How can I generate a circular qr-code like a messenger or a kik code?

Question

How can you generate the codes like shown below:

Answer 1

I will assume you want to use an existing standard instead of attempting to invent your own encoder\decoder.

Any 2D barcode can be intentionally damaged for esthetics if you crank up the redundancy used for error correction. 2D barcodes are designed to survive a certain amount of damage. Placing an image in the center and rounding the corners are both considered damage from the perspective of the reader. For round corners you can't use a barcode with orientation dots in the corners, like QR. You must choose a format that is oriented with a marker in the middle like:

MaxiCode

https://en.wikipedia.org/wiki/MaxiCode

ShotCode

https://en.wikipedia.org/wiki/ShotCode

Aztec Code

https://en.wikipedia.org/wiki/Aztec_Code

Similarly, if you wanted to place an image in the center then you wouldn't want to use one that requires a bullseye for orientation, unless you can retain the bullseye somehow in your central image. To place an image in the center and also round the corners you need to get creative. In your first image there are four tracking dots around the image. In the second and third examples the company uses it's own logo as the orientation point.