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QR Code Guide & Safety Tips

Last updated: October 18, 2026

QR (Quick Response) codes were invented in 1994 by Denso Wave to track car parts. Today they are everywhere: restaurant menus, payments, tickets, Wi-Fi sharing and business cards. This guide explains how they work and how to use them safely.

Use AH QR Scan & Generate

  1. To scan, open Scan on a secure page, allow camera access, and keep the full code in view.
  2. Read the decoded result before opening a link, especially the domain name and any redirects.
  3. To create a code, choose a link, text, Wi-Fi network, or contact card, enter its details, then download it.
  4. Scan the downloaded image with another device before printing or sharing it.

QR codes made here are static: their data is stored in the pattern, so changing a destination means making a new code. Anyone who scans a code can read its contents. Share Wi-Fi codes only with people you want to give access to that network, and do not put account passwords or other secrets in a QR code.

QR types, images and batches

On Scan, choose Scan QR from Gallery to read a screenshot or photo. On Generate, choose Text / Link, Wi-Fi, Contact or Event and enter the details you want to share.

Colors & style controls apply to both PNG and SVG downloads, including your logo. Keep good contrast and check the downloaded code before printing.

For a batch, expand Bulk QR codes from CSV. Use a header row with name,content, followed by one code per row. Put values containing commas or newlines inside double quotes. Up to 100 codes can be generated per batch and downloaded individually.

History supports search, favorites, folders and CSV export. Export includes the currently filtered results. Folders and favorites stay on this device; signing in syncs the underlying QR history.

How a QR code works

A QR code is a grid of black and white squares that encodes data. The three large squares in the corners tell the scanner where the code is and which way it is rotated. Built-in error correction can recover some damaged data, depending on the correction level and damage location. A logo or damaged corner can still make a code unreadable, so test every design.

Common QR code types

Website links (URL)

The most popular type. Scanning opens a web page — perfect for menus, product pages and portfolios.

Plain text

Stores a short message, coupon code or serial number that appears on screen when scanned.

Wi-Fi

Stores a network name, password and security type in the format WIFI:T:WPA;S:name;P:password;;. Phones join the network automatically after scanning on supported devices, usually after confirmation.

Contact card (vCard)

Stores name, phone, email and company so people can save your details with one tap.

Tips for reliable scanning

  • Keep strong contrast: dark code on a light background works best.
  • Print at least 2 × 2 cm (0.8 × 0.8 in); larger for posters scanned from far away.
  • Leave a blank margin (quiet zone) around the code.
  • Shorter content makes a simpler, easier-to-scan code — use short links when possible.
  • Always test a printed code with a couple of different phones before mass printing.

Staying safe from QR scams ("quishing")

Criminals sometimes stick fake QR codes over real ones on parking meters, posters or emails to steal logins or payments. Protect yourself:

  • Read the link shown in the scan result before opening it. AH QR Scan & Generate always shows it first.
  • Be suspicious of misspelled domains, URL shorteners, or unexpected login pages.
  • Check for stickers placed on top of an original code in public places.
  • Never enter bank or card details on a page opened from an unknown QR code.
  • Be careful with codes in unexpected emails or text messages asking you to "verify" an account.

Static vs dynamic QR codes

Static codes (like those made here) contain the data directly and never expire. Dynamic codes point to a redirect service so the destination can be changed later, but they stop working if that service shuts down or the subscription ends.

Example: publish a restaurant menu

First publish your menu at a web address customers can open without signing in. In Generate, choose Text / Link and enter that public URL. Download SVG for a print layout or PNG for a digital sign. Keep the blank border around the code when placing it beside your restaurant name; cropping the border can break scanning.

Print one sample at its final size and scan it under the lighting where customers will use it. Open the menu using mobile data to check that it is publicly accessible. Keep that same menu URL when updating the menu, or print a new code if the address changes.

Example: share a guest network

Select Wi-Fi in Generate and enter the network name exactly, including capitalization and spaces. Choose the security option matching your router and enter the guest password. Scan a downloaded sample with a phone that is not already connected. If joining fails, check the network name, security type and password before changing the QR design.

Anyone with a photo of this code can read the encoded password. Use a guest network rather than sharing your main network credentials, and replace the printed code when you change the password. Saved history and exported files may also contain that password.

Ready to try? Create a QR code or scan one now.