Browser environment check

Am I Flagged as a China User by Claude? Check Your Browser Signals

Check whether timezone, language, fonts, and other browser-visible clues resemble a mainland China environment.

This is not an account conclusion from any platform; it only explains signals exposed by this browser.

Processed in your browser
No result upload
No sign-in required

Live auditLOCAL

—Not checked yet

Environment signal score

The score is an estimate from public browser clues, not a statement of how any service will decide.

About 2 seconds · No location permission

See what the score looks like

These are sample results, not your score. Start the check on the right to generate a local result.

High sample

72/100

Several mainland-like clues matched together

Low sample

12/100

Fewer visible clues — a cleaner local profile

Samples explain the scale only. They never read an account.

Privacy boundary

Before you begin

The score is an estimate from public browser clues, not a statement of how any service will decide.

The check runs locally and does not upload detector signals or results. Google Analytics receives standard visit data such as IP address, browser, device, language, and page information.

This tool does not read accounts, sign-in state, history, or private page content.

The result lives only in this page's memory and disappears when you refresh or close it.

Nine public signals

What Claude Checks — Am I Flagged as a China User by Claude?

How browser signals relate to China-user concerns

Each item shows its maximum weight, current state, and a short explanation of the evidence used. Detection details · FAQ

System timezone

stronger

Reads the IANA timezone reported by the browser, such as Asia/Shanghai.

26Weight

Browser languages

stronger

Checks preferred language and language lists for Simplified Chinese regional preferences.

20Weight

Common Chinese fonts

moderate

Compares canvas text widths for differences left by common Chinese fonts.

16Weight

Vendor Chinese fonts

moderate

Looks for Chinese font families often bundled with devices or software.

10Weight

Browser or WebView

moderate

Looks for browser or embedded-container clues in publicly exposed identifiers.

8Weight

Device brand

weaker

Uses public device hints when available, with conservative user-agent text as a fallback.

6Weight

Intl locale

moderate

Reads the regional language settings resolved by internationalization APIs.

6Weight

UTC+8 offset

weaker

Checks whether the current date has an east-eight UTC offset.

4Weight

System and emoji proxy

weaker

Conservatively infers operating-system traits; this is weak evidence only.

4Weight

Claude

Am I Flagged as a China User by Claude? Search notes

If you are searching for “Claude 中国用户检测” or “你是 Claude 中国用户吗”, this page only explains timezone, language, font, and browser signals on this device. It never uses an IP address.

It cannot confirm “Claude 中国用户标记” or “Claude 封号中国”. People searching "am i flagged as china user claude" get the same honest answer: the score is not an account label or a decision by any platform.

Command-line check

Use it from curl

The separate API uses the network country/region code provided by Cloudflare/Vercel and Accept-Language to return a text or JSON report. It does not affect the local 100-point browser score.

The request may pass through Cloudflare before Vercel. The endpoint prefers CF-IPCountry, falls back to Vercel's country code, does not return a raw IP, and disables response caching.

# Text report — follows Accept-Language
$ curl https://amichinaflagged.com/api/check

# Force a Chinese response
$ curl -H "Accept-Language: zh" https://amichinaflagged.com/api/check

# JSON output
$ curl https://amichinaflagged.com/api/check?format=json

Transparent method

How It Works — Am I Flagged as a China User by Claude?

Nine signals total at most 100 points. Timezone and language are usually steadier; font, device, and system proxies deserve more caution.

How Claude Detects China Users — what this page can show

If you are wondering "am I flagged as a China user by Claude?", the practical starting point is the set of browser-visible signals a webpage can read—not an account record this site can access.

People search for Claude China-user detection because timezone, language, fonts, and browser identifiers can make an environment resemble a mainland China setup. SignalCheck Local runs the same category of checks in your browser: timezone up to 26 points, languages 20, common Chinese fonts 16, and smaller weights for vendor fonts, browser or WebView clues, device hints, locale, UTC+8 offset, and weak system proxies.

This is not Anthropic's official model, and it does not claim Claude uses these exact rules. It answers a narrow question: how strongly do the clues exposed by this browser resemble a mainland China environment profile? The local 100-point score does not use an IP address and cannot read Claude account status.

So when the query is effectively am I flagged as a China user by Claude, use the matched signals, weights, and unavailable items as an explanation of local evidence. Pair that with the FAQ and detection-details pages, and treat the number as an estimate—never as a platform decision.

How Claude Uses These Signals

If you're wondering "am I flagged as a China user by Claude?", here's what happens under the hood. Starting from Claude Code v2.1.196, Anthropic introduced region detection that checks browser-visible signals including timezone, language preferences, installed fonts, and proxy configurations. When enough signals point to mainland China, Claude may apply usage restrictions or account flags.

This tool replicates that detection locally — every check runs in your browser, and no scan data is ever uploaded. It explains environment clues, not account outcomes.

What a browser can and cannot see

It can read timezone, languages, selected internationalization values, and public browser identifiers that the browser exposes to webpages.
It cannot learn your physical location unless you separately grant location permission.
It cannot determine network routing, account status, or another service's internal rules.

Reading the score

The score reflects accumulated clues, not identity, nationality, or access eligibility. Read individual findings before relying on the total.

Low0–30

Medium31–60

High61–100

Managing your browser environment

If you test products across regions or care about privacy, these neutral habits can help:

Review browser language, timezone, and autofill settings regularly.
Use separate browser profiles for work, testing, and personal activity.
Install extensions you trust and understand what page content they can access.
End sessions on shared devices and keep your browser and system current.

These suggestions support privacy and environment management; they do not change rules a website applies for itself.

FAQ

Frequently asked questions

01Is this score accurate?

It is a transparent estimate from browser-visible clues. Device, browser version, and privacy settings can change the outcome, so it should not be treated as a certain conclusion.

02What information leaves my device?

The local browser check does not upload signals, scores, or results. Only an explicit /api/check request lets Cloudflare/Vercel process a network country code and Accept-Language; the API does not return a raw IP. When enabled, Google Analytics receives standard visit data, but custom events contain no scan results.

03Why check fonts?

Installed fonts can sometimes reflect device language or software origin. Font checking does not read files; it compares widths when the browser draws text.

04Why are some items unavailable?

Some browsers limit canvas, user-agent hints, or other APIs. When a reliable check is not possible, the item is unavailable and earns zero points.

05What does a high score mean?

A high score means several public clues agree. It does not confirm your location, identity, or the state of any account.