From wikipedia:

"DuckDuckGo's results are a compilation of "over 400" sources, including Yahoo! Search BOSS, Wolfram Alpha, Bing, Yandex, its own Web crawler (the DuckDuckBot) and others. It also uses data from crowdsourced sites, including Wikipedia, to populate knowledge panel boxes to the right of the results."

https://en.wikipedia.org/wiki/DuckDuckGo

this brings back memories of metacrawler

They use this little known "algorithm" as their backend: https://www.bing.com/.

It's remarkable, BTW, that most people at the same time believe that Bing sucks, and DDG is "just as good as Google". For me that hasn't been my experience at all: Google is far, far ahead of Bing (and by extension DDG) in terms of relevance.

It seems possible without bias, DDG went full on with instant results. I guess Bing does those now too, I don't know, but the choice of scope and resources to use can be enough distinction to colour people's perceptions.

AFAIK they don't have their own algo, they are just a front end for other search engines (Bing etc.) depending on where/what you're looking for.

They have to have some (possibly trivial) algorithm for aggregating the sources they combine.

If they're doing that, sure. I'm not sure it's that sophisticated. Last I heard they sourced different engines for different types of things/geographies not necessarily mixing results from multiple sources for a single query. But this is all based on things I've read in passing rather than any serious research/insider knowledge.

I think DDG is mostly just a front-end on Bing, at least that's how they've been doing things in the past.

It's a nicer skin with better privacy around mainly this search engine: bing.com from Microsoft.