KDP Backend Keyword Stuffer — 7 Slots × 50 Characters
Pack your candidate keywords into KDP's seven backend keyword slots (50-character limit each) in priority order — per-slot usage and remaining space at a glance, over-limit and unfitted words listed separately, one-click copy into the KDP form. Runs entirely in your browser; your list is never uploaded.
Paste your candidate list — earlier words claim the earlier slots.
Frequently asked questions
Why seven slots at 50 characters each?
Because that's the actual shape of the KDP publishing form: seven backend keyword fields, each capped at 50 characters. Most keyword tools hand you one long list and ignore the field limits; this stuffer packs your words into the real slots, showing per-slot usage and remaining space as you fill.
Does my keyword list leave my browser?
No. The stuffer runs entirely in your browser — your word list is never uploaded or stored. Close the tab and it's gone; copy each finished slot straight into the KDP form when you're done.
How does it decide which slot a word goes into?
You bring the priority: words are filled in order, slot 1 first, and any word that doesn't fit a slot's remaining space moves on to the next. Words that fit nowhere (or exceed 50 characters on their own) land in a separate "didn't fit" list, so nothing silently disappears from your plan.