It’s not a perfect replacement, but searching OpenStreetMap via https://overpass-turbo.eu/ with a query like
[out:json][timeout:25];
(
nwr["diet:vegan"~"yes|only"]({{bbox}});
nwr["cuisine"~"vegan"]({{bbox}});
);
out geom;
can be useful and is often more up-to-date with respect to restaurants that actually still exist.
An example: https://overpass-turbo.eu/s/2shI
My post may well be tainted by my growing frustration with HappyCow growing increasingly out of date in my region. I frequently find restaurants listed that have long since closed and new restaurants not listed at all. But criticism in my workaround and its deficiencies has been wholeheartedly acknowledged and appreciated.
Though HappyCow is closed-source and proprietary, it’s like OSM in that it relies on user reports. Have you submitted new restaurants and reported closed ones?
Happycow always had editor/staff issues, they frequently introduced mistakes, and modified copy to make it worse, not better.
These days happycow tends to either not act on submissions, or they take a ridiculously long time to act, even for submissions of completely vegan eateries. (The suggested priority).
Happycow also accepts money to promote non-vegan establishments first, and even increases their search radius to the point where you can be sitting in a vegan eatery 10 suburbs away from a fish and chip shop, that doesn’t even meet the listing criteria, but will appear at the top of your search because they paid.
I used to be a contributor, had over 1,000 submissions/additions, and many more updates. Dealing with Eric and his staff was a constant nightmare, and the site just kept getting worse and worse in every respect, including promoting items as vegan, that the Vegan Society, peta, and every legitimate vegan body globally state are not vegan.
My partner was an ambassador, she removed herself from that role a year, or so ago, and now rarely interacts with the site due to its growing issues, errors, and uselessness.
Something like happycow can only work via user effort, as is the case with wikis. Most people are unwilling to put that effort in, they expect to be spoon fed, but happycow is more likely to hit you with the spoon, so why would anyone bother?