1. A computer system including instructions stored on a non-transitory computer-readable medium and executable by at least one processor, the computer system comprising: an extension schema validator that is executable within an extension process of an extension of a browser application, the extension schema validator configured to cause the at least one processor to validate the extension with respect to an extension application program interface (API) that is provided in conjunction with the browser application for implementation of the extension; a browser schema validator executable within a browser process of the browser application, the browser schema validator configured to cause the at least one processor to validate the extension with respect to the extension API, wherein successful validation of the extension by the extension schema validator prior to attempting validation of the extension by the browser schema validator is required, the successful validation including a determination that the extension is ready for execution with respect to the browser application, wherein the successful validation of the extension by the extension schema validator includes detection of an exception followed by a determination of resolution of the exception, prior to the determination that successful validation has occurred, wherein the validation by the browser schema validator includes repeating a previously-successful portion of the successful validation by the extension schema validator, and determining an invalidity in the previously-successful portion, wherein the invalidity determined to exist by the browser schema validator includes the exception, and wherein the browser schema validator is configured to cause the at least one processor to determine potential malicious development of the extension, based on the invalidity.