> Lines that don't follow the format (ad system domain, seller ID, DIRECT or RESELLER, optional certification ID) are skipped by crawlers, so they authorize nothing.

Source: https://appsupplyindex.com/fix/malformed-app-ads-txt-lines · Updated: 2026-10-07 · License: CC BY 4.0 (App Supply Index)

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[Learn](https://appsupplyindex.com/learn/) · How to fix

# Malformed app-ads.txt lines: what crawlers ignore

Updated Oct 7, 2026 · data from 12 App Store genres · top free + top grossing charts · US · iOS + Android

**Short answer:** Lines that don't follow the format (ad system domain, seller ID, DIRECT or RESELLER, optional certification ID) are skipped by crawlers, so they authorize nothing.

**291 of 883**
ad-monetized top US apps in this index have this finding (33%)

## Why it matters

Typical problems: a missing domain extension, a missing comma, or a relationship value other than DIRECT or RESELLER.

## How to fix it

1. Fix each flagged line to the standard format.

Before

```
pubmatic, 162439, RESELLER, 5d62403b186f2ace
smaato.com, 1100052485, RESELLER 07bcf65f187117b4
```

After

```
pubmatic.com, 162439, RESELLER, 5d62403b186f2ace
smaato.com, 1100052485, RESELLER, 07bcf65f187117b4
```

## Apps with this finding

Each report lists the exact lines involved.

- [Castle Busters](https://appsupplyindex.com/app/ios-6746328263) · Voodoo
- [Paper.io 2](https://appsupplyindex.com/app/ios-1423046460) · Voodoo
- [Mob Control](https://appsupplyindex.com/app/ios-1562817072) · Voodoo
- [Hole.io](https://appsupplyindex.com/app/ios-1389111413) · Voodoo
- [Marble Sort! - Color Puzzle](https://appsupplyindex.com/app/ios-6754558455) · Voodoo
- [Wizz App - chat now](https://appsupplyindex.com/app/ios-1452906710) · VLB
- [Weather Pro · Radar Alerts](https://appsupplyindex.com/app/ios-1137406490) · BUCKET LIST LABS S.L.
- [Authenticator ℠ App](https://appsupplyindex.com/app/ios-6754900760) · BEGAMOB GLOBAL LIMITED
- [iCardiac: Heart Rate & Health](https://appsupplyindex.com/app/ios-6468660073) · BEGAMOB GLOBAL LIMITED
- [Universal Remote TV Control ·](https://appsupplyindex.com/app/ios-1581765635) · BEGAMOB GLOBAL LIMITED
- [FaceVital: Health Monitor](https://appsupplyindex.com/app/ios-6773569672) · BEGAMOB GLOBAL LIMITED
- [Glucera: Blood Sugar Tracker](https://appsupplyindex.com/app/ios-6796661353) · BEGAMOB GLOBAL LIMITED

[All apps →](https://appsupplyindex.com/apps)

## Related

- [What is app-ads.txt?](https://appsupplyindex.com/learn/what-is-app-ads-txt)
- [DIRECT vs RESELLER](https://appsupplyindex.com/learn/direct-vs-reseller)
- [How the index checks files](https://appsupplyindex.com/methodology)

Based on the [IAB Tech Lab
ads.txt/app-ads.txt](https://iabtechlab.com/ads-txt/) and [sellers.json](https://iabtechlab.com/sellers-json/)
specifications. Numbers are automated observations of public files on the date above.