The functionality / display of the blog can be edited in the theme code so you might not need an app.
What do you mean by "show one blog category at a time"?
Or another way to approach it, what is your url and what functionality do you want to achieve?
Founder of
Speed Boostr (Shopify optimization experts, theme customization, custom app development).
Creator of
Shopify Analyzer (first performance analysis tool for Shopify sites, free for the Shopify community).
Creator of
Order Automator (auto tag orders and customers + auto fulfill orders + email notifications).
Creator of
Theme Scientist (A/B testing app) and
Tip Jar (add a tip button to your store).
