---
title: "Set up an application placement"
description: "Configure an in-app slot served through the ad API — the Ad category, Application OS and Display type selects, the API tab with the request URL and parameter table, the caveats (no Domain as default channel, size optional, the API-tab permission) and what to check when a banner never serves in the app."
type: "howto"
audience: [network-manager, admin]
keywords: [application placement, in-app, Android, iOS, ad API, API tab, request URL, ad category, Banner Ad, Interstitial Ad, Native Ad, Rewarded video, application OS, display type, DISPLAY_TYPE, placement key, channel]
ui_path: "Account → Publishers → site → zone → placement"
---

Fetch the complete documentation index at: https://epom.com/ad-server/docs/llms.txt. Use this file to discover all available pages before exploring further. Append .md to any documentation page URL to get its markdown version.

# Set up an application placement

## What it is and why

An **Application** placement serves into a native mobile app through the ad API: the app (or
your server) calls the request URL with the placement key and the device's ids, and only banners
whose ad category and OS match the slot are eligible. There is no ad tag for this type — the API
tab is the whole integration. The other specialist types are on
[Application, email and click-through placements](https://epom.com/ad-server/docs/guides/inventory/placement-mobile-email-other.md); mobile
*web* pages use the [Mobile Site Placement](https://epom.com/ad-server/docs/guides/inventory/placement-display.md).

**Example.** A publisher's Android news app has a 320×50 banner slot. It is an **Application
Placement** with Ad category *Banner Ad* and Application OS *Android*; the app calls the API
request URL from **Ad tags & API → API** with the placement key and the device's ids, and a
320×50 application banner marked *Banner Ad* / *Android* fills it.

## Typical scenarios

| You want | Create | Then hand over |
|---|---|---|
| A 320×50 banner slot in an iOS or Android app | **Application Placement**, Ad category *Banner Ad*, Application OS matching the app | The API request URL and parameter table from **Ad tags & API → API** |
| A full-screen interstitial or a rewarded video in the app | **Application Placement**, Ad category *Interstitial Ad* or *Rewarded video* | The same API URL; only banners with that category and OS are eligible |

## Step by step

Start from a saved placement of this type ([create one](https://epom.com/ad-server/docs/guides/inventory/placements-create.md)).

1. Open the placement. Beyond the shared fields, fill the app-specific selects:
   - **Ad category** — the ad format of the slot: *Banner Ad*, *Interstitial Ad*, *Native Ad* or
     *Rewarded video* (a new placement starts on *Banner Ad*);
   - **Application OS** — *iOS* (the default) or *Android*. A non-native application banner is
     eligible for the slot only when its OS and ad category both equal the placement's;
   - **Display type** — *As view* or *As activity*: how the app shows the ad. It is returned in
     the API response as `DISPLAY_TYPE`, unless the banner names its own.

   ![Application placement fields: ad category, application OS, display type](https://epom.com/docs-images/ad-server/placement-mobile-email-other/application-fields.webp)

2. Save, then open **Ad tags & API** → **API** tab: the request URL, the parameter table (`key`,
   `clientIp`, `clientUa`, `format`, device identifiers…) and sample responses. It is the only
   integration path for this type — call it from the app or from your server.

   ![API tab on an Application Placement](https://epom.com/docs-images/ad-server/placement-mobile-email-other/application-api-tab.webp)

## Caveats and exceptions

**Application placements have no Domain as default channel** — apps have no page domain for it to
read. If you segment reporting by channel, pass the channel explicitly as a request parameter.

**Display type is optional and nothing pre-selects a value** — a placement can be saved without
one. *Ad category* and *Application OS*, by contrast, are both defaulted and validated.

**Size is not required on an Application Placement.** Only **Site** and **Email** placements
require one; every other type that has a Size field leaves it optional.

**The application API tab needs its own permission.** Without it the Ad tags & API card has
nothing to show for this type and looks broken — ask your network admin for the grant.

Who can do this, and why there is no Preview button, are on
[Application, email and click-through placements](https://epom.com/ad-server/docs/guides/inventory/placement-mobile-email-other.md#caveats-and-exceptions).

## Not working?

| Symptom | Check | Where |
|---|---|---|
| The Ad tags & API card is empty on an Application Placement | Your role lacks the application API-tab permission | Your network admin — [User roles](https://epom.com/ad-server/docs/guides/admin/users-and-roles.md) |
| A banner never serves in the app slot | A non-native application banner needs the same **Application OS** and **Ad category** as the placement | The placement's two selects and the banner's |
| Save lands an error on **Ad category** | Validation errors from saving land on this field even when another part of the form caused them | Read the message; *Ad category* and *Application OS* are validated, *Display type* is not |
| No channel in reports for app traffic | Application placements have no **Domain as default channel** | Pass `channel` on the API request |

The symptoms common to all three types (Preview answers *Not Supported*, the Settings tab missing
on a share) are on
[Application, email and click-through placements](https://epom.com/ad-server/docs/guides/inventory/placement-mobile-email-other.md#not-working).

## Reference

The fields and their defaults:
[Application placement fields](https://epom.com/ad-server/docs/guides/inventory/placement-mobile-email-other.md#application-placement-fields)
on the hub. The API request, its parameters and responses:
[API tab, VAST tags and the JavaScript API](https://epom.com/ad-server/docs/guides/inventory/ad-tags-api-and-vast.md).

## Related

- [Application, email and click-through placements](https://epom.com/ad-server/docs/guides/inventory/placement-mobile-email-other.md)
- [Set up an email placement](https://epom.com/ad-server/docs/guides/inventory/placement-mobile-email-other-email.md)
- [Set up a click-through placement](https://epom.com/ad-server/docs/guides/inventory/placement-mobile-email-other-click-through.md)
- [Create a placement](https://epom.com/ad-server/docs/guides/inventory/placements-create.md)
- [API tab, VAST tags and the JavaScript API](https://epom.com/ad-server/docs/guides/inventory/ad-tags-api-and-vast.md)
- [Placement types reference](https://epom.com/ad-server/docs/reference/placement-types.md)