Achieving strong email deliverability to Sina.com and Sina.cn in China presents unique challenges due to stringent government regulations, ISP-specific filters, and a preference for transactional over bulk email. Senders must adopt an extremely cautious and adaptive approach to overcome these hurdles. Key strategies involve significantly reducing sending volume and implementing dynamic throttling to navigate strict rate limits, alongside employing dedicated IP infrastructure, ideally located within China or APNIC ranges. Content must be meticulously crafted in Simplified Chinese, be mobile-first, and strictly avoid sensitive or politically charged topics. Moreover, maintaining an impeccably clean, permission-based email list, ensuring robust sender authentication, and continuously monitoring deliverability metrics are critical to building and preserving a positive sender reputation with these highly sensitive ISPs.
12 marketer opinions
Further insights into delivering emails to Sina.com and Sina.cn underscore that success hinges on a deep understanding of their stringent rate limits and the unique characteristics of China's email ecosystem. It's evident that the infrastructure prioritizes transactional communications over large-scale marketing, often better suited for local platforms like WeChat. Therefore, senders must apply extremely precise volume control, deploy localized sending infrastructure, and meticulously tailor content for the Chinese audience. Crucially, maintaining an impeccable sender reputation through strict adherence to consent, rigorous list hygiene, and continuous adaptive monitoring is essential to navigate Sina's highly sensitive filtering and throttling mechanisms.
Marketer view
Marketer from Email Geeks explains that delivering to China can be challenging, suggesting that sending on Chinese or APNIC range IPs might improve performance and that getting added to a whitelist may also be an option.
18 Mar 2025 - Email Geeks
Marketer view
Marketer from Email Geeks explains that Sina's deferral message typically means stopping sending from the current IP and reducing volume, suggesting throttling sends down to a low level, possibly less than 500 per hour.
11 Jan 2023 - Email Geeks
2 expert opinions
Improving email deliverability to challenging Chinese providers like Sina.com and Sina.cn requires continuous adaptation from senders, primarily due to the inherent lack of transparency from Chinese ISPs regarding their complex filtering criteria. Unlike fixed daily limits, these providers typically employ throttling mechanisms, meaning sending too quickly will lead to temporary rejections. Therefore, senders must prioritize a consistent, gradual sending pace, rigorous list hygiene, and proactive bounce rate management to build and sustain a positive sender reputation and avoid frequent blocking of sending domains and IP addresses.
Expert view
Expert from Word to the Wise shares that email deliverability to China, including major providers like Sina, presents significant challenges due to the lack of transparency from Chinese ISPs regarding their filtering criteria. To improve deliverability, senders must consistently adapt their sending habits, maintain extremely clean mailing lists, and actively manage bounce rates. Chinese ISPs frequently block emails based on the sending domain and IP address, which often results in poor deliverability even for legitimate communications.
10 Dec 2022 - Word to the Wise
Expert view
Expert from Word to the Wise explains that internet service providers (ISPs) typically utilize throttling mechanisms instead of strict daily sending rate limits. Sending a large volume of emails too quickly can lead to temporary rejections. To enhance deliverability and mitigate throttling, especially when dealing with challenging ISPs such as those in China, senders should adopt a consistent and more gradual sending pace. This approach helps to build and maintain a positive sender reputation with the ISPs.
7 Aug 2023 - Word to the Wise
5 technical articles
The complexity of email deliverability to Chinese providers such as Sina.com and Sina.cn is further amplified by their unique operational environments. Success hinges on a sender's ability to maintain an impeccable IP reputation, adhere strictly to content compliance, and implement highly adaptive sending strategies to navigate dynamic rate limits. It is crucial to employ dedicated IP infrastructure, tailor content meticulously for the Chinese audience, and prioritize strong sender authentication and rigorous list hygiene to withstand their stringent filtering mechanisms.
Technical article
Documentation from SendGrid explains that sending email to China, including providers like Sina.com, requires careful attention to content, IP reputation, and local regulations. They emphasize maintaining a clean list, avoiding spam trigger words, and ensuring proper sender authentication (SPF, DKIM). It's crucial to understand that content often undergoes more stringent filtering, and a higher bounce rate can impact reputation. They also advise against using link shorteners or common URL shorteners as they are often blocked.
31 Oct 2022 - SendGrid Blog
Technical article
Documentation from Mailgun highlights that email deliverability in China is challenging due to strict government regulations and ISP-specific filters. For providers like Sina.com, it's essential to use dedicated IPs, ensure all content is in Simplified Chinese, and avoid banned keywords. They advise on warming up IPs slowly, maintaining a low complaint rate, and specifically mentioning that images should be hosted on Chinese CDNs if possible to avoid loading issues. Handling rate limits involves monitoring bounce codes and adjusting sending speed accordingly.
20 Apr 2022 - Mailgun Blog
How can I improve my email deliverability?
How can I improve my email reputation and deliverability?
How to handle email sending rate and connection limits from mailbox providers?
How to resolve QQ.com IP block issues and improve email delivery?
What are the best practices for email deliverability to QQ.com?
What are the specific rules and guidelines to deliver emails to the Chinese market?