DOCUMENTATION
What CKey is.
CKey is an open optical code: a printable symbol that carries bytes, like a QR code, with an open specification, a C++20 reference core, and SDKs for Swift, the web, Android, and .NET.
Docs: Overview · Payloads · SDKs · Telemetry · API
Experimental. CKey is a pre-1.0 research project. Formats can still change between builds, decoding is tested on rendered and simulated camera frames but not yet on a labelled real-camera corpus, and no phone camera app recognises CKey on its own. Do not rely on a CKey as the only way to reach something important.
How to scan a CKey
Ordinary camera apps do not read CKey yet. To scan one you need software built with the CKey core:
- CKey Reader, the reference reader apps in the CKey repository (iOS and macOS), built from source.
- An app that embeds a CKey SDK. Every SDK includes a scanner that finds the border, refines it for each profile, and decodes. See the SDK quick starts.
A conforming reader shows the decoded payload and, for recognised forms such as https: links, offers an action that you must tap. It never opens a link by itself. The rules are on the payload conventions page.
Profiles
A profile is a symbol family with its own geometry and capacity. Readers try Profile 0 first, then Profiles 1, 2, and 3.
| PROFILE | CAPACITY | USE |
|---|---|---|
| 0 | 31 versions, 27 to 4,619 bytes at level M | The general-purpose code. Picks the smallest version that fits; error correction L, M, Q, or H. |
| 0.1 | as Profile 0 | The print layout of Profile 0, for printed material. |
| 1 | exactly 16 bytes | A compact locator, not a text carrier. |
| 2 | up to 200 bytes | Experimental text profile. |
| 3 | up to 2,048 bytes | Experimental extended profile with seven capacity tiers. |
The renderer on this site makes Profile 0 and 0.1 symbols. The formats are specified in the spec directory of the repository.
What openckey.org adds
This website hosts two kinds of destination for a CKey: hosted text and short query links. It also offers the in-browser renderer, the package downloads, and the endpoint that receives optional aggregate SDK telemetry. The API reference lists every endpoint.
Licences
CKey itself — specification, core, and SDKs — is open source under the MIT licence. The openckey.org website and its service code are proprietary and are not covered by that licence.