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This bug appears to be dead. It probably will never show up again. The fact that it lasted an entire week was already pretty unbelievable. WeChat, please don’t come after me—I only published this after the bug was gone.

If you still remember, when signs of this bug first appeared, KUKU posted about it right away. See:

If you were quick enough to react, maybe you also tried to take advantage of this bug.

Also, even without doing refunds, there was another interesting angle. KUKU previously cross-posted that method on another platform, but because the wording around foreign exchange was considered too sensitive, the account was directly banned by the platform moderators 🤣.

What happened

[Time] Roughly from late October to November 4.

This was a very interesting bug—you could even call it a miracle bug. In short, refunds were sent directly back to your WeChat balance, including purchases made with US (international) credit cards. Meanwhile, the rewards on the US cards still posted, and the process could be repeated.

Why was this clearly a bug?

  • If you paid with a US credit card, the refund could still come back as WeChat balance, including cards that earn bonus rewards on WeChat Pay purchases (such as the discontinued Chase Ink Plus earning 5x UR, Chase Ink Preferred earning 3x UR, and certain AMEX cards earning 4x MR through refer offers).
  • At the same time as the instant refund, WeChat also issued a fee-free withdrawal coupon of the same amount, saving the 0.1% cash-out fee and making the whole thing effectively zero-cost.
  • The original purchase had already triggered US credit card points or cash back.

How this could generate UR/MR points

First, here’s why this was such a wild bug.

Because with manual effort, it basically functioned like a UR/MR point-printing machine, and you could rack up a lot every day.

Quick process

  • Go buy something from a merchant and pay with a card that earns bonus UR or MR points
  • Request cancellation and a refund on the same day after placing the order
  • WeChat processes the refund instantly back to balance and gives you a free withdrawal coupon

There are limits when using foreign credit cards with WeChat Pay. Under normal circumstances, an eligible card can spend online up to 2000 RMB or 6000 RMB per day. WeChat allows each account to link three foreign credit cards. If you have at least three WeChat accounts under your name—I didn’t test beyond that—that means at least 9 foreign cards total. In other words, one WeChat account might be able to spend up to 6000 RMB or 18000 RMB per day, YMMV. You can do the UR/MR math yourself; it was getting close to the level of MS in the US.

Breaking through the 6000 RMB limit was relatively difficult. It required contacting WeChat multiple times and uploading statements that included WeChat Pay transaction records. Also, not every online merchant supports charges all the way up to 6000 RMB, though some unusually permissive merchants did.

The limit mainly applied to larger transactions. In theory, after hitting the large-transaction cap, smaller transactions might still continue to go through, YMMV.

The spending limit resets daily, so after midnight you could continue again. If you really had the stamina, calling this a UR/MR point-printing machine would not be an exaggeration.

Was this bug worth exploiting?

First, we do not recommend exploiting any unnecessary bug, especially when it involves domestic Chinese merchants.

This bug was also highly addictive—after doing one transaction, you’d want to do another.

Personally, I think the odds of seeing this kind of bug again are low. The fact that it survived for a week was already a miracle.

The author kept testing for a week after the bug died and never saw it again. It did not reappear even during the huge Singles’ Day shopping surge, so it is reasonable to believe WeChat discovered and fixed it.

More likely, this happened only because of temporary internal system adjustments within WeChat Pay. Similar “bugs” sometimes appear in the US as well, often during transitions involving payment inflow/outflow systems.

Summary

This bug was pretty intense. Doing too much of it was obviously not a good idea. A little dabbling may be fun; pushing too hard can blow up in your face. Most likely it will never appear again, and given the capability of Chinese IT teams, if WeChat sees this article, it certainly won’t let this bug come back.

Don’t get your account shut down just to farm UR/MR points. Keep your foreign credit cards that earn bonus rewards on WeChat in good standing, and use them for everyday necessary spending instead. You can still earn plenty of points over time—steady accumulation is the real long-term strategy in the points game.

Related articles

“Using US Credit Cards in China” article/news roundup:

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