Yahoo! JAPAN Ads (Conversion API)

Datafly Signal delivers conversions to Yahoo! JAPAN Ads (LINEヤフー) Display Ads server-to-server using the Conversion API. This recovers conversions that on-page measurement tags miss because of ad blockers, browser tracking prevention (ITP), or script failures, and matches them back to ad clicks using the yclid click identifier plus hashed first-party data.

Prerequisites

Before configuring Yahoo! JAPAN Ads in Signal you need three things from Yahoo: an Application ID, and the Conversion IO and Conversion Label from your Display Ads conversion tag.

Step 1: Create a Yahoo! Developer Network Application ID

1. Sign in to the Yahoo! Developer Network with the account that has access to your ad account.
2. Create a new application and copy its Application ID (Client ID). This is the credential Signal sends to authenticate every request.

Step 2: Find your Conversion IO and Conversion Label

1. In Yahoo! JAPAN Ads (LINEヤフー for Business), open Display Ads > Tools > Conversion Measurement.
2. Open the conversion you want to track and view its tag details.
3. Note the two values used by the Conversion API:
   • Conversion IO (yahoo_ydn_conv_io) — the account-specific conversion identifier.
   • Conversion Label (yahoo_ydn_conv_label) — the label for this specific conversion.

Configure in Signal

Once you have your Application ID, Conversion IO, and Conversion Label, configure the integration in Signal.

Configuration Fields

Management UI Setup

API Endpoint

POST https://ads-cv.yahooapis.jp/v1/
User-Agent: Yahoo AppID: <app_id>
Content-Type: application/json

Each conversion is sent as a single JSON object (not an array). A successful request returns HTTP 201. Invalid or duplicate conversions are silently excluded even within a 201 response — they are not retried.

Identity Signals

Yahoo matches each server conversion to an ad click using whichever of the following Signal provides. At least one is required, and more signals improve match rates.

How to send user data

Call datafly.identify() when a user logs in, registers, or completes a purchase:

datafly.identify("user-123", {
  email: "taro.yamada@example.co.jp",
  phone: "+819001234567"
});

Signal normalises and hashes these fields automatically before delivery.

Event Mapping

The Conversion API is a conversion-only endpoint. Page views and funnel mid-steps (product views, add-to-cart, checkout started) are not accepted and are dropped by the blueprint. Only conversion events deliver.

Default preset

To customise, edit the integration’s Field Mappings in the Management UI.

Example: Purchase conversion

Datafly.js call:

datafly.identify("user-123", {
  email: "taro.yamada@example.co.jp"
});
 
datafly.track("Order Completed", {
  order_id: "ORD-001",
  revenue: 12800,
  currency: "JPY"
});

Conversion API payload sent by Signal:

{
  "yahoo_ydn_conv_io": "1EALEzSJBNabcdEFGBE1",
  "yahoo_ydn_conv_label": "AB0ABCDEFGHIJKLMNOP123456",
  "event_time": 1717660800,
  "yclid": "YJAD.1717650000.1EALEzSJBNabcdEFGBE1",
  "hashed_email": "31c5543c1734d25c7206f5fd591525d0295bec6fe84ff82f946a34fe970a1e66",
  "yahoo_ydn_conv_transaction_id": "ORD-001",
  "yahoo_ydn_conv_value": 12800,
  "ip": "203.0.113.10",
  "user_agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) ...",
  "url": "https://example.co.jp/thanks/",
  "referrer": "https://example.co.jp/checkout/"
}

Deduplication

If you run both the on-page conversion tag and the Conversion API for the same conversion, send a stable yahoo_ydn_conv_transaction_id (Signal maps order_id here for purchases). Yahoo removes duplicate conversions that share the same transaction ID, so the conversion is only counted once. The transaction ID has a maximum length of 64 bytes.

Testing your integration

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