China Bulk SMS Gateway Needed

I want to send overseas SMS messages in bulk to mobile phones in mainland China, with delivery rates, compliance, and throughput that can be scaled as needed.

The core use case involves Chinese-language content that often includes external links, so the character set and URL display must work perfectly.

Interface and technical requirements
• I prefer integrating with my system via SMPP, with a dedicated username, password, and delivery-receipt port.
• The sending numbers must support customizable SIDs, allowing each marketing campaign to use its own brand signature.
• I expect to start with a small daily testing volume and steadily increase it after successful validation; the route must offer elastic throughput and stable delivery rates.
• You must be familiar with the regulatory requirements of China’s three major telecom operators and be able to provide failure codes, delivery-rate statistics, and callable reporting APIs / delivery-receipt queues.
• Chinese-language communication is preferred to facilitate the rapid confirmation of technical details and troubleshooting.

Required features already identified
- Bulk sending
- Content monitoring and pre-screening
- Sending reports and logs

Please briefly address the following in your proposal:
1. Existing international route resources and reference delivery rates;
2. Technical implementation of customizable SIDs and any possible limitations;
3. Minimum order quantity, price range, and subsequent scaling capacity for launching the test;
4. Available integration documentation, SDKs, or sample code.

I hope to work with a partner who is familiar with SMS gateways, experienced in international route management, and able to communicate in Chinese, so that testing can begin quickly and volumes can be scaled up reliably.