Skip to main content

​
What are Backfill Ads?

Backfill ads automatically connect multiple ad sources to fill ad inventory when there are no direct deal reservations. You can secure both the high profitability of direct deals and the stability of network ads.

Maximize Revenue with Backfill Ads

Learn more about how backfill ads work and monetization strategies.

​
Authorized Digital Sellers

Authorized Digital Sellers is an IAB standard to prevent ad inventory fraud. Through ads.txt for websites and app-ads.txt for apps, you prove to advertisers that “this inventory can be sold through Adrop.” If files are not properly configured, advertisers (DSPs) won’t trust ad requests, which may result in ads not being displayed or significantly reduced revenue.

​
Choose the Right File for Your Environment

The file you need to configure depends on where ads are rendered.

app-ads.txt

Native AppsWhen ads are displayed in Android/iOS native UI

ads.txt

WebView-based Apps / WebsitesWhen ads are displayed in WebView or browser
Even for mobile apps, if the app is built with WebView and ads are displayed in the WebView area, you need to configure ads.txt. The criterion is not whether the app is registered in the app store, but where ads are actually rendered.

​
Configuration

​
Setting Up for the First Time

If you don’t have an existing app-ads.txt, setting up a redirect is the simplest option.
Redirect 301 /app-ads.txt https://adrop.io/app-ads.txt

​
Already Using app-ads.txt

If you already have content from other ad networks, you cannot use a redirect. Visit the URL below, copy the content, and add it to your existing file.
https://adrop.io/app-ads.txt
Deleting existing content will break other ad networks. Make sure to keep existing content and append Adrop’s content.

​
Upload Location

Upload to the root path of the website domain registered in App Store/Play Store.
https://your-domain.com/app-ads.txt

​
Verification

​
File Access Check

Visit the configured URL to verify the file is properly applied. 
https://your-domain.com/ads.txt
https://your-domain.com/app-ads.txt

​
robots.txt Crawling Permission

If robots.txt blocks crawlers from accessing ads.txt or app-ads.txt, ad networks cannot verify the files and ads will not be served. Ensure your robots.txt allows crawling of these paths:
robots.txt
User-agent: *
Allow: /ads.txt
Allow: /app-ads.txt

​
Verify Google Crawler Access

Even if the file appears correctly in your browser, ads won’t serve if your server or CDN blocks Googlebot. Verify with the following commands: 
# 1. Check file accessibility
curl -iL https://your-domain.com/ads.txt

# 2. Check accessibility as Google crawler
curl -iL -A "Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)" https://your-domain.com/ads.txt
Both commands should return identical content. If the second command returns a different response, check your server/CDN configuration.
Proper txt file configuration for your environment is required for backfill ads to serve correctly. Without this setup or if crawling is blocked, ad requests may be rejected.

​
Next Steps

Android

Android backfill ads setup

iOS

iOS backfill ads setup

Flutter

Flutter backfill ads setup

React Native

React Native backfill ads setup

Web

Web backfill ads setup