How to safely scan a QR code for a swap deposit on a small screen

07 September 2026

First, ensure the QR code you are about to scan matches the deposit address shown on the exchange platform in plain text. Then scan only from a clean, unobstructed screen using your wallet app's built-in scanner, not a third-party camera app. These two steps prevent the most common QR-code failures on small screens: scanning a wrong code or misreading a damaged one.

Why small screens cause problems

Phone screens are smaller than monitors. A QR code rendered on a phone often has lower resolution and less contrast than one on a desktop. The exchange's site may shrink the code to fit your screen, or your brightness may be too low. If the code is blurry, your wallet might decode a different address or fail entirely.

The safe scanning procedure

1. Display the code on a static screen. Do not scan while the page is still loading or while the code is animating. Let the exchange site finish rendering.

2. Increase screen brightness to maximum. This improves contrast. A dim screen can cause misreads.

3. Hold your scanning phone steady, about 10-15 cm away. Too close, and the camera cannot focus. Too far, and the code becomes too small to resolve.

4. Use your wallet app's QR scanner, not your phone's camera app. Wallet scanners are tuned to read crypto addresses. General camera apps may decode a URL that leads to a phishing site instead of the raw address.

5. After scanning, compare the first and last six characters of the decoded address with the plain-text address on the exchange screen. Do not rely on the QR code alone. A damaged code can change one character without visibly distorting the image.

What can go wrong on a phone

• Reflection and glare. A glossy phone screen under bright light can reflect your face or a lamp into the camera. Tilt the source phone slightly away from the light.

• Partial code. If the QR code is cropped by the exchange's interface - for example, if a banner overlaps its bottom edge - the scan will fail. Scroll the page so the code is fully visible.

• Dynamic codes. Some exchange sites generate a new QR code each time you refresh. If you take a screenshot and scan it later, the code may have expired. Always scan live from the exchange page.

• Low battery mode. Some phones reduce screen resolution in low-power mode. Turn off battery saver temporarily while scanning.

When to abort

If the code fails to scan after three tries, do not keep attempting. Manually copy the plain-text address from the exchange site and paste it into your wallet. Typing a long address by hand on a small screen invites errors; use copy-paste. But be aware that clipboard hijackers can replace the copied address - this is covered on the sibling page "How clipboard hijackers steal a crypto address during a mobile swap."

After the scan

Once your wallet shows the decoded address, confirm it matches the exchange address character by character. Then proceed with the swap. Remember that a successful scan only gets the deposit address right. The next common mistake is sending tokens to the wrong network, which is explained on the hub page "Mobile wallet swap mistakes to avoid." That page ties together all the pitfalls that occur after you have scanned correctly.

A safe QR scan on a small screen is about patience and verification. Speed saves nothing if the address is wrong.

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