Compare two lists of websites and see exactly what they share.
Paste one list in each box. You get back the sites that appear in both, the sites that appear in only one, an overlap summary, and everything grouped by domain ending. Formatting doesn't matter — abc.com, www.abc.com and https://abc.com/blog all count as the same site.
Your lists never leave this page. The comparison runs inside your own browser — nothing is uploaded, stored or logged.
What each table tells you
Similar
Every site that appears in both lists. If your lists carry Niche, Score, Status or Last Active columns, it keeps the better of the two rows — and flags anyone already marked as contacted.
Different
Every site that appears in only one list, with list A on the left and list B on the right so you can see at a glance where each one came from.
Overlap Summary & By Extension
The counts — how many in each list, how many shared, and the overlap percentage. Then every site grouped by ending: .com, .org, .co.uk and the rest, side by side.
Why you would use it
If you build prospect lists, you end up with lists that partly repeat each other — a list from last month, a list a supplier sent, a list a client already worked through. Pitching the same editor twice is the fastest way to get ignored. This tells you which sites you have already got before you spend an email on them.
It also answers the plainer questions: how much do these two lists actually overlap, which sites are genuinely new, and how many of them are .com versus .org.
What counts as the same site
Protocol, www., paths, query strings, ports and capitals are all ignored, so ABC.com, www.abc.com and https://abc.com/write-for-us match each other. Subdomains are kept separate: blog.abc.com and abc.com are treated as two different sites, because for guest posting they often are.
Also free, also no account — check whether an address is worth pitching before you send.