I'm trying to pass Python data (lists, dicts, strings..., arbitrarily nested) to PyV8. class Global(object): def __init__(self, data): self.data = data ctx = PyV8.JSContext(Global([{'a':1}])) ctx.enter() res = ctx.eval('data.length') js_len = PyV8.convert(res) print js_len The code above prints None, presumably because the data object is not transformed to a JSArray and thus data.length evaluates to undefined . Is there a reliable way to do the necessary conversion in PyV8 other than using JSON? Michel Müller Apparently PyV8 doesn't correctly convert python lists to Javascript arrays, which