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                                                                     EXHIBIT 5.1



                                  July 30, 2001


8x8, Inc.
2445 Mission College Blvd.
Santa Clara, CA  95054

        RE:  REGISTRATION STATEMENT ON FORM S-8

Ladies and Gentlemen:

        We have examined the Registration Statement on Form S-8 to be filed by
you with the Securities and Exchange Commission on or about July 30, 2001 (the
"Registration Statement"), in connection with the registration under the
Securities Act of 1933, as amended, of (i) 1,149,984 shares of your Common Stock
reserved for issuance under the 8x8, Inc. 1996 Stock Plan; (ii) 500,000 shares
of your Common Stock reserved for issuance under the 8x8, Inc. 1996 Employee
Stock Purchase Plan (collectively, the "Shares") (collectively, the "Plans"). As
legal counsel for 8x8, Inc., we have examined the proceedings taken and are
familiar with the proceedings taken or proposed to be taken by you in connection
with the sale and issuance of the Shares under the Plans.

        It is our opinion that, when issued and sold in the manner referred to
in the Plans and pursuant to the respective agreement which accompanies each
grant pursuant to the Plans, the Shares will be legally and validly issued,
fully paid and nonassessable.

        We consent to the use of this opinion as an exhibit to the Registration
Statement and further consent to the use of our name wherever appearing in the
Registration Statement and any amendments to it.


                                            Very truly yours,

                                            WILSON SONSINI GOODRICH & ROSATI
                                            Professional Corporation

                                            /s/ WILSON SONSINI GOODRICH & ROSATI