Credit Card Extractor: Find Card-Number Candidates in Text
The Credit Card Extractor scans text for digit runs containing 12–19 digits, with optional single spaces or hyphens. It checks each candidate with the Luhn checksum and labels a matching network as Visa, Mastercard, American Express, Diners Club, Discover, JCB, UnionPay, Maestro, or Unknown. These checks do not confirm that a number is issued, active, authorized, or chargeable.
How to Use the Credit Card Extractor
- Paste text into the input area, or use Upload or Drop file. The file picker accepts
.txt,.csv,.json, and.logfiles, which are read as text. - Review the results table. Its columns are Number, Network, Status, Line, and Context.
- Change the checkboxes as needed. Results update when the input or checkbox settings change.
- Review the read-only output textarea, then use Copy or Download. Downloads use the filename
card-numbers.txt.
Read the Results and Adjust the Controls
The table marks each displayed candidate as Luhn valid or Luhn invalid. Line is calculated by counting newline characters before the match. Context is a short, normalized snippet from nearby text, not the complete source location.
- Unique only compares normalized digits after removing spaces and hyphens. When duplicates are removed, the first retained match supplies the displayed line and context.
- Show Luhn-invalid candidates controls invalid candidates in the table, output, count, copied text, and downloaded file. Turn it off to keep only Luhn-valid candidates.
- Mask numbers (show last 4 digits only) masks displayed and exported values when enabled. The input text remains in the page.
- The counter reports the current total, including the Luhn-valid and invalid counts. With no matches, it reports
0 candidates.
Matching Limits and Validation Warnings
The matcher scans digit runs with optional single spaces or hyphens and 12–19 digits in total. This implementation does not establish that every payment-card format is covered. Candidates outside its hard-coded network patterns receive the label Unknown.
A Luhn result is only a checksum result. The tool does not contact a card network, issuer, bank, or payment processor, and does not verify an account, funds, authorization, or active status.
Privacy and Handling of Card Data
Extraction, checksum validation, and rendering run in browser JavaScript. Uploaded files are read into the page as text. Masking changes the values shown in the table and output, but it does not remove the original text from the input area. Handle live cardholder data according to applicable policies and clear the input when finished. No maximum input or upload size is documented for this tool.
Frequently Asked Questions (FAQs)
Does a "Luhn valid" result mean the card is real or active?
No. Luhn is a checksum result, not proof that a number belongs to an issued, active, or chargeable account. This tool makes no network calls to an issuer, processor, or bank, so it cannot confirm whether a number is real.
Is it safe to paste real card numbers into this tool?
Extraction, checksum validation, and rendering run in browser JavaScript, and uploaded files are read into the page as text. Masking changes displayed and output values, but the input remains in the page. Handle live cardholder data according to applicable policies and clear the input when done.
What card networks does the extractor detect?
The tool checks hard-coded prefix and length patterns for Visa, Mastercard, American Express, Discover, Diners Club, JCB, UnionPay, and Maestro. Candidates outside those patterns are labeled Unknown.
Does Unique only work across differently formatted duplicates?
Yes. When Unique only is enabled, deduplication compares normalized digits after spaces and hyphens are removed. The first retained match supplies the displayed line and context.
Can this tool verify a card account?
No. It extracts candidates from text, checks the Luhn checksum, and applies its network patterns. It does not verify an account, issuer, funds, authorization, or whether a number is active.