The chat page loads quickly, but the answer takes too long to appear. It works over fixed broadband, then intermittently disconnects on mobile data. For an AI API proxy, access problems often surface only when a client calls the actual API.

Cloudflare, CDN07, CDNetworks, Alibaba Cloud ESA, and Gcore are all candidates for a service aimed at users in Mainland China. Compare them using the actual request origin, evening peak network performance, streaming responses, and attack protection. A Hong Kong edge location or a fast homepage test does not establish that a complete AI conversation will work reliably.

First, identify the device that actually calls the proxy API

“Our users are all in Mainland China” does not fully describe the network requirements of an AI API proxy service.

Some users make requests directly from a webpage. Others connect through a desktop client. Some customers integrate the API into their own systems, so the customer's server is what actually connects to the proxy service.

Each setup places different demands on the CDN.

Suppose your customer is in Shanghai but hosts their application on a server in Singapore. From the proxy API's perspective, the request comes from the Singapore data center. Choosing a provider solely from a Shanghai home broadband test could miss the actual request path.

Conversely, if a user in Mainland China calls the API directly from a phone, a low-latency test from an overseas cloud server cannot substitute for a real mobile network test.

There is another path to test separately: the connection from the proxy server to the upstream model service. A CDN in front of the proxy hostname usually handles the path from the caller to the proxy entry point. Upstream model queuing, connection failures, or slower generation must also be investigated with logs from the proxy server.

For a service with an origin in the United States and users in Mainland China, the distinction between dynamic API acceleration and cross-border origin connectivity can help you break down where time is spent. Then you can decide whether to invest in the CDN entry point, the origin location, or the upstream connection.

How should you compare these five providers?

The candidates below are grouped by product approach. You can narrow the actual trial to two or three providers so you do not change too many variables at once.

Cloudflare: Keep your current setup as a baseline

If your service already uses Cloudflare, its current configuration and operational records provide a useful baseline. They can show which part of the request path a new option actually improves.

Cloudflare offers DDoS protection against attacks on the proxied entry point. Its web application firewall (WAF) and rule configuration capabilities should be assessed against the specific plan. Managing domain proxying and security settings on one platform can also be convenient for the team.

When serving users in Mainland China, distinguish Cloudflare's global network from its China Network. Cloudflare's China Network documentation describes the China Network as a separate subscription for Enterprise customers and requires a valid ICP filing or license for the onboarded hostname.

Do not assume the delivery terms of the China Network are included when comparing standard international plans.

Before trying an alternative, keep the existing Cloudflare setup as a baseline. Use the same origin and API, run tests at similar times, and send requests from actual user networks. That will show whether the new option reduces connection failures, long waits, and interrupted streams.

If the current setup works most of the time and problems occur only on particular carriers or at certain hours, investigate those cases first. A complete migration may not be the most economical first step.

CDN07: Configure network paths and protection together for users in Mainland China

An AI API proxy with an overseas origin, most of its revenue from users in Mainland China, and recurring attacks may want to evaluate CDN07 early.

Our DDoS-protected CDN service offers configurable edge location distribution, application bandwidth, and security policies, along with technical support in Chinese. For an AI API proxy, the configuration discussion can start with the real workload: which provinces and carriers users are on, which API endpoint receives most calls, and how many connections remain open during a normal peak.

Projects requiring access through locations outside Mainland China can also assess our DDoS-protected CDN option without an ICP filing while considering the origin region and access requirements from Mainland China in the same integration plan.

This approach is relevant when the requirements are clear:

• Most users are in Mainland China, and evening API performance directly affects renewals.
• The origin is in Hong Kong, Japan, the United States, or another region, and the team wants to keep its current deployment.
• The API needs performance improvements as well as protection from DDoS attacks and high-frequency malicious requests.
• The team wants to discuss incidents in Chinese and adjust security policies to fit the workload.

Before integration, list the AI API's specific behaviors. Short chats, long-running generation, file uploads, and client-initiated calls cannot be represented by a homepage test. In particular, test Server-Sent Events (SSE), where the server continuously sends events to the client. Check whether content is forwarded promptly, whether idle periods trigger a timeout, and whether requests still complete with protection enabled.

Because edge locations and policies can be configured, the test plan should reflect the workload. Even with the same CDN brand, a Hong Kong origin and a U.S. origin should not be expected to deliver identical results.

CDNetworks: Evaluate dynamic delivery and security across multiple markets

If the AI API proxy serves Mainland China, Southeast Asia, and other international markets, CDNetworks is another candidate to consider.

Its Dynamic Web Acceleration product combines connection reuse, transport optimization, and dynamic content delivery. It is worth examining for API traffic that cannot be accelerated through a shared cache. Its Cloud Security portfolio also offers DDoS protection, a WAF, bot management, and API security.

Ask the provider to answer two questions in the proposal: what path dynamic requests take, and which protection services are enabled along that path. A quote for content delivery alone may not include the security configuration the AI API needs.

This type of service may suit a team with technical staff to manage integration across multiple origins or markets. Test customers in Mainland China and international markets as separate groups. Compare connection success and completed conversations for each before deciding whether the overall service fits.

If the project has no ICP filing, state that you need delivery from locations outside Mainland China. Ask the provider to specify the available regions, onboarding requirements, and pricing scope. Having network resources in Mainland China does not establish which resources an unfiled hostname can use.

Alibaba Cloud ESA: Compare overseas delivery and Mainland China access optimization within an existing Alibaba Cloud setup

Alibaba Cloud ESA combines acceleration, security, and edge computing in one product family. Teams already using Alibaba Cloud servers, monitoring, or account management can assess it within their existing operations.

For an overseas origin serving users in Mainland China, ask specifically about Mainland China access optimization and how it uses edge locations in Hong Kong and other regions, along with associated network resources, to improve cross-region access. The official documentation lists separate activation and billing requirements.

Confirm “selecting an overseas acceleration region” and “purchasing Mainland China access optimization” separately. Connecting to ESA does not mean every network optimization and security feature has been enabled on the account.

Alibaba Cloud's ESA onboarding limitations also distinguish acceleration regions. A hostname needs the applicable ICP filing when the selected region includes Mainland China. If your service has no filing, check the plan for regions outside Mainland China rather than assuming that an overseas origin makes every region available.

For an AI API proxy, include the DDoS protection tier, API rules, acceleration regions, and additional usage in the same quote. Whether Mainland China access optimization justifies its cost should be determined by actual API results.

Gcore: Assess delivery and API security for a mix of Mainland China and international customers

Gcore is a candidate for a global service, particularly if the team needs to assess content delivery and application security together.

Its WAAP product documentation describes combined web application and API protection, including a WAF, bot management, DDoS protection, and API security. For an AI API proxy, focus the comparison on API rules, false-positive handling, and how the security services work with CDN delivery.

For example, public documentation, login endpoints, and model API calls have very different traffic patterns. Applying the same bot decision to all three could disrupt legitimate clients. Ask the provider to demonstrate configurations using your API inventory, not just screenshots of the control panel.

Gcore's global network coverage alone cannot establish that a particular carrier in Mainland China will remain stable during evening peaks. If Mainland China is the primary market, use results from those networks to decide whether it advances to the next round. If international customers also represent a substantial share, keep those tests too, so an improvement for one group does not conceal a regression for another.

Make the evening trial more specific than “one request worked”

An AI conversation may involve connection setup, authentication, an upstream wait, continuous content delivery, and request completion. Users experience only whether it feels fast and whether it disconnects, but troubleshooting requires measurements for each stage.

Start with the regions that generate the most real usage, covering key carriers and request methods. Do not spend most of the trial measuring parts of the country where you have almost no customers merely to increase the location count.

Test when users actually call the API

One daytime test and one evening test can reveal a pattern. For a longer-term purchasing decision, repeat the measurements across multiple days.

If customers mostly use the service in the evening, collect complete records during the corresponding Beijing-time hours. Do not compare one provider's best daytime result with another's evening peak result.

At a minimum, record the following:

Receiving HTTP response headers does not mean the model has started answering. A streaming API may first send role metadata, a heartbeat, or an empty event. Record these separately from actual answer content.

To reduce noise from fluctuations in the upstream model, run two types of requests. Have a service you control return test data at a fixed pace to observe delivery, and call the real model to assess the user experience. The first makes faults easier to locate; the second shows whether users will accept the result.

An average latency calculated only from successful requests can hide frequent failures. Keep completion rates and failure records in the comparison report as well.

If a large block of text appears at once, check response forwarding

Some APIs are not consistently slow; they pause and then display a large block of text at once. When this happens, investigate the proxy application, reverse proxy, and how the frontend reads the response, as well as the network.

NGINX's documentation on response buffering explains how forwarding behaves with buffering enabled and disabled. For streaming APIs, proxy-layer buffering can change when data reaches the client. Disabling response caching alone does not show that every forwarding layer handles the response as a stream.

During testing, compare when the origin sends content with when the client receives it. If the origin itself sends in batches, changing CDNs may not help. If the origin sends continuously but the client receives data only after long gaps, inspect the intermediary proxies and client-side reading logic.

For connections that remain open, check idle timeouts and the maximum duration allowed for a single response. The integration requirements for long-lived connections and multi-tenant APIs offer a related checklist.

The webpage works but the API fails: Test the CORS preflight before buying

An AI API proxy with a web chat interface can show a puzzling result: a command-line call succeeds, but the webpage keeps reporting an error.

If the page and API use different origins, such as a page at app.example.com and the API at api.example.com, the browser performs cross-origin checks. A call with certain request headers may first send an OPTIONS preflight request.

MDN's CORS guide explains this mechanism. The browser asks whether the server permits the origin, method, and request headers before proceeding with the actual request. A preflight blocked by a security rule or missing required permission headers will prevent the subsequent call.

The following command runs on macOS, Linux, or Windows Subsystem for Linux (WSL). Replace the example addresses with your own webpage and API hostnames. It checks the preflight response without submitting a model-generation request:

curl -sS -i --connect-timeout 10 --max-time 20 \
  -X OPTIONS \
  -H 'Origin: https://app.example.com' \
  -H 'Access-Control-Request-Method: POST' \
  -H 'Access-Control-Request-Headers: authorization,content-type' \
  'https://api.example.com/v1/chat/completions'

Check the status code and these types of response headers. The following fields are examples for this request only:

Access-Control-Allow-Origin: https://app.example.com
Access-Control-Allow-Methods: POST
Access-Control-Allow-Headers: authorization,content-type

A preflight should generally return a successful status such as 200 or 204 and allow the required origin, method, and request headers. If it returns 403, a redirect, or an HTML verification page, inspect security logs and origin settings. The status code alone does not establish that the CDN caused the problem.

If the browser request includes credentials such as cookies, check the credential-related settings too. You cannot simply allow every origin with a wildcard in that case. The actual API response also needs the correct CORS headers.

curl displays the response but does not perform the browser's full CORS checks. After running the command, verify the behavior in the actual webpage.

This test also helps evaluate a provider: it shows whether they will tune the configuration around a real API. The API needs to accept programmatic requests, and its protections must work with that traffic. Requiring an SDK to solve a browser CAPTCHA, or disabling protection for the entire API hostname, is not a sustainable fix.

Price the service against real API usage

Request counts, data transfer, and connection occupancy do not necessarily grow at the same rate for an AI API proxy.

A short text response may transfer little data but keep a connection open for a long time. Image, audio, and file requests may generate substantial uploads and downstream traffic. Monthly transfer from the homepage alone will not predict the cost of the API integration.

When requesting quotes, send each candidate a concise workload profile:

• The main request regions and approximate share of browser, client app, and server-to-server calls.
• Daily request volume, peak load, and typical response duration.
• The share and size of text, image, and audio requests.
• The attacks encountered and the security capabilities you plan to enable.
• Any need for additional network optimization, log retention, or technical support.

Then check what the quote covers: application traffic, request volume, bandwidth, rule counts, logs, security services, and support. Ask which items are included in the plan. The breakdown of DDoS-protected CDN plans and additional usage can help you apply the cost categories to your own data.

If users repeatedly retry after disconnections, the CDN may handle more requests and traffic, while the upstream service may receive additional calls. Whether those calls are billed again depends on how the application and model service process them. Include the cost of failures in the comparison instead of looking only at the advertised monthly plan price.

After the trial, narrow the shortlist using three criteria:

• Customers on your main networks can complete requests reliably.
• Webpages, SDKs, and streaming APIs still work after the required protections are enabled.
• Peak usage and the cost of additional services fit the budget.

If most users are in Mainland China and the origin is overseas, you can contact CDN07 about integration to share the origin region, user distribution, and API types. Those details provide a basis for discussing edge locations, bandwidth, and security settings. Sharing a concrete workload will yield a more useful proposal than asking only about mitigation capacity and monthly price.

What else should you ask before buying?

If AI responses cannot be cached, is a CDN still useful?

Yes, but assess the value of dynamic delivery and protection. User-specific conversations should not be placed in a shared cache to raise the cache hit ratio. Network path selection, connection handling, and entry-point protection may still improve the service. Measure the effect under comparable workload conditions.

Is a Hong Kong DDoS-protected CDN always faster than other locations?

No. Edge location is only one factor. The paths from users to the edge and from the edge to the origin, along with congestion and routing, also matter. Hong Kong is worth including in Mainland China access tests, but base the purchase on real API results during evening peaks.

Does WebSocket support guarantee that AI streaming works?

No. WebSocket and SSE are different protocols. A claim of “long-lived connection support” also does not specify buffering, idle timeout, or maximum response duration. Test the protocol your application actually uses.

Could legitimate users sharing one IP address be blocked by mistake?

Yes. Corporate networks, mobile networks, and customer backends can put multiple users behind one public egress IP. Account identity, API permissions, and application quotas should inform the rules. Requests from the same IP do not necessarily belong to the same user.

With a limited budget, which two providers should you try first?

If you already use Cloudflare, keep the current setup and compare it with one option that matches your main customer regions and operational needs. For a concentrated Mainland China user base, overseas integration needs, and technical support in Chinese, consider testing CDN07 first. If you already use Alibaba Cloud, assess the relevant ESA plan. For customers across several international markets, compare specific CDNetworks or Gcore proposals.

A smaller trial makes differences easier to see. The purchasing decision should turn on whether customers can complete requests and whether your team can locate and resolve problems promptly.