iminuit is designed from ground up to be fast, interactive and cython friendly. iminuit extract function signature very permissively starting from checking func_code down to last resort of parsing docstring (or you could tell iminuit to stop looking and take your answer). The interface is inspired heavily by PyMinuit and the status printout is inspired by ROOT Minuit. iminuit is mostly compatible with PyMinuit (with few exceptions). Existing PyMinuit code can be ported to iminuit by just changing the import statement.