Consent of Independent Registered Public Accounting Firm

We consent to the incorporation by reference in the following Registration Statements:

▪ Registration Statement (Form S-4 No. 333-215861) of Castlight Health, Inc., and

▪ Registration Statements (Form S-8 Nos. 333-194566, 333-202701, 333-216374, 333-221191, and 333-223373) pertaining to employee benefit plans of Castlight Health, Inc.;

of our report dated March 1, 2019, with respect to the consolidated financial statements of Castlight Health, Inc. included in this Annual Report (Form 10-K) of Castlight Health, Inc. for the year ended December 31, 2018.

/s/ Ernst & Young LLP

San Francisco, California

March 1, 2019