They say they worked at Uber and small startups, they mention a ton of alternatives to their product, but never once mentioned Azure KV. And your comment is also the only comment mentioning it. Im not sure what Hacker News has against Microsoft and the Azure offerings, but AKV is one of the best secret managers on the market today. It does 90% of the features Doppler advertises, and the developer experience is awesome, even the deployment experience is great, especially when hosting in App Services (not required!).