Update - In response to Dev, I dont want account and even if account thing is there, keep it optional. I am using FF to avoid account things otherwise I would be using Chrome by Google. And consider promoting it by using keywords and hastags making this come up in searches. A better bookmark manager in-tab like Chrome has and management of terms, selecting by searching and multiple selections, and duplication, would be appreciated. I have tons of bookmarks and wanting an advanced bookmark manager that helps me check them somedays and see which one are worth keeping and arranging them in a systematic way. Add tab management thing like tab suspension thing that chrome and edge has inbuilt. Sharing some links of other bookmark manager for suggestions and ideas. (Unfortunately cannot share, just check some on chrome extensions store for more). You have very less users. Thanks.

In short, make this without account. Will be successful in long run. Account is hindrance. And make it free for first, then decide for money. It will help you develop first. And rather ask for donations. Nobody pays for bookmark manager.

Doesn't work without an account or google account. What is the need for an account to manage bookmarks in browser is out of question but dev can answer and for users, report it and avoid it.