You’re pouring budget into campaigns but still missing your ideal users. Acquisition rates are slow, your cost per acquisition keeps rising, and you can’t figure out why your ads aren’t landing at the right time. Every dollar spent without precise targeting cuts into your Return on Investment (ROI), and handling deals with different stakeholders leaves you with stale audience data and little insight into who’s actually installing your app.
Most of today’s digital engagement happens inside mobile apps, where people spend the majority of their screen time. That makes in-app placements a prime channel for performance-driven advertising. However, even the best creative and messaging can miss its mark without a way to bid and optimize against individual user profiles in real time.
Understanding how real-time bidding (RTB) fits into this space helps you align with user acquisition goals, drive down Effective Cost Per Install (eCPI), improve Lifetime Value (LTV), and optimize ROAS at scale.
In this blog, you’ll learn what RTB is and why it matters for app user acquisition. We’ll walk you through how RTB auctions work and how they fit into your marketing toolkit. So let’s get started!
What is Real-Time Bidding (RTB) & Why Does It Matter for UA?
Real-Time Bidding (RTB) is an automated process in programmatic advertising that enables you to bid on individual ad impressions through a Demand-Side Platform (DSP) in real-time auctions. When a user accesses a website or app, an ad request is generated and sent to an ad exchange. Your DSP evaluates available inventory and submits bids on your behalf, and the highest bidder’s ad is displayed almost instantly.
Key Benefits of Using RTB for User Acquisition
Precise Targeting via DSP: By using a DSP, you can define audiences based on demographics, behaviour, and contextual signals, ensuring ads reach users most likely to install and engage with your app.
Efficient Ad Spend: Your DSP’s algorithms bid only on impressions that match your predefined criteria, optimizing budgets and reducing costs on less relevant placements.
Broad Scalability: DSPs connect to dozens of exchanges and private marketplaces, allowing you to scale across diverse placements without manual negotiation and giving your campaigns wider reach across numerous publishers without manual negotiations.
Real-Time Optimization: Your DSP provides immediate performance feedback, allowing you to adjust bids, creatives, and audience segments on the fly for continual improvement.
Now that you understand the basics of RTB and its benefits for user acquisition, let’s examine the key components that make the RTB ecosystem work.
Understanding the components of the RTB ecosystem, including Demand-Side Platforms (DSPs), Supply-Side Platforms (SSPs), and bidding systems, is key to increasing ad revenue and keeping latency low. Below, we break down each layer with practical insights for your use:
Demand-Side Platforms (DSPs): Automating UA Bids
You use Demand-Side Platforms to acquire and optimize ad inventory programmatically in real time. A DSP ingests audience and contextual signals, dynamically adjusts bids, and serves your creatives across channels, so you can focus on scaling campaigns, not chasing inventory. Four leading DSPs in 2025 are:
ironSource DSP: Uses industry-leading machine-learning optimizers (the ROAS Optimizer and Event Optimizer) to predict and bid toward the users who’ll deliver the best long-term value. Integrates via a software development kit (SDK) you already know; its highly optimized mediation layer adds minimal round-trip overhead, making it a go-to for hyper-casual titles where every millisecond counts.
Google Display & Video 360 (DV360): offers “Maximize Conversions,” “Maximize Clicks/Installs,” and fully custom bidding strategies that draw on 40+ inventory, audience, and creative signals so you can optimize for installs, retention, or any Floodlight event you define. Floodlight is Google's conversion tracking system within the Google Marketing Platform, used to measure user actions such as purchases or sign-ups. It utilizes Floodlight activities, which are snippets of HTML and JavaScript code added to your site or app to track specific events.** DV360 prioritizes budget efficiency at scale, making it a strong choice when your goal is high-volume user acquisition rather than ultra-low overhead.
Amazon DSP: Gives you Amazon’s proprietary reach (on-Amazon and off-Amazon placements) with real-time bidding and advanced targeting, plus the ability to layer on your own bid-adjustment rules through the new Bid Adjustments feature (launched April 18, 2025). Let's you import first-party data or custom rules to boost bids in high-value moments (for example, users who’ve watched your ads), all without needing multiple line items.
AppLovin DSP: This DSP leverages AppLovin’s Axon 2 machine-learning optimizer to programmatically bid across premium in-app and CTV inventory, with advanced audience targeting, dynamic creative optimization, and real-time reporting. It integrates via SDK or server-to-server connections, offering robust support for header bidding and the proprietary MAX network. It is ideal for studios seeking holistic UA and monetization synergy.
Action for UA Teams
You should run a 30-day A/B test across these four DSPs. For each:
Set identical floor prices at $0.50, $1.00, and $1.50.
Measure win rate (auctions won ÷ auctions entered) and eCPM at each floor.
Compare performance by campaign objective: retention-sensitive (e.g., LTV-focused) vs. scale-sensitive (e.g., installs).
Use these insights to pick the DSP that aligns best with your own key performance indicator (KPI), then scale up.
Supply-Side Platforms (SSPs): Managing Inventory and Latency
SSPs help publishers manage ad inventory, set floor prices, and connect to DSPs via exchanges. Leading SSPs in 2025 include:
AppLovin MAX: AppLovin MAX’s server-to-server mediation enables real-time auctions across multiple ad networks, delivering double-digit average revenue per daily active user (ARPDAU) gains while significantly reducing auction latency.
Meta Audience Network: Meta’s Audience Network offers in-app and mobile web ad inventory powered by first- and third-party data, providing high fill rates, advanced targeting options (e.g., rewarded video, interstitial, native), and competitive eCPMs.
Unity LevelPlay: Unity LevelPlay provides a unified auction-based mediation platform integrated directly in the Unity Editor. It lets publishers serve rewarded, interstitial, banner, and native ads from all leading SDK networks with real-time analytics and optimization tools.
PubMatic: PubMatic provides Prebid.js integration for web and OpenWrap SDK for in-app environments, supporting header bidding across platforms. While specific fill rates can vary, PubMatic has reported high viewability metrics in certain campaigns.
Action for UA Teams: Integrate two SSPs using unified auction frameworks like LevelPlay or MAX. Monitor latency and auction timeout rates to ensure optimal performance.
Header Bidding vs. In-App Bidding: Which Delivers Better Results?
To get the most out of RTB, it’s essential to understand how different bidding models impact auction dynamics. Here’s how header and in-app bidding compare:
Header Bidding (Web)
Header bidding on the web extends RTB by giving all demand partners simultaneous access to your inventory before your ad server call. You add a small script in the page header that:
Sends bid requests to multiple supply-side platforms (SSPs).
Collects all bids in parallel.
Sends the highest winner to your ad server.
This flattens the traditional “first-look” hierarchy and often boosts eCPMs by up to 20 percent. As a UA manager, header bidding helps you understand the true market value for each user session and prevents undervaluing premium audiences.
In-App Bidding
In-app bidding brings the same parallel-auction model into mobile apps. Instead of ranking networks in a waterfall, an SDK-powered auction lets all demand sources bid on each ad slot simultaneously. You get:
Higher average CPMs through real-time competition.
Simplified SDK footprint, since you don’t need to integrate and update dozens of individual network SDKs.
Transparent win prices so that you can reconcile revenue without guesswork.
Action for UA Teams
Audit your RTB stack: Verify your DSPs are hooked into both header and in-app bidding auctions.
Test bid floors: Start with conservative levels and incrementally raise them to find optimal CPM thresholds.
Measure incrementally: Compare lift metrics (e.g., installs per 1,000 impressions) between waterfall and unified auctions.
Optimize budgets: Shift spend into channels where real-time bidding delivers better cost per action (CPA).
Monitor latency: Keep end-user experience smooth, aim for sub-100 ms auction times.
ROAS Analysis: Run a pre-post ROAS analysis before and after migrating from waterfall to header bidding to validate yield uplift.
Note: Waterfall mediation is the older model in which your mediation layer pings ad networks in a pre-set order based on historical eCPM tiers. If one network declines, it falls to the next. While simple, it often leaves money on the table because only top-ranked buyers ever get first dibs. In contrast, RTB-powered bidding ensures every network competes equally on every impression.
Of course, no bidding system works well without the right data. To drive smarter decisions during these auctions, let’s look at the targeting data signals and strategies that can boost your bidding precision.
To drive precise bids within your RTB setup, you need to fine-tune these data signals and targeting strategies:
User-Level Data
You feed your DSP (demand-side platform) with:
Device IDs (Identifier for Advertisers (IDFA)/Google Advertising ID (GAID)) to recognize returning users and prevent bid overlap.
First-party data from your own studios or SDK to boost bid confidence.
Hashed user cohorts for lookalike targeting, grouping similar players without exposing personal details.
Contextual Signals
You enrich each bid with real-time game data to reach high-value prospects:
Game genre (puzzle, RPG, hyper-casual) to match ad creative to player interests.
Level frequency or session length to bid more aggressively on heavy spenders.
Geo-location and time of day to align offers with local peak play times.
Privacy & Compliance
Since iOS 14, access to user-level signals has been heavily restricted, making privacy-first approaches essential for effective bidding. Instead of relying on granular identifiers, focus on:
Aggregated privacy models that replace device-level feeds with grouped data.
SKAdNetwork for install and conversion postbacks without personal IDs.
Privacy Cloud (e.g., AppsFlyer Privacy Cloud) is used for secure data, clean rooms, differential privacy, and aggregated conversion modeling.
These methods help maintain performance while aligning with platform policies, ensuring that your bidding remains precise and compliant without compromising user privacy.
Once you understand how to fine-tune these data signals and targeting strategies, the next step is to implement this knowledge. Here’s a step-by-step guide to setting up an effective RTB campaign.
How to Set Up a Mobile RTB Campaign Step-by-Step
To launch an effective real-time bidding campaign, follow these core steps that ensure both precision and scalability:
1. Select DSP & SSP Partners
You choose a demand-side platform (DSP) such as AppLovin ALX, IronSource, or Unity Ads to access auctions across premium supply-side platforms (SSPs) and ad exchanges. These DSPs integrate directly with top SSPs, ensuring you get in-app placements in relevant titles and genres via RTB protocols.
Compare each DSP’s win rate and average floor CPM across your target geos. If win rates on AppLovin ALX fall below 10% at your max CPM, lower your bid or shift budget to DSPs like Unity Ads with higher fill rates. Regularly review SSP floor price trends and negotiate floor adjustments when you see sustained low-quality impressions.
2. Define KPIs & Budgets
Because RTB means bidding happens in real time on each impression, you must set clear UA metrics:
Target CPM: Cap your maximum cost per thousand impressions to hit efficiency goals without overspending.
Daily Budget: Assign a spending limit that aligns with your overall UA plan so you know exactly how much you’ll invest each day.
Frequency Cap: controls how often each user sees your ad to prevent ad fatigue and wasted impressions.
This structured approach ensures your RTB bids stay within the defined thresholds, keeping campaigns predictable and scalable.
3. Integrate Tracking & Attribution
To effectively monitor and optimize your RTB campaigns, integrate a Mobile Measurement Partner (MMP) SDK, such as Adjust or AppsFlyer. These SDKs collect data on installs and in-app events (like purchases or level completions) and present them in dashboards that update at regular intervals.
For instance, AppsFlyer's dashboards typically update with a latency of about 10 minutes, meaning there's a short delay between an event occurring and being visible in the dashboard. Similarly, Adjust's data processing introduces a slight delay, so immediate, on-the-spot reporting isn't possible.
This latency is due to the time required for data collection, processing, and synchronization across systems. While you can access near-real-time data to inform your user acquisition strategies, always account for this brief delay when analyzing performance metrics.
4. Creative & Format Selection
In RTB auctions, your creative is your bid’s “face.” Prioritize:
Playable Ads: let users try a snippet of gameplay in-ad, boosting engagement and install intent.
Rewarded Video: offers rewards for watching and driving high-quality installs.
Interstitials: run full-screen ads at natural breaks (e.g., level end) to maximize visibility.
Run A/B tests on each format, swapping calls-to-action, video length, and playable layouts within your DSP to learn what drives the best install rate and post-install value. Then, leverage dynamic creative optimization (DCO) to automatically tailor ad elements (images, text, offers) to each user profile in real time.
By following these steps, selecting the right partners, defining UA-focused KPIs, integrating accurate (albeit slightly delayed) tracking, and optimizing formats and creatives, you build a campaign framework that balances real-time bidding efficiency with the control and insights needed to meet your ROAS goals and sustainably grow your player base.
The main point from our examination of real-time bidding (RTB) is that automation, data-driven insights, and accurate targeting are now essential for achieving efficient user acquisition. Using Demand-Side Platforms (DSPs) and Supply-Side Platforms (SSPs) allows your team to bid on the right ad impressions at the right price. Header bidding and in-app bidding frameworks help create strong competition and reduce delays.
Success depends on carefully adjusting data signals, such as device IDs, first-party audience groups, and contextual details like session length and location, and on regularly testing bid floors, creatives, and ad formats to find what brings the most installs and long-term value.
1. What’s the difference between Real-Time Bidding (RTB) and Programmatic Direct (including Private Marketplaces)?
RTB operates through an open-auction model, bidding on every impression in real time. In contrast, Programmatic Direct (and its subset Private Marketplaces, or PMPs) uses negotiated, fixed-price deals outside of the open auction. In PMPs, publishers offer premium inventory to a select group of buyers at pre-agreed CPMs, giving advertisers a first look without the competitive bid dynamics of RTB.
2. How does ad fraud impact RTB campaigns, and how can it be mitigated?
Ad fraud, where bots or malicious actors generate fake impressions or clicks, can siphon off a significant portion of your RTB budget (projected to drain over $170 billion from digital ad spending by 2028 if unchecked). To combat this, integrate fraud-detection tools (e.g., SDK-level validation, traffic-source vetting), enforce bid-request filtering with blocklists, and work with vendors who provide pre-bid verification and post-bid auditing.
3. How is Connected TV (CTV) integrating with RTB, and why does it matter?
By enabling per-impression bidding on CTV inventory, you can target lean-back audiences with the same precision as mobile or desktop RTB, unlocking high-engagement premium video environments programmatically
4. How is Real-Time Bidding different from traditional programmatic advertising? While all RTB is programmatic, not all programmatic advertising involves RTB; RTB involves open auctions for each impression, whereas other methods like programmatic direct involve pre-negotiated deals without auctions.
5. Are there any challenges associated with Real-Time Bidding?
Yes, challenges include potential ad fraud, brand safety concerns, and privacy issues due to using user data for targeting; however, advanced platforms implement measures to mitigate these risks.
