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Cold email duplicate contact checker
Find repeated email values in a pasted CSV without deleting, merging or uploading contacts.
Prepare your inputs
Include an Email column. Matching trims surrounding whitespace and lowercases the whole address. This practical rule is shown explicitly because different systems can use different identity policies.
Runs in this browser. Inputs are not sent by this tool or saved in browser storage. Start with the fictional example; use redacted text for reviews.
How it works
The utility keeps the first logical row for each plausible address and reports later matching rows. It does not remove plus tags, dots or infer that two different addresses belong to the same person.
Worked example
[email protected] and [email protected] are flagged as a repeated value under this rule. [email protected] remains a separate address, and no company-level merge is inferred.
Limits and interpretation
Inspect the underlying records before choosing a survivor. A duplicate row may carry a newer exclusion or important source evidence. The checker produces a review list, not a destructive cleanup.
Examples are synthetic, not customer results. Zintara practical guide library