Second Circuit Holds Hague Service Convention Prohibits Email Service on Chinese Defendants

On December 18, 2025, just as TLB was going on holiday break, the Second Circuit issued its decision in Smart Study Co. v. Shenzhenshixindajixieyouxiangongsi, holding that the Hague Service Convention prohibits email service on Chinese defendants. As friend-of-TLB Ted Folkman wrote shortly thereafter, “This is the one we’ve been waiting for.”

The question of email service under the Hague Convention has long divided district courts but evaded appellate review. In 2024, the Third Circuit held that the Hague Convention prohibits service by email, but it chose not to publish its opinion, making it non-precedential. Smart Study is the first published decision on this question by a U.S. Court of Appeals.

Of Baby Sharks and Default Judgments

Smart Study is a Korean company specializing in children’s programming. It created the memorable song “Baby Shark” in 2019. In 2021, Smart Study filed a sealed complaint in the Southern District of New York alleging that 58 Chinese companies were selling counterfeit Baby Shark products in the United States. Without the benefit of briefing from the other side (which is typical in such intellectual property cases), Judge Gregory Woods ordered service by email under Federal Rule of Civil Procedure 4(f)(3).

When none of the defendants appeared, Judge Woods entered a preliminary injunction at Smart Study’s request. Two months later, however, two defendants moved to dissolve the injunction, arguing that the Hague Convention prohibits email service. Smart Study voluntarily dismissed these two defendants, but the judge was now alert to the issue. He ordered further briefing and ultimately denied Smart Study’s motion for default judgment against the remaining defendants. Smart Study appealed, but the Second Circuit dismissed for lack of appellate jurisdiction. (Disclosure: Maggie Gardner and I filed an amicus brief in support of Judge Woods’s opinion.)

Smart Study renewed its motion for default judgment. Judge Woods granted the motion with respect to 49 defendants whose physical addresses were unknown, because the Convention does not apply when that is the case. But he denied default judgment against two other defendants whose physical addresses were known because they had not been properly served. Smart Study appealed.

The Second Circuit’s Opinion

Writing for the panel, Judge Richard Sullivan began by describing the Hague Service Convention, Rule 4(f), and how they interact. The Convention requires each state-party to establish a central authority to execute requests for service received by other countries. The Convention also provides alternatives to service through the central authority. Article 8 permits service through diplomatic and consular agents. Article 10 permits service through postal channels, judicial officers, or other competent persons if the receiving state does not object. Article 11 allows states to enter bilateral agreements authorizing other methods of service. “And Article 19 clarifies that the Convention does not preempt a receiving state’s internal laws if they are more permissive.” Finally, Article 15 allows a court to enter default judgment if the document was transmitted by one of the means provided in the Convention, at least six months have elapsed, and no certificate of service has been returned.

Rule 4(f) governs service outside the United States and “often overlaps” with the Convention. Rule 4(f)(1) authorizes service by “any internationally agreed means” including the Hague Service Convention. Rule 4(f)(2) authorizes service by other specified means “if there is no internationally agreed means, or if an international agreement allows but does not specify other means.” And Rule 4(f)(3) allows the court to order other means of service “not prohibited by international agreement.”

Postal Channels

“Drafted in 1965,” Judge Sullivan observed, “the Convention unsurprisingly makes no mention of email service.” But Article 10(a) does allow service through “postal channels” if the receiving state has not objected. Courts are divided on whether “postal channels” covers email. (The U.S. government says that it does.) But in this case, the answer to this interpretive question makes no difference in the outcome because China has objected to service through postal channels, as Article 10 permits it to do.

Exclusive Means

Citing an excellent article by Maggie Gardner, Judge Sullivan concluded that the Convention creates “a closed universe” of means for service. He found support for this conclusion in the preamble’s stated objective to “create appropriate means” of service, inferring that means not created by the Convention are not appropriate, as well as the Convention’s repeated use of the word “shall.” Judge Sullivan also found support in the Convention’s structure. “[R]eading into the Convention’s silence implicit permission for all types of service not affirmatively barred,” he reasoned, “would render meaningless its approved methods of service, encouraging end-runs around the very system it created” (quotation marks omitted). And Articles 11 and 19, which allow states to mutually agree on other means of service and to unilaterally permit other means in their domestic laws, “would be superfluous if the Convention allowed serving parties to use unspecified methods of service beyond those already identified in the text.”

Other Arguments

The court went on to reject Smart Study’s argument for an “emergency exception” to Rule 4(f)(3), This rule “states only that a party may serve a defendant ‘by … means not prohibited by international agreement,’” Judge Sullivan noted, and “makes no mention of urgency or exigent circumstances.”

The court also rejected the argument that email service was proper under Rule 4(f)(2)(A), which allows service “as prescribed by the foreign country’s law for service in that country in an action in its courts of general jurisdiction.” Judge Sullivan correctly noted that Rule 4(f)(2) applies only “if there is no internationally agreed means, or if an international agreement allows but does not specify other means,” and here “the ‘internationally agreed means’—the Convention—prohibits email service in China.”

Default Judgment

Finally, the court held that Article 15’s provision allowing a judge to “order, in case of urgency, any provisional or protective measures” did not authorize the entry of default judgment without service. Judge Sullivan found it hard to see “how the entry of a default judgment qualifies as a ‘provisional or protective measure[ ],’” or how a default judgment would be proper “where the district court otherwise lacks personal jurisdiction.”

The opinion concludes by acknowledging the difficulties that intellectual property owners face in policing trademark and copyright infringement abroad. “But,” the court continued, “the Hague Service Convention was not designed to ensure that the service of process in China is as efficient and fast as domestic service in the United States under the Federal Rules of Civil Procedure.”

Conclusion

Judge Sullivan’s opinion in Smart Study is the first published Court of Appeals opinion addressing email service under the Hague Service Convention, but it is unlikely to be the last. The same question will soon be argued to the Seventh Circuit in Kangol LLC v. Hangzhou Chuanyue Silk Import & Export Co. (Disclosure: Maggie Gardner and I filed an amicus briefarguing that email service was impermissible, with Ted Folkman as our counsel.)

I applaud the opinion not just because I agree with the outcome but because it carefully addresses each of the issues raised. There is more that could be said in support of the Convention’s exclusivity: that its listed means of service are exclusive is supported not just by the Convention’s text and structure but also by the negotiating history, the unanimous views of the contracting states during three Special Commissions, the views of the Permanent Bureau of the Hague Conference on Private International Law, and the views of the U.S. executive branch. (For more on these sources, see the amicus brief in Kangol or our article in Judicature.)

It is also worth noting the many instances in which service by email may be permissible. First, the Convention does not apply—and so does not prohibit email service—when the defendant is located in a country that is not party to the Hague Service Convention. Second, even when the defendant is located in a state-party, the Convention does not apply when the defendant’s physical address is unknown. Third, the Convention does not apply when the defendant is served in the United States, for example through substituted service on a subsidiary or through service on U.S. counsel. And finally, if one interprets “postal channels” to cover email, email service is permitted in countries that have joined the Convention and have not objected to the use of such channels.

In this case, however, China has joined the Convention, the two defendants’ physical addresses were known, the defendants could not be served in the United States, and China has objected to the use of postal channels. Under these circumstances, the Second Circuit was right to hold that service by email is impermissible.