List A minus list B
Remove every item of list B from list A to get the difference A−B — separate the two lists with a `---` divider line (configurable), with optional case/whitespace folding, duplicate collapsing, code-point sorting and A/B/removed counts.
Runs in your browserEvery computation happens in your browser — your data never leaves this device.
Difference (A − B)
One item per line, ready to copy.
Paste both lists to compute A − B
Items in A: 0 · Items in B: 0 · Kept: 0 · Removed: 0 · Collapsed: 0
What this tool does
- Blacklist check: use the full list as A and the excluded IDs as B to get the remaining recipients.
- Clean up processed records: A is the backlog, B is what is already done, and the difference is what remains.
- Reconcile two exports by looking at what only the first list contains.
Example
Input
apple banana cherry durian --- banana durian
Output
apple cherry
Everything above the `---` divider is list A, everything below is list B; banana and durian are removed and the rest keeps its original order.
Frequently asked questions
How do I separate the two lists?
With a single `---` line: everything above it is list A, everything below is list B, and that line is not compared. If it is missing, list B counts as empty and the output equals A. The divider text is configurable.
Are duplicates in A kept?
Yes, by default. The difference only decides keep-or-remove, so duplicates survive unless you turn on “Remove duplicates”, which keeps the first occurrence and reports how many were collapsed.
Does case matter?
No, not by default. Turn on “Ignore case” and Apple and apple count as the same item — the comparison is folded, but the output keeps A's original spelling.
Does a huge list B slow it down?
No. B is collapsed into a lookup set first, so duplicates are scanned once. A and B are capped at 200,000 lines each and report an error beyond that instead of freezing the tab.
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