Kayako might be a bit more popular than Plan.io. We know about 1 link to it since March 2021 and only 1 link to Plan.io. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
Plan.io — Project Management with Repository Hosting and more options. Free for 2 users with 10 customers and 500MB Storage. - Source: dev.to / almost 3 years ago
One we used at a previous place, Https://kayako.com/ Small company, I'm sure there was not much effort put in customizing it. No idea on pricing but wouldn't expect it to be on the high side. Source: about 2 years ago
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