The service provides an "anniversary calculator" that suggests reasons to celebrate wedding or relationship anniversaries and birthdays. Input must specify a start date and the event type, either birthday or anniversary (the default). The service returns a suggestion for a reason to celebrate based on the time elapsed since the start date.
API methods generate text suggestions based on the number of days, weeks, fortnights (2-week periods), months or years since the specified start date. Optional annotations explain potentially obscure references in the suggestions.