Investor Overview

NYSE: CSLT

June 2017

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Safe HarborStatement

This presentation contains forward-looking statements regarding ourtrends, our strategies and the anticipated performance of our business,including our guidance for the full year of 2017. These statements, otherthan references to our prior guidance, are made as of today, and reflectmanagement’s current views and expectations, and are subject to variousrisks, uncertainties and assumptions. If this presentation is viewed aftertoday, the information in the presentation may no longer be current oraccurate. We disclaim any obligation to update or revise any forward-looking statements.

Please refer to the Company’s first quarter 2017 financial results pressrelease dated April 26, 2017, and the risk factors included in thecompany’s filings with the Securities and Exchange Commission fordiscussion of important factors that may cause actual events or results todiffer materially from those contained in our forward-looking statements.

The guidance provided in this presentation was made on April 26, 2017and speaks only as of that date. The Company does not update itsguidance intra-quarter through investor presentations such as this. If thecompany updates its guidance beyond what was provided on April 26, itwill do so only in a public forum. In addition, please note the close date ofthe Jiff acquisition was April 3rd. Accordingly, the deferred revenue fairvalue adjustment discussed in this presentation is a preliminary estimateand is subject to change upon the completion of purchase priceaccounting.

This presentation also includes certain non-GAAP metrics, such as non-GAAP gross margin, pro forma revenue, operating expenses, andoperating loss, that we believe aid in the understanding of our financialresults and future expectations. A reconciliation to comparable GAAPmetrics, on a historical basis, can be found in the appendix section of thispresentation. These non-GAAP financial measures should be consideredin addition to, not as a substitute for or in isolation from, measuresprepared in accordance with GAAP.

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Castlight is a health benefits platform that engages employees to make better health decisions and enables benefit leaders to

communicate and measure their programs

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Investment Highlights

LARGE MARKET OPPORTUNITY WITH

“CONSUMERISM” TAILWINDS

MOST COMPREHENSIVE HEALTH BENEFITS

PLATFORM

HIGH GROWTH SAAS BUSINESS MODEL

BLUE CHIP CUSTOMER BASE – 70+ F500

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Health Benefits Today: low engagement & poor health decisions

73% of employees don’t fully understand their health benefits

Program utilization is typically lower than 10%

Employees pay up to 10X more for the same service

Up to 20% of surgeries are unnecessary

5-6% increase in health spending each year for employers

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Why aren’t employees engaged?

Explosion of vendors

Soaring consumer expectations

Convoluted healthcare system

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All-in-one wellbeing

Deep partner integrations

Motivating user experience

1

2

3

Comprehensive decision support

Data-driven personalization

Multi-channel outreach

1

2

3

Health

Benefits

Platform

For employees

Improve every aspect of their health experience: from staying healthy,

to accessing care, to managing a condition

For employers

More efficient than ever before to engage with employees, purchase

and deploy a wide range of benefit technologies, and measure impact

The Solution: One End-to-End Platform

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The Castlight Health Benefits Platform

Integrate Engage Evaluate

Personalized content and timely outreach

and to GUIDEemployees to better

decisions

Simple, integrated way to help UNDERSTAND &

ACCESS benefits

Real-time INSIGHT into engagement with

benefits and programs

One end-to-end platform

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Integrate

Across medical, pharmacy, dental, behavioral

health and third party programs

Picking a doctor

Deciding where to get urgent care

Getting the most out a benefits plan

Learning how to manage a chronic condition

Example Decision AreasCost

Personalized cost

estimates for the

employee based on their

specific plan design,

network, and amount

spent to date

Education Content

Consumer-oriented content, written by

expert clinicians, that supports

procedures, conditions, vaccines, labs,

imaging, and more

Quality

17 nationally endorsed

sources of clinical

quality for hospitals and

physicians, including

condition and procedure

specific information

Tracking finances (e.g. HSA spend, claims)

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Engage

Personalized employee experience based on their health journey

Predict Health

Risk

Claims, demographics, and

employee activity data drive

identification of employee

health status and potential

future health conditions

Recommend Best

Options

Individualized presentation

of services and programs

drives the employee to the

right care and program at

the right time

Multi-Channel

Outreach

Proactive connection with

employees where they are,

via the channels most

applicable to them

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Evaluate

Back Pain Diabetes Adult Preventative

Care

Start PTor chiropractic care Take a glucose test

Complete a preventive service

Individuals with lower back pain

(who aren’t using PT or chiropractic care)

Individuals with or at risk for diabetes

(who have not hada glucose test)

Adults who have not had a preventive

service within one year

About the

Campaign

Campaign

Recommendation

Impact on

Preventive

Services

2.7xincrease

1.8xincrease

1.7xincrease

Note: Early results from claims-based analysis aggregated from customers that have been deployed on Castlight Action for over 6 months

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The Jiff Wellbeing Platform

Central hub for wellbeing that drives employee

engagement

App store approach integrates with over 50+

solutions that sync seamlessly

Mobile-first technology with a world-class user

experience

Rewards Layer: Personalized incentives drive

desired micro-behaviors

Model: PEPM-based subscription and service

fees, contract terms typically three-years paid

monthly, quarterly or annually

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Jiff’s Ecosystem & Deep Partner Integrations

Incentivize specific

targeted behavior deep

within third party

solutions

Collect ‘digital exhaust’

on users for

personalization and

reporting

ScalableIntegration Framework

Bi-directional flow of data

Purchase a wide range

of solutions directly thru

Jiff

ResellerContracts

Activity Tracking

Food Tracking

Sleep Tracking

Fitness Tracking

Biometrics

HRA

Health Coaching

Nutritional Coaching

Resilience

Smoking Cessation

Fertility / Pregnancy

Parenting

Cardiovascular

Health

Financial Health

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Castlight-Jiff Joint Value Proposition

Simplify navigation for all benefit resources, globally

Improve Health Access Care Manage a Condition

Interact with employees throughout the year

Target most expensive conditions and employees

Increase employee happiness while decreasing risk

Improve efficiency of the health care system and quality of care

Lower costs for most expensive population

Real time intercept when your employee is about to become a patient

Financial Update

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Financial Highlights

STRONG GROWTHHEALTHY MARGIN

PROFILE

SCALING BUSINESS

$107M IN LTM REVENUE

74% 1Q 2017 GROSS MARGINS

REDUCTION IN Y/Y OPERATING LOSSES

$82$107

1Q'16 1Q'17

30% Growth

63%

74%

1Q '16 1Q'17

-$13.0

-$5.5

1Q'16 1Q'17

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Cash Balance

Cash as of 03/31/17Q1 2017 Cash

Flow from Operations

$103.2 M $(10.9) M*

Castlight expects to reach cash flow breakeven by the end

of 2018 with at least $60 million of cash

* Includes $4.0 million in Jiff-related transaction costs

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FY 2017 Guidance*

2017 Guidance & Key Initiatives

FY 2017 outlook includes Jiff starting in 2Q

* Guidance as of 04/26/17. Non-GAAP operating expenses exclude

in the impact of stock-based compensation, litigation settlements,

workforce reduction expenses, capitalization and amortization of

internal-use software, and acquisition related costs.

2017 Key Initiatives

Drive faster platform

adoption by new

customers

Drive customer stickiness

Integrate Castlight &

Jiff to unlock the

strategic value of

combined company

GAAP Revenue $132mm to $136mm

Non-GAAP Operating

Income (Loss)

$(35)mm to $(31)mm

Non-GAAP EPS $(0.28) to $(0.24)

Basic & Diluted Avg.

Wgt. Shares O/S

125mm to 127mm

Investor Overview

NYSE: CSLT

June 2017

Appendix

June 2017

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Castlight’s Business Model & Go-To-Market

Business Model

• Platform sold on a price per employee per month (PEPM) basis

• Typically three-year contracts

• Long-term gross margin target range of 70%-75%

Target Customers

• Targets US self-insured employers

• Platform purchased by health benefits manager/HR

• 240 customers, including 70+ Fortune 500

Go-To-Market

• Direct sales team/channel partner approach

• Strategic relationships with Anthem and SAP

• Expanding relationships with health benefits consultants

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Gross Profit: Reconciliation of GAAP to Non-GAAP

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Operating Expense: Reconciliation of GAAP to Non-GAAP

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Reconciliation of GAAP to non-GAAP Revenue

Annual Guidance

2017

GAAP revenue guidance $132-136

Add back:

Deferred revenue fair value adjustment (1) 1.9

Jiff revenue Q1’17 (2) 3.7

Non-GAAP pro forma revenue guidance (3) $138-142

(1) The close date of the Jiff acquisition occurred on April 3, 2017, subsequent to our fiscal quarter end. Accordingly, the deferred revenue fair value

adjustment is a preliminary estimate and is subject to change upon the completion of purchase accounting. The impact on revenue related to purchase

accounting as a result of these transactions limits the comparability of revenue between periods. While the deferred revenue written down in connection

with Castlight’s acquisition of Jiff will never be recognized as revenue under GAAP, we do not expect the acquisition to have an impact on future renewal

rates of the contracts included within the deferred revenue write-down, nor do we expect revenue generated from new service and subscription contracts

to be similarly impacted by purchase accounting adjustments. If this adjustment was not made, Castlight’s future revenue growth rates could appear

overstated.

(2) Non-GAAP pro forma revenue guidance combines the results of Jiff and Castlight as if Jiff was acquired at the beginning of our fiscal year 2017 and,

therefore, includes Jiff’s first quarter 2017 revenue as conformed to Castlight accounting policy.

(3) We believe presenting non-GAAP pro forma revenue guidance to include the impact of Jiff’s first quarter revenue as if the transaction had been

completed at the beginning of our fiscal year 2017, and excluding the impact of deferred revenue write-down, will aid in the comparability between periods

and in assessing our overall operating performance. We have performed an initial review of Jiff’s accounting policies, upon comprehensive review, we

may identify other differences among the accounting policies of Castlight and Jiff that, when conformed, could have an impact on future revenue. Non-

GAAP pro forma revenue has limitations as an analytical tool, and you should not consider it in isolation or as a substitute for GAAP revenue. Other

companies in our industry may calculate this measure differently, which may limit its usefulness as a comparative measure.

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Explanation of Non-GAAP Financial Measures

Deferred revenue fair value adjustment: In connection with the acquisition of Jiff, the deferred revenue balances from Jiff

products were required to be written down due to purchase accounting in accordance with GAAP. While the deferred revenue

written down in connection with the acquisitions will never be recognized as revenues under GAAP, we do not expect the

acquisition of Jiff to have an impact on future renewal rates of the contracts included within the deferred revenue write-down, nor

do we expect revenues generated from new service and subscription contracts to be similarly impacted by purchase accounting

adjustments.

Jiff revenue Q1’17: An adjustment to Jiff’s revenue to adhere to Castlight’s accounting policies, in connection with the acquisition

of Jiff.

Stock-based compensation: A non-cash expense arising from the grant of stock-based awards to employees.

Litigation settlement: Represents settlements of lawsuits related to Castlight’s initial public offering and the acquisition of Jiff in

the first quarter of 2016 and 2017, respectively.

Reduction in workforce: Expenses associated with the program Castlight undertook in the second quarter of 2016 to reduce the

Company's workforce by fourteen percent.

Capitalization and amortization of internal-use software: Development costs incurred during the application development stage of

our cloud-based service that we capitalize. Capitalized software development costs are included as part of property, plant and

equipment and are amortized on a straight-line basis over the technology's estimated useful life.

Acquisition related costs: Transaction and integration costs associated with the Jiff acquisition. These costs include all

incremental expenses incurred to effect a business combination. Acquisition costs include advisory, legal, accounting, valuation,

and other professional or consulting fees. Integration costs include expenses directly related to integration of business and facility

operations, information technology systems and infrastructure and other employee related costs.