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About this tool
Analyze browser tab sessions, detect duplicates, categorize domains, and get productivity insights to clean up your browsing.
Browser Session Analyzer takes a list of open tab URLs — pasted, or exported as JSON or CSV from a session manager — and reports how many are duplicates, which domains dominate, what the tabs are actually for, and roughly how much memory they cost. It is for people who habitually run 80 tabs and want a defensible list of what to close. Duplicates are matched on the normalised URL (lower-cased, with the hash, query string and trailing slash stripped), so twenty copies of the same article arriving via different UTM links collapse into one.
Open Browser Session Analyzer on AltFTool — it loads instantly in your browser.
Paste a JSON tab export, a plain list of URLs or a bookmark export into the Import Session Data box and press Analyze, use Import File for a .json, .csv, .txt or .html file, or type one address into 'Enter URL manually...' and press Add.
The parse runs immediately and fills the dashboard: Total Tabs, Unique Domains, Duplicates, Broken URLs, HTTP (not HTTPS) and Est. Memory, plus Health, Focus and Clutter meters, with every tab tagged Development, Social Media, Research and so on.
Filter by clicking a category pill or typing in 'Search URLs, domains, categories...', re-order with the Order / Domain / Category select, and snapshot the current tab list under Groups, where each group can be renamed, collapsed or deleted. Open Export for Export JSON, Export CSV, Export TXT or Copy as JSON — Clear empties the session.
URLs are normalised before comparison, so ?utm_source= and #anchor copies of one page are counted as one.
Around 150 well-known domains are pre-classified into 14 groups — AI, Development, Research, Social Media, Entertainment and more — with no setup.
The URL list is parsed in the page; nothing is uploaded, which matters because a tab list is a detailed record of what you have been reading.
It starts at 100 and subtracts 5 points per duplicate URL and 10 per malformed URL, then 0.5 per tab above 50 and a further 0.3 per tab above 100, clamped to 0-100. So 60 clean tabs score 95, and 120 clean tabs score 59. The 50-tab knee is where Chrome typically begins discarding background tabs on an 8 GB machine.
It is ((productive − 0.5 × distracting) / total) × 50 + 50. An all-productive session scores 100, an even split scores 50 and an all-distracting session scores 25. Productive means Development, Productivity, Education and Research; distracting means Entertainment, Social Media, Shopping and Gaming. Uncategorised domains land in Other and pull the score toward 50.
It is a planning estimate, not a measurement: 50 MB per tab plus 150 MB extra for a tab on YouTube or Netflix. Chrome's own task manager puts a typical content-heavy tab in the 40-60 MB band once renderer, compositor and page heap are counted. For a real per-tab number use Shift+Esc in Chrome or about:performance in Firefox.
Three, auto-detected. A plain list of URLs one per line; a CSV column of URLs; or JSON in any of the common shapes — a bare array of strings, an array of objects with a url field, or an object with a tabs, urls or bookmarks key. Nested bookmark trees are walked recursively, so a Chrome bookmarks export works as-is.