---
title: "RegEx PDF redaction on iOS | Nutrient SDK"
canonical_url: "https://www.nutrient.io/guides/ios/redaction/regex-patterns/"
md_url: "https://www.nutrient.io/guides/ios/redaction/regex-patterns.md"
last_updated: "2026-06-09T10:25:14.476Z"
description: "Nutrient enables you to redact text in a PDF document using regular expression patterns. Learn to redact URLs in a document using NSRegularExpression."
---

# Using RegEx to redact PDFs on iOS

Nutrient enables you to redact text in a PDF document using regular expression patterns. This guide shows how to redact URLs in a document using [`NSRegularExpression`](https://developer.apple.com/documentation/foundation/nsregularexpression).

First, you need to create the regular expression with the URL pattern:

```swift

let urlPattern = #"[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)"#

let urlRegularExpression = try! NSRegularExpression(pattern: urlPattern)

```

Then, you’ll have to loop through all the pages in the document to find and mark the matching URLs for redaction. To get the text in the document, you’ll need to use [`TextParser`](https://www.nutrient.io/api/ios/documentation/pspdfkit/textparser), which you can access via the [`Document`](https://www.nutrient.io/api/ios/documentation/pspdfkit/document)’s [`textParserForPage(at:)`](https://www.nutrient.io/api/ios/documentation/pspdfkit/document/textparserforpage(at:)) method:

```swift

let fileURL = Bundle.main.url(forResource: "Document", withExtension: "pdf")!
let document = Document(url: fileURL)

for pageIndex in 0..<document.pageCount {
    if let textParser = document.textParserForPage(at: pageIndex) {
        textParser.words.forEach { word in
            let wordString = word.stringValue
            let range = NSRange(wordString.startIndex..<wordString.endIndex, in: wordString)

            // Redact all the words that match the regex.
            let isValidURL = urlRegularExpression.numberOfMatches(in: wordString, options: [], range: range) > 0
            if isValidURL {
                // Create a redaction annotation for each URL and add it to the document.
                let redactionRect = word.frame
                let redaction = RedactionAnnotation()
                redaction.boundingBox = redactionRect
                redaction.rects = [redactionRect]
                redaction.color =.orange
                redaction.fillColor =.black
                redaction.overlayText = "REDACTED"
                redaction.pageIndex = pageIndex
                document.add(annotations: [redaction])
            }
        }
    }
}

```

And finally, create a new PDF file for the redacted document by applying redactions using the [`Processor`](https://www.nutrient.io/api/ios/documentation/pspdfkit/processor) API, instantiate a [`Document`](https://www.nutrient.io/api/ios/documentation/pspdfkit/document) object, and present it in a [`PDFViewController`](https://www.nutrient.io/api/ios/documentation/pspdfkitui/pdfviewcontroller), like so:

```swift

// Use Processor to create the newly redacted document.
let processorConfiguration = Processor.Configuration(document: document)!

// Apply redactions to permanently redact URLs from the document.
processorConfiguration.applyRedactions()

let processor = Processor(configuration: processorConfiguration, securityOptions: nil)
try? processor.write(toFileURL: redactedDocumentURL)

// Instantiate the redacted document and present it.
let redactedDocument = Document(url: redactedDocumentURL)
let pdfController = PDFViewController(document: redactedDocument)
present(UINavigationController(rootViewController: pdfController), animated: true)

```





For more details about redacting a document using regular expressions, refer to [`RedactTextUsingRegexExample.swift`](https://github.com/PSPDFKit/pspdfkit-ios-catalog/blob/master/Catalog/Examples/DocumentProcessing/RedactTextUsingRegexExample.swift) in the [Nutrient Catalog](https://github.com/PSPDFKit/pspdfkit-ios-catalog) app.
---

## Related pages

- [Redacting PDFs in iOS viewer](/guides/ios/redaction/built-in-ui.md)
- [PDF redaction library for iOS](/guides/ios/redaction.md)
- [Redact PDFs with Nutrient iOS SDK](/guides/ios/redaction/introduction-to-redaction.md)
- [Search and redact PDFs on iOS](/guides/ios/redaction/search-and-redact.md)
- [Redacting PDFs programmatically on iOS](/guides/ios/features/redaction.md)