The growth is exponential - each backslash becomes two in the next iteration. Thus after n iterations we have 2^n - 1 backslashes, and we only need 30 iteration

The growth is exponential - each backslash becomes two in the next iteration. Thus after n iterations we have 2^n - 1 backslashes, and we only need 30 iterations to hit a gigabyte (and that's assuming only one quotation mark in the original JSON).