@capgo/capacitor-nfc

Native NFC tag detection, reading, and writing for Capacitor apps on iOS and Android.

Modern Capacitor port of the battle-tested phonegap-nfc plugin, aligned with Capgo conventions and tooling.

Supported Tag Types

• Standard NFC Forum Tags (Type 1-4)
• MIFARE Ultralight - Full support for reading NDEF data from MIFARE Ultralight tags, including EV1 and NTAG variants. The plugin automatically detects MIFARE Ultralight cards and extracts NDEF messages in addition to standard NFC tags.

Documentation

The most complete documentation will live on the Capgo docs portal. Until then, explore the TypeScript definitions (src/definitions.ts) and run the included example app for a tour of the API.

Install

npm install @capgo/capacitor-nfc
npx cap sync

Remember to add the required platform configuration:

• Android: ensure your AndroidManifest.xml declares the android.permission.NFC permission.
• iOS: add NFCReaderUsageDescription to your app Info.plist to explain why NFC access is needed.

Usage

import { CapacitorNfc } from '@capgo/capacitor-nfc';

await CapacitorNfc.startScanning({
  invalidateAfterFirstRead: false, // keep the session open so we can write later
  alertMessage: 'Hold a tag near the top of your device.',
});

const listener = await CapacitorNfc.addListener('nfcEvent', (event) => {
  console.info('Tag type:', event.type);
  console.info('First record:', event.tag?.ndefMessage?.[0]);
});

// Later, write a simple text record back to the tag
const encoder = new TextEncoder();
const langBytes = Array.from(encoder.encode('en'));
const textBytes = Array.from(encoder.encode('Hello Capgo'));
const payload = [langBytes.length & 0x3f, ...langBytes, ...textBytes];

await CapacitorNfc.write({
  allowFormat: true,
  records: [
    {
      tnf: 0x01,
      type: [0x54], // 'T'
      id: [],
      payload,
    },
  ],
});

await listener.remove();
await CapacitorNfc.stopScanning();

API

• startScanning(...)
• stopScanning()
• write(...)
• erase()
• makeReadOnly()
• share(...)
• unshare()
• getStatus()
• showSettings()
• getPluginVersion()
• addListener('nfcEvent', ...)
• addListener('tagDiscovered' | 'ndefDiscovered' | 'ndefMimeDiscovered' | 'ndefFormatableDiscovered', ...)
• addListener('nfcStateChange', ...)
• Interfaces
• Type Aliases

Public API surface for the Capacitor NFC plugin.

The interface intentionally mirrors the behaviour of the reference PhoneGap implementation to ease migration while embracing idiomatic Capacitor APIs.

startScanning(...)

startScanning(options?: StartScanningOptions | undefined) => Promise<void>

Starts listening for NFC tags.

| Param | Type | | ------------- | --------------------------------------------------------------------- | | options | StartScanningOptions |

stopScanning()

stopScanning() => Promise<void>

Stops the ongoing NFC scanning session.

write(...)

write(options: WriteTagOptions) => Promise<void>

Writes the provided NDEF records to the last discovered tag.

| Param | Type | | ------------- | ----------------------------------------------------------- | | options | WriteTagOptions |

erase()

erase() => Promise<void>

Attempts to erase the last discovered tag by writing an empty NDEF message.

makeReadOnly()

makeReadOnly() => Promise<void>

Attempts to make the last discovered tag read-only.

share(...)

share(options: ShareTagOptions) => Promise<void>

Shares an NDEF message with another device via peer-to-peer (Android only).

| Param | Type | | ------------- | ----------------------------------------------------------- | | options | ShareTagOptions |

unshare()

unshare() => Promise<void>

Stops sharing previously provided NDEF message (Android only).

getStatus()

getStatus() => Promise<{ status: NfcStatus; }>

Returns the current NFC adapter status.

Returns: Promise<{ status: NfcStatus; }>

showSettings()

showSettings() => Promise<void>

Opens the system settings page where the user can enable NFC.

getPluginVersion()

getPluginVersion() => Promise<{ version: string; }>

Returns the version string baked into the native plugin.

Returns: Promise<{ version: string; }>

addListener('nfcEvent', ...)

addListener(eventName: 'nfcEvent', listenerFunc: (event: NfcEvent) => void) => Promise<PluginListenerHandle>

| Param | Type | | ------------------ | ----------------------------------------------------------------- | | eventName | 'nfcEvent' | | listenerFunc | (event: NfcEvent) => void |

Returns: Promise<PluginListenerHandle>

addListener('tagDiscovered' | 'ndefDiscovered' | 'ndefMimeDiscovered' | 'ndefFormatableDiscovered', ...)

addListener(eventName: 'tagDiscovered' | 'ndefDiscovered' | 'ndefMimeDiscovered' | 'ndefFormatableDiscovered', listenerFunc: (event: NfcEvent) => void) => Promise<PluginListenerHandle>

| Param | Type | | ------------------ | ------------------------------------------------------------------------------------------------------ | | eventName | 'tagDiscovered' | 'ndefDiscovered' | 'ndefMimeDiscovered' | 'ndefFormatableDiscovered' | | listenerFunc | (event: NfcEvent) => void |

Returns: Promise<PluginListenerHandle>

addListener('nfcStateChange', ...)

addListener(eventName: 'nfcStateChange', listenerFunc: (event: NfcStateChangeEvent) => void) => Promise<PluginListenerHandle>

| Param | Type | | ------------------ | --------------------------------------------------------------------------------------- | | eventName | 'nfcStateChange' | | listenerFunc | (event: NfcStateChangeEvent) => void |

Returns: Promise<PluginListenerHandle>

Interfaces

StartScanningOptions

Options controlling the behaviour of {@link CapacitorNfcPlugin.startScanning}.

| Prop | Type | Description | | ------------------------------ | -------------------- | ------------------------------------------------------------------------------------------------------------------------------ | | invalidateAfterFirstRead | boolean | iOS-only: closes the NFC session automatically after the first successful tag read. Defaults to true. | | alertMessage | string | iOS-only: custom message displayed in the NFC system sheet while scanning. | | androidReaderModeFlags | number | Android-only: raw flags passed to NfcAdapter.enableReaderMode. Defaults to enabling all tag types with skipping NDEF checks. |

WriteTagOptions

Options used when writing an NDEF message on the current tag.

| Prop | Type | Description | | ----------------- | ------------------------- | ---------------------------------------------------------------------------------------------------- | | records | NdefRecord[] | Array of records that compose the NDEF message to be written. | | allowFormat | boolean | When true, the plugin attempts to format NDEF-formattable tags before writing. Defaults to true. |

NdefRecord

JSON structure representing a single NDEF record.

Mirrors the data format returned by the legacy Cordova implementation and uses integer arrays instead of strings to preserve the original payload bytes.

| Prop | Type | Description | | ------------- | --------------------- | ------------------------------------------------------- | | tnf | number | Type Name Format identifier. | | type | number[] | Type field expressed as an array of byte values. | | id | number[] | Record identifier expressed as an array of byte values. | | payload | number[] | Raw payload expressed as an array of byte values. |

ShareTagOptions

Options used when sharing an NDEF message with another device using Android Beam / P2P mode.

| Prop | Type | | ------------- | ------------------------- | | records | NdefRecord[] |

PluginListenerHandle

| Prop | Type | | ------------ | ----------------------------------------- | | remove | () => Promise<void> |

NfcEvent

Generic NFC discovery event dispatched by the plugin.

| Prop | Type | | ---------- | ----------------------------------------------------- | | type | NfcEventType | | tag | NfcTag |

NfcTag

Representation of the full tag information returned by the native layers.

Supports standard NFC Forum tags as well as MIFARE Ultralight cards (including EV1 and NTAG variants). NDEF data is automatically extracted from MIFARE Ultralight tags when available.

| Prop | Type | Description | | --------------------- | --------------------------------- | -------------------------------------------------------------------------------------- | | id | number[] | Raw identifier bytes for the tag. | | techTypes | string[] | List of Android tech strings (e.g. android.nfc.tech.Ndef). | | type | string | null | Human readable tag type when available (e.g. NFC Forum Type 2, MIFARE Ultralight). | | maxSize | number | null | Maximum writable size in bytes for tags that expose NDEF information. | | isWritable | boolean | null | Indicates whether the tag can be written to. | | canMakeReadOnly | boolean | null | Indicates whether the tag can be permanently locked. | | ndefMessage | NdefRecord[] | null | Array of NDEF records discovered on the tag. |

NfcStateChangeEvent

Event emitted whenever the NFC adapter availability changes.

| Prop | Type | | ------------- | ----------------------------------------------- | | status | NfcStatus | | enabled | boolean |

Type Aliases

NfcStatus

Possible NFC adapter states returned by {@link CapacitorNfcPlugin.getStatus}.

Matches the constants provided by the original PhoneGap NFC plugin for compatibility with existing applications.

'NFC_OK' | 'NO_NFC' | 'NFC_DISABLED' | 'NDEF_PUSH_DISABLED'

NfcEventType

Event type describing the kind of NFC discovery that happened.

• tag: A generic NFC tag (no NDEF payload).
• ndef: A tag exposing an NDEF payload.
• ndef-mime: An NDEF tag that matched one of the MIME type filters.
• ndef-formatable: A tag that can be formatted to NDEF.

'tag' | 'ndef' | 'ndef-mime' | 'ndef-formatable'