Not proof your whole site is blocked. Your site is not blocked — specific third-party APIs are. The browser network tab from a mainland session shows which domains time out. The rest of the page may load fine around the gap.
Not a problem a VPN fixes for visitors. A VPN shifts the burden onto every individual user. It is not a fix for the people you are trying to reach.

Why the Great Firewall matters for foreign companies

It drives the dependency audit. The first step is identifying which scripts and APIs fail behind the firewall. Then each one gets a replace-or-proxy decision: Amap or Baidu Maps in place of Google Maps, domestic video hosts in place of YouTube embeds, WeChat Pay in place of global checkout calls, and self-hosted font files in place of global font CDNs.

It makes VPNs a non-fix for your audience. You cannot require every China visitor to run a VPN. The fix runs on your infrastructure, not on their device. And a VPN is not the only non-fix: offshore CDNs and image compression leave the cross-border path untouched. Shaving 200 KB off a page does not change a multi-second transit path.

It shapes the China-path architecture. Most brands keep their global website and add a China-facing edge layer with localized pages and replaced APIs. The hybrid architecture links your global CMS or API to a China-facing edge layer — content is authored once and delivered through two paths. The China path goes live while the broader China plan (entity, filing, full deployment) progresses in parallel.

Common misconceptions

"My site is blocked." Usually a dependency, not the site itself. Verify via the browser network tab from a mainland session — specific domains time out while the rest of the page loads.

"A VPN fixes it for customers." A VPN is not a fix for visitors. It shifts the burden onto every individual user and does not address the underlying infrastructure problem.

Frequently asked questions

What is the Great Firewall?

What services does the Great Firewall block?

Google Maps, YouTube, Vimeo embeds, global font hosts, icon libraries, tag-manager endpoints, and auth or payment APIs can all fail behind the firewall. The problem is dependency-level, not whole-site. A page that waits on filtered endpoints stalls until the browser gives up.

Is my entire website blocked in China?

Usually not. Your site is not blocked — specific third-party APIs are. The browser network tab from a mainland session shows which domains time out. The rest of the page may load fine around the gap.

Will a VPN fix the Great Firewall for my customers?

No. A VPN shifts the burden onto every individual user. It is not a fix for the people you are trying to reach. The fix runs on your infrastructure, not on their device.

How do I make my website work in China despite the Great Firewall?

The first step is identifying which scripts and APIs fail behind the firewall. Then each one gets a replace-or-proxy decision: Amap or Baidu Maps in place of Google Maps, domestic video hosts in place of YouTube embeds, WeChat Pay in place of global checkout calls, and self-hosted font files in place of global font CDNs. Most brands keep their global website and add a China-facing edge layer with localized pages and replaced APIs.

Related terms

CN2 / CMI Transit — CN2 and CMI are names for carrier networks and transit paths within China's telecommunications infrastructure.
CDN (China Content Delivery Network) — a mainland CDN means edge caching on China networks to cut cross-border latency — the edge has to be inside the country for a CDN to touch the cross-border hop.
MIIT (Ministry of Industry and Information Technology) — the national ministry whose systems run mainland filing verification and licensing.
Bei'an (备案) — ICP Filing — the mandatory registration for most websites hosted on mainland servers. It registers the domain and its operator with the authorities, ties the site to a hosting provider and a legal operator, and must be completed before the site can stay online.