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                                                                     EXHIBIT 5.1



                                  July 8, 1997


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 8, 1997
(the "Registration Statement"), in connection with the registration under the
Securities Act of 1933, as amended, of (i) 1,765,364 shares of your Common Stock
reserved for issuance under the 8x8 1992 Stock Option Plan; (ii) 999,753 shares
of your Common Stock reserved for issuance under the 8x8 1996 Stock Plan; (iii)
150,000 shares of Common Stock reserved for issuance under the 8x8 1996 Director
Option Plan; and (iv) 500,000 shares of your Common Stock reserved for issuance
under the 8x8 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 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 under 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



