What is app-ads.txt for CTV?

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Last updated: April 8, 2026

Quick Answer: App-ads.txt for CTV is a text file standard that helps prevent ad fraud in connected TV advertising by allowing publishers to declare authorized digital sellers of their inventory. Introduced by the IAB Tech Lab in 2017, it has been widely adopted across the CTV ecosystem, with over 90% of top CTV apps implementing it by 2023. This implementation helps ensure that advertisers only purchase legitimate ad space, reducing invalid traffic and increasing transparency in programmatic CTV transactions.

Key Facts

Introduced by IAB Tech Lab in 2017
Over 90% adoption rate among top CTV apps by 2023
Reduces ad fraud by up to 40% in CTV environments
Standardized format includes publisher domain, seller account ID, and relationship type
Required by major ad exchanges like Google Ad Manager and Amazon Publisher Services

Overview

App-ads.txt is an advertising.txt file standard specifically adapted for connected TV (CTV) applications, developed by the Interactive Advertising Bureau (IAB) Tech Lab to combat ad fraud in the rapidly growing CTV advertising market. The original ads.txt standard was launched in May 2017 for web publishers, with the app-ads.txt adaptation following in 2018 to address the unique challenges of mobile and CTV app environments. CTV advertising spending has grown dramatically, reaching $21.2 billion in 2022 according to IAB data, making fraud prevention increasingly critical. The standard emerged as CTV viewership surged during the COVID-19 pandemic, with streaming hours increasing by 74% in 2020 alone, creating new opportunities for fraudulent actors to exploit the fragmented CTV ecosystem across platforms like Roku, Amazon Fire TV, Apple TV, and smart TVs.

How It Works

App-ads.txt operates through a simple text file that CTV app publishers place on their web servers, typically at a standardized location like example.com/app-ads.txt. This file contains structured lines that declare authorized digital sellers of the publisher's advertising inventory, with each line including three required fields: the publisher's domain, the seller's account ID, and the relationship type (DIRECT or RESELLER). When programmatic advertising platforms like Google's Authorized Buyers or The Trade Desk receive bid requests from CTV apps, they check the corresponding app-ads.txt file to verify that the seller is authorized. The verification process happens in real-time during the ad auction, with platforms cross-referencing the seller information against the published file. This creates a transparent chain of custody for CTV ad impressions, preventing unauthorized resellers from inserting themselves into the supply chain and ensuring that advertisers only purchase legitimate inventory from approved sources.

Why It Matters

App-ads.txt matters because CTV advertising represents one of the fastest-growing digital advertising segments, projected to reach $29.5 billion by 2024, yet it faces significant fraud challenges with an estimated 20-30% of CTV ad spend potentially wasted on invalid traffic. The implementation of app-ads.txt has reduced CTV ad fraud by approximately 40% according to Pixalate's 2023 report, saving advertisers billions of dollars annually. Beyond financial protection, it enhances measurement accuracy for CTV campaigns, which is crucial as advertisers shift more budget to streaming platforms. The standard also supports the growth of programmatic CTV advertising, which accounted for 65% of CTV ad spend in 2023, by increasing trust and transparency in automated transactions. Furthermore, it helps legitimate CTV publishers maximize their revenue by ensuring ads are sold through authorized channels, creating a healthier ecosystem for the entire streaming industry.