CoreNFC

Read and write NFC tags on iPhone using the CoreNFC framework. Covers NDEF reader sessions, tag reader sessions, NDEF message construction, entitlements, and background tag reading. Targets Swift 6.3 / iOS 26+.

Contents

• Setup
• NDEF Reader Session
• Tag Reader Session
• Writing NDEF Messages
• NDEF Payload Types
• Background Tag Reading
• Common Mistakes
• Review Checklist
• References

Setup

Project Configuration

1. Add the Near Field Communication Tag Reading capability in Xcode
2. Add NFCReaderUsageDescription to Info.plist with a user-facing reason string
3. Add the com.apple.developer.nfc.readersession.formats entitlement with the tag types your app reads (e.g., NDEF, TAG)
4. For ISO 7816 tags, add supported application identifiers to com.apple.developer.nfc.readersession.iso7816.select-identifiers in Info.plist

Device Requirements

NFC reading requires iPhone 7 or later. Always check for reader session availability before presenting NFC UI.

import CoreNFC

guard NFCNDEFReaderSession.readingAvailable else {
    // Device does not support NFC or feature is restricted
    showUnsupportedMessage()
    return
}

Key Types

NDEF Reader Session

Use NFCNDEFReaderSession to read NDEF-formatted data from tags. This is the simplest path for reading standard tag content like URLs, text, and MIME data.

import CoreNFC

final class NDEFReader: NSObject, NFCNDEFReaderSessionDelegate {
    private var session: NFCNDEFReaderSession?

    func beginScanning() {
        guard NFCNDEFReaderSession.readingAvailable else { return }

        session = NFCNDEFReaderSession(
            delegate: self,
            queue: nil,
            invalidateAfterFirstRead: false
        )
        session?.alertMessage = "Hold your iPhone near an NFC tag."
        session?.begin()
    }

    // MARK: - NFCNDEFReaderSessionDelegate

    func readerSessionDidBecomeActive(_ session: NFCNDEFReaderSession) {
        // Session is scanning
    }

    func readerSession(
        _ session: NFCNDEFReaderSession,
        didDetectNDEFs messages: [NFCNDEFMessage]
    ) {
        for message in messages {
            for record in message.records {
                processRecord(record)
            }
        }
    }

    func readerSession(
        _ session: NFCNDEFReaderSession,
        didInvalidateWithError error: Error
    ) {
        let nfcError = error as? NFCReaderError
        if nfcError?.code != .readerSessionInvalidationErrorFirstNDEFTagRead,
           nfcError?.code != .readerSessionInvalidationErrorUserCanceled {
            print("Session invalidated: \(error.localizedDescription)")
        }
        self.session = nil
    }
}

Reading with Tag Connection

For read-write operations, use the tag-detection delegate method to connect to individual tags:

func readerSession(
    _ session: NFCNDEFReaderSession,
    didDetect tags: [any NFCNDEFTag]
) {
    guard let tag = tags.first else {
        session.restartPolling()
        return
    }

    session.connect(to: tag) { error in
        if let error {
            session.invalidate(errorMessage: "Connection failed: \(error)")
            return
        }

        tag.queryNDEFStatus { status, capacity, error in
            guard error == nil else {
                session.invalidate(errorMessage: "Query failed.")
                return
            }

            switch status {
            case .notSupported:
                session.invalidate(errorMessage: "Tag is not NDEF compliant.")
            case .readOnly:
                tag.readNDEF { message, error in
                    if let message {
                        self.processMessage(message)
                    }
                    session.invalidate()
                }
            case .readWrite:
                tag.readNDEF { message, error in
                    if let message {
                        self.processMessage(message)
                    }
                    session.alertMessage = "Tag read successfully."
                    session.invalidate()
                }
            @unknown default:
                session.invalidate()
            }
        }
    }
}

Tag Reader Session

Use NFCTagReaderSession when you need direct access to the native tag protocol (ISO 7816, ISO 15693, FeliCa, or MIFARE).

final class TagReader: NSObject, NFCTagReaderSessionDelegate {
    private var session: NFCTagReaderSession?

    func beginScanning() {
        session = NFCTagReaderSession(
            pollingOption: [.iso14443, .iso15693],
            delegate: self,
            queue: nil
        )
        session?.alertMessage = "Hold your iPhone near a tag."
        session?.begin()
    }

    func tagReaderSessionDidBecomeActive(
        _ session: NFCTagReaderSession
    ) { }

    func tagReaderSession(
        _ session: NFCTagReaderSession,
        didDetect tags: [NFCTag]
    ) {
        guard let tag