EXHIBIT 23.1 INDEPENDENT AUDITORS' CONSENT We consent to incorporation by reference in this Registration Statement of eSpeed, Inc. on Form S-3 relating to eSpeed, Inc. Non-Qualified Employee Stock Purchase Plan of our report dated March 24, 2000, appearing in the Annual Report on Form 10-K of eSpeed, Inc. for the period ended December 31, 1999, and to the reference to us under the heading "Experts" in the Prospectus, which is part of this Registration Statement. /s/ Deloitte & Touche LLP New York, New York December 19, 2000