Wi-Fi QR Codes: How They Work and How to Make One Safely

What is inside a Wi-Fi QR code

There is no special "Wi-Fi" kind of QR Code. It is the same symbol used for links, and the data is a line of plain text in a format that phones recognize. The format is not an official standard with its own spec. The ZXing project's Barcode Contents wiki proposes it, and Android and iOS 11 and later phones read it.

The text looks like this:

WIFI:T:WPA;S:Cafe Guest;P:Fresh-Beans-42;;

Each piece is a field followed by a value, separated by semicolons, with two semicolons at the end:

Because the password sits in the text in readable form, anyone who decodes the code sees it. A QR code is not encrypted.

Special characters need a backslash

The semicolon, comma, colon, double quote and backslash have meaning in this format. According to the ZXing wiki, if your network name or password contains any of them, you put a backslash in front of that character.

Suppose the password is Fresh;Beans. The payload becomes:

WIFI:T:WPA;S:Cafe Guest;P:Fresh\;Beans;;

Without the backslash, the semicolon ends the password field early, so the code may scan but fail to join. Behavior varies by phone. The ZXing wiki also says a name or password that is plain ASCII but could be read as hex, such as ABCD, should be wrapped in double quotes; this site's generator does not add those quotes. The Plain Barcode QR code generator adds these backslashes for you when you choose the Wi-Fi option.

How phones use the code

On most Android phones you can create a code from the saved network. Android Police describes the path on a Pixel as Settings, Network and internet, Internet, then the cog beside your network and Share, after a biometric or PIN check. On a Samsung phone it is the QR code option on the network's settings screen. Menus vary by maker and software version, and that article dates from 2023, so treat these paths as a starting point.

The same article says the other phone scans the code and joins. On an iPhone, Apple's instructions for scanning a QR code say Camera reads it in Photo mode and shows a link at the bottom of the screen; they don't mention Wi-Fi specifically. The ZXing wiki lists the Wi-Fi format as working on Android and iOS 11 and later. Older or unusual devices may show the raw text instead of an offer to join.

Don't assume it works everywhere. Before you print, scan your own code with at least one iPhone and one Android phone, on a device that is not already connected to the network.

One thing to know about sharing from your own phone: on a Pixel the password appears below the code, while Samsung's screen shows only the code, according to Android Police. Either way, the password is inside the code.

Put the code on a guest network

Because anyone who sees the code can join, the code should never open your main network. CISA's wireless security guidance describes a guest network as a way to give visitors access on a separate wireless channel with a separate password, which keeps your primary credentials private. Many routers offer this feature.

A short checklist for the guest network:

1. Create a guest network with its own name and password in your router settings.
2. Choose the strongest security the router and your guests' devices support. The Wi-Fi Alliance says WPA3 networks use the latest security protocols, and CISA recommends equipment that supports WPA3. If your router offers a mixed WPA2/WPA3 mode, choose WPA in this site's generator.
3. Keep business computers, point-of-sale systems and cameras on the main network, not the guest one.
4. Change default passwords and keep the access point software patched and up to date, as CISA advises.
5. Build and test the code from the guest network's name and password, not the main one.

If you run a truly open network with no password, set the security to nopass. The Wi-Fi Alliance notes that traditional open networks have no protections at all, so use one only if you understand that trade-off. This is general information, not professional security advice.

Printing and placing the sign

A Wi-Fi code is a QR code like any other, so the print rules in the QR code size and error correction guide apply: keep the blank margin around the code, print dark on light, and leave modules large enough to scan from where people stand.

The Nielsen Norman Group suggests a minimum of about 2 by 2 cm, adding about 1 cm of width for each 10 cm of scanning distance. Put the network name and password in readable type next to the code. That helps guests whose phones can't scan it, and it saves you from a support call when a camera misbehaves.

Tell people what the code does with a short label such as "Scan to join guest Wi-Fi."

When the password changes

The Wi-Fi details live inside the printed pattern, so a new password means a new code. Nothing redirects or updates it later, which is the difference explained in Do QR Codes Expire?. The old sign keeps joining guests to the old password, and then fails.

Treat the sign as part of your password routine. Keep the settings you used, regenerate the code when you rotate the password, and replace every printed copy. If you share the code in many places, keep a list of where each copy hangs.

Next step

Open the QR code generator, choose the Wi-Fi option, and enter your guest network's name, security type and password. Download the code, print a test copy, and scan it with an iPhone and an Android phone before you put it on the wall. For a broader comparison with other codes, see QR Code vs. Barcode.