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How to make a Wi-Fi NFC tag on iPhone

Updated

A Wi-Fi NFC tag stores your network name, security type and password, so guests don't have to type a long password. Writing one with an iPhone takes about a minute. Before you print a sign for it, it's worth knowing how different phones react to the tag, because that's the part most guides get wrong.

What you need

  • An iPhone with NFC Toolkit. Writing Wi-Fi records is free.
  • A blank NFC tag. An NTAG213 (144 bytes of user memory) is enough for most networks: a Wi-Fi record with a normal name and password is usually under 100 bytes. Pick an NTAG215 if your network name and password are long or you want to add a second record.
  • Your network name and password, exactly as configured on the router. Ideally use a separate guest network (more on that below).

What happens when someone taps the tag

The tag holds a standard Wi-Fi record (the Wi-Fi Alliance "WSC" format, MIME type application/vnd.wfa.wsc). Phones handle it differently:

  • Android: most Android phones recognise the Wi-Fi record and offer to connect to the network. The exact prompt and behaviour depend on the manufacturer and Android version, so test with the phones your guests are likely to use.
  • iPhone: the iPhone's built-in tag reader only acts on links: websites, phone numbers, email, SMS, FaceTime and Maps. It does not act on Wi-Fi records, so tapping a Wi-Fi tag with an iPhone usually does nothing unless an NFC app is open. iOS never joins a network silently from a tag. With an NFC app such as NFC Toolkit, the guest sees the network name and can copy the password, then join in Settings › Wi-Fi.

Cover iPhone guests with a QR code. The iPhone Camera recognises Wi-Fi QR codes and shows a prompt to join the network. Putting a QR code next to the tag means Android guests can tap and iPhone guests can scan. A Wi-Fi QR code encodes text such as WIFI:T:WPA;S:YourNetwork;P:YourPassword;;. It contains your password, so create it with a generator you trust, ideally one that runs offline.

Step by step: write the tag with NFC Toolkit

  1. Open the Write tab. Open NFC Toolkit and go to the Write tab.
  2. Choose the template. Under Quick start, tap Wi-Fi guest card.
  3. Enter the network name. Type the Network name (SSID) exactly as your router broadcasts it. Capitals and spaces count.
  4. Pick the security type. Choose WPA2, WPA/WPA2 or Open network, then enter the password (open networks don't need one).
  5. Check the size. Tap Done. The record appears under Records and the size meter shows how many bytes it needs. Leave Tag size on Auto-detect or pick your tag type.
  6. Write the tag. Tap Write to tag and hold the top of your iPhone flat against the tag until you see Written successfully.
  7. Test it. Scan the tag from the Scan tab to confirm the network name, then try it with an Android phone if you have one.

If the size meter turns red, the record is too large for the selected tag. Use a bigger tag rather than shortening the password.

Choosing and placing the tag

  • Format: stickers are cheapest and fit under a printed sign or inside a frame. Ready-made Wi-Fi stands and cards are the same chip in a nicer case; check the listing says NTAG213, 215 or 216.
  • Not on metal: a standard tag stuck directly on metal (a fridge, a metal sign, an aluminium counter) usually won't read, because the metal interferes with the antenna. Use a tag sold as "on-metal" or "anti-metal" for those surfaces.
  • Short range: NFC works over a few centimetres. Thin paper, card, plastic or wood over the tag is fine; thick glass or anything metallic is not.
  • Label it: "Tap your phone here for Wi-Fi", the network name in plain text, and the QR code. Mention that iPhone users should hold the top of the phone to the sign.

Keep it secure

  • The password is readable. Anyone who taps the tag with an NFC app can read the password; tags don't encrypt their contents. Put your guests on a guest network that is separated from your own computers, cameras and smart-home devices.
  • Prevent tampering. A writable tag in a public place can be overwritten by anyone with an NFC writer app. With NFC Toolkit's Pro tools you can password-protect the tag, so it stays readable but can only be rewritten with your password (4 characters or 8 hex digits), or lock it permanently.
  • Lock or password? If you change your guest password from time to time, use password protection so you can rewrite the tag later. A locked tag can never be changed, so a new Wi-Fi password would mean a new tag. Leave "Also require it to read" off, otherwise guests can't read the tag at all.

Pro tools can be used once by watching a short ad, or unlocked for good with a one-time purchase.

Troubleshooting

  • "Too large for the selected tag": use an NTAG215 or NTAG216.
  • Android doesn't offer to connect: check that NFC is turned on in the phone's settings, that the network name matches exactly (it's case-sensitive), and that the security type is right.
  • Connects but no internet: the tag did its job; check the router or guest network settings.
  • An iPhone does nothing: expected without an NFC app; see above and add a QR code.
  • WPA3-only networks: NFC Toolkit writes WPA2, WPA/WPA2 or open network records. If your guest network is WPA3-only, test with a guest phone before printing, or run the guest network in a WPA2/WPA3 mixed mode.

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