Exhibit 23.1 INDEPENDENT AUDITORS' REPORT We consent to the incorporation by reference in this Registration Statement on Form S-8 of our report dated March 24, 2000, which is part of the Annual Report on Form 10-K of eSpeed, Inc., for the period ended December 31, 1999. /s/DELOITTE & TOUCHE LLP New York, New York April 6, 2000