What is CPI? Cost Per Install Explained

CPI (Cost Per Install) is a mobile advertising and affiliate marketing model where an advertiser pays a fixed commission each time a referred user installs and opens their mobile application. CPI is a subset of the broader CPA (Cost Per Action) model, specifically focused on app installs. It's the dominant pricing model for mobile app user acquisition and one of the most popular offer types on CPA networks like RevBoost.

Why CPI Matters

Mobile apps are the backbone of the modern digital economy. Every app — from fintech to gaming to health — needs users, and CPI is how most of them acquire those users at scale through affiliate and performance marketing channels. According to Business of Apps, global app install ad spend runs into the tens of billions of dollars annually, underscoring the scale of CPI-driven user acquisition.

For publishers, CPI offers are attractive because app installs are relatively easy conversions. The user just needs to download and open an app — no credit card required, no lengthy form to fill out, no purchase to make. This makes CPI offers convert at higher rates than more complex CPA actions, especially on mobile traffic.

For advertisers, CPI provides predictable user acquisition costs. If a fintech app pays $3.00 CPI and needs 50,000 installs to hit their quarterly goal, they know the budget: $150,000. The challenge is ensuring those installs come from real users who will actually engage with the app.

How CPI Works

1. The advertiser creates a CPI offer — They define the payout, target geos, allowed traffic types, and any post-install requirements (some offers require the user to open the app, complete onboarding, or reach a specific level).
2. The CPA network lists the offer — Publishers can browse and apply to run the offer.
3. The publisher promotes the app — Through their website, social media, offerwall, paid ads, or other channels.
4. The user clicks the tracking link — The link redirects to the app store (iOS App Store or Google Play) with tracking parameters intact.
5. The user installs and opens the app — The mobile measurement partner (MMP) or tracking SDK detects the install and attributes it to the publisher.
6. The conversion is recorded — The advertiser's system fires a postback to the CPA network, which credits the publisher.

CPI Rates by App Category

App Category	Typical CPI (iOS)	Typical CPI (Android)	Incent Allowed?
Fintech / Banking	$3.00 – $10.00	$1.50 – $6.00	Often yes
Gaming (Casual)	$1.00 – $4.00	$0.50 – $2.00	Often yes
Gaming (Mid-Core)	$3.00 – $8.00	$2.00 – $5.00	Sometimes
Health / Fitness	$2.00 – $6.00	$1.00 – $3.50	Varies
Shopping / E-Commerce	$1.50 – $5.00	$0.75 – $3.00	Sometimes
Utilities / Tools	$0.50 – $2.50	$0.30 – $1.50	Often yes
Streaming / Media	$2.00 – $7.00	$1.00 – $4.00	Varies

iOS CPIs are consistently higher than Android because iOS users tend to have higher lifetime value (they spend more within apps). US traffic commands the highest CPIs across all categories. Industry data from Insider Intelligence consistently confirms this iOS premium across all app verticals.

CPI vs. CPA vs. CPE

Model	Publisher Earns When...	Typical Payout	Conversion Difficulty
CPI	User installs and opens the app	$0.50 – $10.00	Easy-Medium
CPA (general)	User completes any defined action	$0.50 – $50+	Varies
CPE (Cost Per Engagement)	User completes a post-install action (e.g., reach level 5, make a deposit)	$5.00 – $50+	Hard

Some offers that appear as "CPI" actually have post-install requirements (CPE). Always read the offer details carefully. An offer described as "Install + Complete Tutorial" is technically CPE and will have a lower conversion rate than pure CPI.

CPI and Offerwalls

CPI offers are among the most popular on offerwalls and rewards platforms. Users on GPT sites and rewards apps are highly motivated to install free apps to earn points. This makes offerwalls one of the highest-volume sources of CPI traffic.

For offerwall operators, CPI offers are ideal because they're quick for users to complete (download, open, done), which keeps users engaged and coming back for more. A well-curated selection of CPI offers can significantly boost your platform's offer completion rate and user satisfaction.

Example: CPI Campaign Performance

Scenario: You promote a fintech app install offer on your rewards site. The offer pays $4.00 CPI for US iOS users who install and open the app.

Metric	Value
Offer clicks from your offerwall	2,000
Successful installs	500 (25% conversion rate)
CPI payout	$4.00
Total earnings	$2,000
EPC	$2,000 / 2,000 = $1.00
User rewards paid (70%)	$1,400
Your margin	$600

Tips for Running CPI Offers

• Target mobile traffic — CPI offers only work on mobile devices. Ensure your traffic source serves mobile users. Desktop clicks are wasted.
• Match the OS — iOS offers won't convert on Android devices and vice versa. Use device targeting or separate tracking links per OS.
• Check post-install requirements — Some "CPI" offers require users to complete onboarding, reach a level, or make a deposit. These are harder to convert and may need different promotion strategies.
• Monitor offer caps — Popular CPI offers can hit their daily caps quickly, especially during business hours. Track cap status and have backup offers ready.
• Use Sub IDs — Track which traffic segments produce the highest install rates and lowest scrub rates to optimize your campaigns.

Related Terms

• CPA (Cost Per Action) — The broader pricing model that CPI falls under
• Offerwall — A primary distribution channel for CPI offers
• Incentivized Traffic — Traffic type commonly used to drive app installs at scale
• EPC (Earnings Per Click) — Key performance metric for evaluating CPI offer profitability
• Postback Tracking — Required for tracking mobile app installs server-to-server