Longest common substring

Client

Contiguous match length for log diffing.

About Longest common substring

Find longest contiguous shared substring. Processing runs in your browser—Toolcore does not need your paste for the core operation on this page.

Deterministic string metrics only; rephrased text may score differently than human judgment.

How to use

Paste or type in the main field, then read the output below. Use Load example when available, or open the page with ?q= / ?qb= so tickets and agents share the same input.

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Nearby workflows on Toolcore

  • Levenshtein distance — Compare two strings for edit distance and similarity score—local Levenshtein calculator. Useful when a second similarity metric helps decide deduplication.
  • Jaccard similarity — Word-token Jaccard index between two texts—optional case folding, in your browser. Useful when a second similarity metric helps decide deduplication.
  • Overlapping lines — List lines that appear in both multiline texts. Useful when a second similarity metric helps decide deduplication.
  • Plain text diff — Compare two text drafts side by side—unified view, sample pre-filled, client-side. Useful when a second similarity metric helps decide deduplication.

Common use cases

  • Longest common substring for quick local checks without uploading data.
  • Copy results into tickets, docs, or classroom notes.

Common mistakes to avoid

  • Unexpected input shape

    See the intro and how-to notes for accepted formats.

FAQ

Is processing local?

Yes—this runs entirely in your browser.

Agent prefill?

Use q or qb for the main text field when supported.

More tools

Related utilities you can open in another tab—mostly client-side.