QR Code Generator Mistakes — WiFi & vCard Codes Done Right

Avoid the most common QR code generation mistakes and learn how to build working WiFi QR codes and vCard (business card) QR codes online, with error correction and testing tips.

A QR code that "looks right" but doesn't scan is one of the most frustrating things to debug — especially after you've already printed it on a poster, a menu, or a stack of business cards. Most of these failures come from a handful of repeatable mistakes: wrong data format, wrong error correction level, or colors that kill contrast. This guide walks through the common pitfalls and shows exactly how to build a working WiFi QR code and a vCard (digital business card) QR code.

Why some QR codes just don't scan#

A QR code isn't a picture of text — it's a structured payload that scanners parse using specific prefixes (WIFI:, BEGIN:VCARD, mailto:, tel:, etc.). If you type free-form text into a generic generator instead of the exact format a phone's camera expects, the code will scan as plain text instead of triggering the WiFi-join dialog or the "add contact" prompt. That's the single biggest cause of "it scans but nothing happens."

The other common causes:

Building a WiFi QR code that actually connects#

Modern phones (iOS 11+, most Android) recognize a specific text format when scanning a QR code with the camera app:

WIFI:T:WPA;S:MyNetworkName;P:MyPassword;H:false;;

Breaking that down:

• T — encryption type: WPA (covers WPA/WPA2/WPA3), WEP, or nopass for open networks
• S — the network SSID (name)
• P — the password (leave empty for open networks)
• H — whether the network is hidden (true/false)

If you hand-type this string, it's easy to get the field order or the trailing double-semicolon wrong, and any semicolon inside your SSID or password will break parsing unless it's escaped with a backslash. That's why it's safer to use a form-based generator that builds this string for you rather than typing it manually.

Step by step

1. Open the QR code tool and switch to the WiFi template.
2. Fill in WiFi名称 (SSID), WiFi密码 (password), and pick the 加密方式 (encryption — WPA, WEP, or nopass).
3. If the network is hidden, set 隐藏网络 to true.
4. Set 纠错级别 (error correction) to at least Q if this code will be printed and handled a lot (a WiFi sign taped to a wall gets touched, sun-faded, and creased).
5. Click 下载PNG or 下载SVG to export, or 复制图片 to paste it directly into a document.

Test before you print. Scan the code with two or three different phones (iOS and Android both, if possible) — camera apps vary slightly in how strictly they parse the WiFi payload.

Building a vCard QR code for a digital business card#

A vCard QR code encodes a contact card — when scanned, the phone offers to save the person directly to Contacts, instead of opening a link. The format is the standard vCard text block:

BEGIN:VCARD
VERSION:3.0
FN:Jane Doe
ORG:Acme Inc.
TEL:+1234567890
EMAIL:jane@acme.com
URL:https://acme.com
ADR:;;123 Main St;;;;
NOTE:Sales lead
END:VCARD

Same problem as WiFi codes: any typo in the BEGIN:VCARD/END:VCARD wrapper, or missing a colon after a field name, and the scanner just reads it as text.

Step by step

1. Open the QR code tool and switch to the 名片 (vCard/business card) template.
2. Fill in name, company, phone, email, website, address, and an optional note — only the fields you fill in are included, so leave the rest blank rather than guessing at empty-field syntax.
3. Pick a higher 纠错级别 (Q or H) if the code will sit next to a logo or be printed small on a physical business card — higher error correction lets a QR code stay scannable even with part of it obscured or damaged.
4. Export as PNG for print, or SVG if you need it to scale cleanly on a large banner.

If you're designing a physical business card layout (not just the QR code), pudone!'s business card designer lets you lay out both sides, add your own logo, and export print-ready PNG/PDF — you'd drop the vCard QR code in as one element on the card.

Choosing the right error correction level#

QR codes have four error correction levels, each trading code density for damage tolerance:

Higher error correction makes the QR pattern denser (more modules), which means the code needs to be printed slightly larger to stay scannable — there's a real tradeoff, not a reason to always pick H.

Common QR code questions#

Why does my QR code scan but open the wrong thing?

The payload was built with the wrong format. A WiFi code that opens a browser instead of the WiFi-join prompt usually means the text is missing the WIFI: prefix or has malformed fields — the phone falls back to treating it as plain text or a URL.

Can I put a logo in the middle of a QR code?

Yes, as long as you use a high error correction level (Q or H) — the logo covers part of the code's data, and the error correction bits reconstruct what's hidden. Covering too much of the code (more than roughly 25-30%) will still break scanning regardless of error correction level.

Do WiFi QR codes expose my password?

The password is stored in plain text inside the QR code's data — anyone who scans it can, in principle, extract the password (not just join the network). Treat a printed WiFi QR code the same way you'd treat writing the password on a sticky note: fine for a home or a cafe, not something to post publicly for a sensitive network.

Why is my downloaded QR code image blurry when I scale it up?

You downloaded a PNG. PNG is a fixed-resolution raster format, so scaling it up beyond its original size blurs it. Download the SVG version instead — it's vector-based and scales to any size (a large event banner, for instance) without quality loss.

Does the color of my QR code matter?

Yes — scanners need strong contrast between the foreground (dark) and background (light) colors to lock onto the position markers. Stick to dark-on-light combinations; avoid similar tones like orange-on-yellow, and never use a foreground lighter than the background.

My QR code works on some phones but not others — why?

This is almost always either a contrast/print-size issue, or a payload format issue that only strict parsers reject. Regenerate the code with a template-based tool (rather than hand-typed text) to rule out format errors, bump the error correction level, and re-test at the actual print size you'll use.

Summary#

Most "broken" QR codes aren't actually broken — they're using the wrong text format, too little error correction for how they'll be handled, or colors/size that a camera can't resolve. Using a template that builds the correct WIFI: or VCARD payload for you, picking Q/H error correction for anything printed, and testing on a couple of real phones before you print will catch nearly every failure case.