Cost Per Action (CPA)

CPI stands for Cost Per Install, meaning the cost that an advertiser pays each time a user installs their mobile app after clicking on an ad. CPI is a performance-based pricing model, which means that the advertiser only pays for results that directly contribute to their business goals, such as app installations. This pricing model is particularly popular among mobile app developers who want to promote their apps and acquire new users.

The amount spent for each newly-acquired mobile app user over a given time period. Customer Acquisition Cost (CAC) for mobile apps refers to the cost that a business incurs to acquire a new user for their mobile application over a specific period of time. In other words, it is the amount of money spent to attract a user to download and install a mobile app on their device. Whether you are just embarking on your journey or navigating quite a while to create a successful mobile app, the Customer Acquisition Cost (CAC) must be at the forefront of your mind.

Return on Ad Spend (ROAS) measures the revenue generated for every dollar spent on advertising. It is calculated by dividing total revenue attributed to a campaign by the total ad spend on that campaign. A ROAS of 2.0 means the campaign generated $2 in revenue for every $1 spent. ROAS is the most widely used profitability metric in mobile user acquisition because it directly connects marketing investment to revenue outcomes. For subscription apps, ROAS calculations must account for the time lag between ad spend and revenue realization — a user acquired today may not generate their first payment for 7 days (if they start with a free trial) and may generate revenue over months or years of subscription renewals. This makes "Day 0 ROAS" (revenue from immediate purchases) an incomplete picture. Growth teams track ROAS at multiple horizons — Day 7, Day 30, Day 90, Day 365 — to understand the full return curve. Target ROAS thresholds depend heavily on a company's margin structure: apps routing payments through app store billing (with 15–30% commissions) need higher gross ROAS than apps processing through web checkout to achieve the same profitability.

Mobile app conversion rate (CR or CVR) is the percentage of users who achieve a specific goal within the app, such as making a purchase, creating an account, subscribing to a service, or completing a survey. Conversion rates are an important metric for mobile app developers and marketers as they indicate the effectiveness of the app in driving user engagement and achieving business goals. A higher conversion rate typically means that the app is successfully guiding users towards the desired action, while a lower conversion rate may indicate that there are issues with the user experience or the app's marketing strategy.

User acquisition refers to the strategies and activities used to attract new users to a mobile app or platform. It encompasses paid advertising, organic discovery, and referral programs working together to drive installs and grow an engaged user base.