Google Offline Conversions API

Overview

Signals sends conversions that happened away from your website to Google Ads: phone orders, bookings, in-store sales and outcomes recorded in a CRM. Google uses them to attribute conversions to your campaigns and to optimize delivery.

Use this destination when the conversion lives in a system Signals can read, such as a CRM, a file drop, a database or a warehouse.

If you are reporting a change in lead status, use Google Enhanced Conversions for Leads. For in-store sales matched against a product catalog, use Google Store Sales Conversions.

Supported sources

Sources supported by Google Offline Conversions API

Category	Supported
API	Datahash API
CRM	ActiveCampaign Agile Apptivo Attio Bexio Bitrix24 Capsule Close Coevera Copper Freshsales HubSpot Insightly Kommo LeadSquared Microsoft Dynamics Monday Odoo Pipedrive Salesforce VTiger Zithara Zoho
Database	Apache Cassandra ClickHouse CockroachDB Couchbase CouchDB IBM DB2 MariaDB Microsoft SQL Server MongoDB MySQL Oracle PostgreSQL
File & storage	Files - AWS S3 Files - GCP Files - FTP Google Drive Microsoft OneDrive Box Dropbox Filebase BackBlaze Cloudian DigitalOcean Linode MinIO OVHcloud Tencent Vultr Wasabi
Warehouse	Amazon Redshift Google BigQuery Snowflake

Prerequisites

Before connecting Google Offline Conversions, make sure you have:

A Google Ads account, and the manager account ID above it.
Server-side API permission on that account.
Conversion actions already created in Google Ads for the outcomes you intend to report.
A Datahash Studio account with the target project selected.
A source connected in the same project. The identifiers and event details Google receives come from that source mapping, not from this destination.

Authentication

In Studio, open Destinations, find Google, and click the Offline Conversions tile. This connector uses single sign-on only; there is no manual credential path.

Click Sign in with Google.
Complete Google’s consent flow, choosing the account that has access to your Google Ads account.

Configuration

Enter the Login Customer ID, which is the manager account ID.
Enter the Customer ID of the Google Ads account conversions should land in.
Give the connection a name.
Map each source event name to the corresponding conversion action in Google Ads. Use the plus icon to add rows.
Click Finish.

The properties sent with each event have to satisfy the requirements of the conversion action you map it to, so an action expecting a value needs a value on the event.

Google identifies the account you are writing to with two IDs. The Customer ID is your Google Ads account. The Login Customer ID is the manager account, sometimes called the MCC, that sits above it. Getting them the wrong way round is the most common setup error on this connector.

Data & identifiers

Send identifiers already hashed where you can. Plain text also works: they are normalized and SHA-256 hashed before they reach Google.

Required

Field	When it is required
Event time	Always. UNIX timestamp. Use the time of the conversion, not the time of upload.
Event name	Always.
Last modified date	Always.
Email address	Always. This is the primary match key.
Currency	Purchase events only. The three-letter currency code.
Value	Purchase events only.

Optional

Field	Format
Last name	Letters only, lowercase, trimmed, no punctuation.
Date of birth	DD/MM/YYYY.
Google click ID	The click identifier for the conversion. If you set this, do not set either iOS variant.
iOS click identifiers	Two exist, one for app conversions and one for web. Set at most one click identifier in total.
Subscription ID	Similar to an order ID, for a subscription in this transaction.
Number of items	How many items the conversion covered.
Browser user agent	Sent unhashed where your source holds it.
Browser IP address	Sent unhashed where your source holds it.

Google does not accept a phone number on this connector, unlike the other offline destinations, so email is the only personal identifier that drives matching. Nor does it accept the city, state, country or postcode fields. Make sure email is populated on every record you send.

Best practices

Populate email on every record. Without it there is nothing for Google to match, and phone is not an alternative here.
Create the conversion actions in Google Ads before configuring the mapping.
Use the conversion time as the event time rather than the upload time, or Google will attribute against the wrong window.
Send the Google click identifier where your source captured it. On offline conversions it is the strongest signal available.
Set at most one click identifier per conversion. The three are mutually exclusive.

Troubleshooting & FAQ

The account IDs will not validate. They are probably swapped. The manager account ID belongs in Login Customer ID.

No conversion actions to map. They have not been created in Google Ads yet. Create them there first.

Conversions are rejected. The event is probably missing a property the conversion action requires, such as a value. Check what the action expects in Google Ads.

Match rates are low. Check email is populated and cleanly formatted. Adding a phone number will not help on this connector.

Conversions attributed to the wrong period. Check the event time carries the time of the conversion and not the time the file was uploaded.