Skip to main content
Decoders

QR Code Decoder

Drop or choose an image, decode the first readable QR symbol with createImageBitmap, Canvas, and jsQR, classify common payload prefixes, and copy the exact text locally. Useful for developers, analysts, and anyone extracting QR data from screenshots, photos, or scanned documents without camera access.

QR tools

Drag & drop a QR code imageor click to browse — PNG, JPEG, GIF, BMP, WebP

In brief

The decoder reads one local image into Canvas, tries normal and inverted QR pixels, returns the first symbol jsQR finds, and never uploads the image.

What this tool supports

  • Accepts one image chosen through the file picker or drag-and-drop, decodes it with createImageBitmap, and reads RGBA pixels from a Canvas.
  • Uses jsQR with inversionAttempts set to attemptBoth and returns the first non-empty QR payload found in the image.
  • Classifies prefixes for http/https, mailto, tel, WIFI, vCard, SMS, geo, and VEVENT; all other payloads are labeled text.
  • Shows an image preview, copies the exact decoded string, and optionally stores the ten most recent results in localStorage when history is enabled.

How to use QR Code Decoder

Follow this implementation-specific workflow for QR Code Decoder; each step reflects the controls and limits in the current browser workspace.

  1. 1

    Step 1

    Provide the exact source

    Choose or drop a sharp image containing one complete QR symbol with its quiet zone visible.

  2. 2

    Step 2

    Choose the operation

    Use the file decoder rather than camera mode; the input control accepts browser-decodable image types.

  3. 3

    Step 3

    Configure the available options

    Wait while createImageBitmap decodes the file, Canvas obtains pixels, and jsQR tries both normal and inverted luminance.

  4. 4

    Step 4

    Run the local operation

    Review the full payload and its heuristic type label; do not open a URL until its scheme, host, path, and look-alike characters are checked.

  5. 5

    Step 5

    Verify and continue

    Copy the payload for the next local tool and clear optional history when the value is sensitive.

Common mistakes

Uploading a blurred, cropped, tiny, or perspective-distorted symbol

Consequence: Finder patterns or the required quiet zone may be unreadable, producing “No QR code was found.”

Fix: Use the original-resolution image, keep all four edges and quiet zone, and avoid screenshots compressed several times.

Trusting the type label as content validation

Consequence: Classification only checks string prefixes; a URL can still be deceptive and a WIFI/vCard payload can be malformed.

Fix: Inspect the exact decoded text and validate it with the destination-specific tool before acting.

Assuming every image type and size is bounded safely

Consequence: The picker accepts image/* but there is no explicit file-size or dimension guard before bitmap allocation.

Fix: Use a normal still-image format and downscale unusually large files before decoding on memory-constrained devices.

Best practices

  • Decode unknown QR codes as text first; never follow a link automatically.
  • Keep the original image until the decoded payload has been compared character-for-character.
  • Disable or clear local history when payloads contain Wi-Fi credentials, tokens, contact data, or private URLs.

Connected workflows

Extract and validate a QR payload from an image

QR Code DecoderURL ValidatorJWT Decoder

Decode a local image, inspect the exact untrusted string, then route it to a validator or decoder appropriate to its claimed type.

  1. Select the original QR image
  2. Decode one payload
  3. Inspect the exact text
  4. Validate the claimed type
  5. Clear sensitive history

Browser limitations

  • createImageBitmap and Canvas decoding support vary by image codec/browser; SVG, HEIC, animated, corrupted, or extremely large files may fail or exhaust memory.
  • Only the first readable QR result is returned; there is no multi-code selection, barcode support, damaged-symbol repair control, or confidence score.
  • Decoding happens synchronously over full image pixels on the main thread after bitmap creation, so large images can briefly block interaction.

Authoritative resources

ISO/IEC 18004:2024 QR code symbology specificationPublisher: ISO / IEC · Reviewed: 2026-07-26Window.createImageBitmap()Publisher: MDN Web Docs · Reviewed: 2026-07-26

Concrete examples

Input
A PNG containing one QR symbol whose encoded payload is https://example.com/docs
Result
Type: url; the exact string is available to copy.

jsQR returns the symbol data, and parseQRCodeType labels strings starting with https:// as url without fetching or validating the destination.

Frequently asked questions

Can this decoder read a QR code without camera permission?

Yes. It only needs a selected local image and never requests camera access; use QR Scanner for an explicit camera workflow.

Why does a clear-looking screenshot sometimes fail?

Cropping the quiet zone, display scaling, compression, glare, rotation/perspective, or low module contrast can prevent finder and grid recovery.

Will it decode several QR codes in one photograph?

No. The current jsQR call returns a single result and the workspace exposes only that first payload.

Does opening a decoded URL happen automatically?

No. The value is displayed first. If an Open URL control appears, it is a separate user action and the target must still be reviewed.

Where are previous decoded values kept?

Only when the global history setting is enabled, up to ten results are stored under the decoder-specific localStorage key and can be cleared.

Privacy and offline behavior

The selected image, Canvas pixels, preview data URL, and decoded payload stay on this device. Optional history is written to this browser’s localStorage only when enabled; the decoder works offline after its app code is cached.