Decks release - captcha on course creation

This morning, we had the return of quite an aggressive spambot this time to Decks, creating tens of thousands of courses, which has previously caused site performance problems for the whole of Memrise.

We’ve just deployed the addition of a reCaptcha “I’m not a robot” button on the course creation page.

Hopefully it works well and isn’t too intrusive.

We had already done the work of reviewing lots of options for captchas, and this was by far the one with the best user experience, and which was the easiest to implement. Also we’re confident Google will update it as attackers alter their behaviour.

Apparently it won’t work in mainland China, because the whole reCaptcha service is blocked. If this is a large problem for Decks users, we can revisit it, but felt it was more important to keep the site up and working for most users in the short term.

Please let us know if you have any problems!


I’m a user in China and I would like my students to be able to create their own courses. Is there no other way than reCaptcha?

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Do you mean, is reChaptcha blocked in China?

Yes, unfortunately reCaptcha is blocked in China.

There’s currently no other way to create a course there.

If there’s enough demand, we could implement a China-specific captcha for those cases. Do you happen to know what would be the best one to use?

We did quite a lot of research into captcha options. reCaptcha was much better in terms of user experience and ease of implementation than other options. It’s biggest flaw is that it doesn’t work in China.

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