Bulk Tab URL Opener by DalBan

Bulk Tab URL Opener lets you paste a big list of URLs and open them all without overwhelming Firefox.

Instead of firing open every tab at once, it keeps a limited number loading at a time (you choose how many). As each one finishes and you close it, the next URL in your queue opens automatically — the load count stays capped until the whole list is done.

Features

Paste one URL per line, or a block of text — it pulls out anything link-shaped and adds https:// if you left it off
Set the max number of tabs loading at once (1–50)
Adjustable delay between tab creations, so Firefox isn't hit with a burst all at once
Optional: remove duplicate URLs, sort alphabetically, or run the whole batch in a new window
Quick popup for short lists, or an "Open full page" view with more room for big batches and a live progress view
Dark mode by default, with a one-click switch to light mode
Settings are remembered between sessions

Privacy
Nothing here talks to a server. No analytics, no telemetry, no remote code. The only network requests are the pages you asked to open — same as if you'd typed each URL into the address bar yourself.

Permissions

tabs — to open, detect closure of, and manage the tabs this extension creates
storage — to remember your settings and theme locally