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Flinks Upload automatically analyzes uploaded bank statements for signs of tampering or manipulation. When suspicious indicators are found, fraud signals are returned in the response to help you make informed decisions.

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Fraud signal list

The following signals may be detected during document analysis:

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Most common signals

The three most frequently triggered signals are:
  1. Unreconciled balances: Running totals don’t add up when recalculated from individual transactions
  2. Unusual document source: The PDF producer or creator doesn’t match known bank output
  3. Editing software detected: The document metadata references editing tools

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Document support

Fraud analysis is only available for bank statements. Void cheques are processed for data extraction only.

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Understanding false positives

Not every fraud signal indicates actual fraud. Some legitimate user behaviors can trigger signals. When users print their bank statement to PDF instead of downloading the original file, the resulting document may trigger fraud signals. Common print-to-PDF producers include:
  • PDFium (Chrome’s built-in PDF printer)
  • Microsoft Print to PDF (Windows)
  • macOS Quartz PDFContext (macOS print dialog)
These tools modify the document’s metadata and structure, which can trigger the “Unusual document source” and “Editing software detected” signals even though the content hasn’t been tampered with.

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Actual fraud indicators

The following editing tools in document metadata are stronger indicators of manipulation:
  • PDF Filler
  • Sejda
  • iLovePDF
  • Adobe Acrobat Pro (when used for editing, not just viewing)
  • Other general-purpose PDF editing tools
When these tools appear alongside signals like dollar amount edits, description edits, or unreconciled balances, the likelihood of tampering is significantly higher.

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Best practices

Encourage direct downloads. Ask your users to download their bank statements directly from their financial institution’s website or mobile app. This produces the cleanest documents and minimizes false positives.
  • Don’t auto-reject on a single signal. A single fraud signal (especially “unusual document source” alone) may be a false positive. Look for combinations of signals.
  • Prioritize balance reconciliation. Unreconciled balances combined with dollar amount edits is a strong indicator of tampering.
  • Review the document source. Check whether the PDF producer is a known print-to-PDF tool or a dedicated editing tool.
  • Use the fraud verdict. Flinks provides an overall fraud verdict, Trust, Normal, Warning, or High Risk, that considers the combination of signals. Use this as your primary decision point.

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Accessing fraud data

Fraud signals are available through:
  • The Fraud Analysis API endpoint
  • The Flinks Dashboard (visual review)
  • Webhook notifications (if configured)