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Sender Score vs MultiRBL: catalog facts
Sender Score	MultiRBL
Free The score lookup and related tools are offered free by Validity.	Free Free to use, with optional Bitcoin donations.
Web	Web
Quick reputation score for an IP address or domain Return Path Blocklist lookup and removal request in one place	Checks over 200 blacklists and whitelists Supports IPv4 and IPv6
Site also promotes Validity's paid email services Score reflects Validity's own data rather than every mailbox provider	No help with removal requests Plain interface with lots of technical output
Web application	Web application
Closed source	Closed source
License not stated	License not stated
Not stated if an account is needed	No account needed
Needs internet	Needs internet
Official website Full listing and sources Checked September 24, 2026	Official website Full listing and sources Checked September 23, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.