Wunderlist, the to-do app based out of Berlin, is now approaching 13 million free and paid accounts. And today it is adding a new feature that it hopes will make the app a lot more useful and more used: it’s finally turning on an API so that people can create or modify Wunderlist tasks in other apps, and get alerts for Wunderlist tasks when they’re in those apps.
The first wave of API partners — which have been playing around with a closed beta of the API since January, the company tells me — are Sunrise, Slack, OneNote, HipChat, Zapier and Scanbot.
Wunderlist announced the API was about to be released in March of this year, but in fact it is a long time in coming. I’d actually heard of API plans back in 2013, when the company raised $19 million led by Sequoia (significant for being the storied VC’s first investment in a Berlin startup). At the time, I was told the API would be coming “soon.”
As it happened, the team had to rebuild its whole product to get the API to where they wanted it to be (I’d love to get a look at that years-long to-do list). That happened finally with the launch of Wunderlist 3 in July 2014.

In fact, two sources have gone one step further and named Microsoft as potentially a very strong contender. (Interesting when you consider that two of the early API partners here are Microsoft’s Sunrise and OneNote.)
“Nothing to share on this topic,” a Wunderlist spokesperson says in response to my questions about M&A activity.
Whether or not Wunderlist is getting acquired, adding in functionality such as an API is an important way of differentiating it from the sea of other to-do apps.
And we really do mean a sea. By Zapier’s count, there are at least 40 credible to-do apps out there worth noting. Wunderlist describes itself as “outperforming” in its category at the moment in terms of growth, although Any.do, another to-do app, is not far behind with 12 million users of its own app, and another 4 million of its lightweight Cal app.
Next up, Wunderlist tells me, will be an integration center — which sounds not unlike a similar feature you would get in a product like Slack giving users a very easy way of linking in whatever apps they choose to have feeding into Wunderlist. (Note that Wunderlist already has made a little bit of an inroad into integrations, too: in October, Dropbox became its first integration partner.)
Both the API and future integration center will be free for all Wunderlist users, although there are potential plans to monetise, too. Specifially, the startup is looking to put a ringfence around certain more business-focused integrations that could be sold along with its Pro and Business tiers, which start at $4.99/month for Pro and in a sliding scale of pricing based on the size of the business in question.
