Debugging information for content rendered for display on a client device can be included in one or more watermarks inserted into the content. Performance, state, configuration, debugging, and other information can be encoded into a watermark and placed in rendered content in such a way that the information is imperceptible to most users. When a user reports a potential issue or problem, the user (or another source) can provide a version of the image frame corresponding to the issue, which enables the watermark to be located and the data extracted. A checksum or other value can be used to ensure that a complete and valid watermark was obtained. The data extracted from the watermark can then be used to attempt to identify and/or diagnose the potential issue without having to have access to the client device or communication with the user.