The best alternatives to Zammad are Zendesk, Intercom, and Opensource Builders. If these 3 options don't work for you, we've listed a few more alternatives below.
Zendesk is a service-first CRM company that builds software designed to improve customer relationships. As employees, we encourage each other to grow and innovate. As a company, we roll up our sleeves to plant roots in the communities we call home.
Suppdesk - a tickets manager with an easy workflow. A multi language helpdesk that can be used by support teams that want to open a channel of communication with its clients and have all this data in a place