Mo. Rev. Stat. § 327.381

The board may license, in its discretion, any architect, professional engineer, professional land surveyor, or professional landscape architect licensed in another state or territory of the United States, province of Canada, or in another country, when such applicant has qualifications which are at least equivalent to the requirements for licensure as an architect, professional engineer, professional land surveyor, or professional landscape architect in this state, and provided further that the board may establish by rule the conditions under which it shall require any such applicant to take any examination it considers necessary, and provided further that any such application is accompanied by the required fee.