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State of California Franchise Tax Board

Customer Service Number (CSN)

The Customer Service Number application is no longer available.

We now include ReadyReturn's best features in our other free online filing application, CalFile. Now that CalFile offers ReadyReturn features and more, we no longer offer ReadyReturn, and a CSN is no longer needed.

CalFile is a simple, easy-to-use service that offers free, direct to government e-filing of your tax return. CalFile offers convenient features such as:

  • Import information to your tax return that Franchise Tax Board already has on record (similar to ReadyReturn).
  • Save a partially completed tax return to finish later.
  • Save our completed tax return to view and print later.
  • File a prior year tax return.

Get started with CalFile
Chat with an FTB Representative