Google is changing how advertisers connect first-party data and conversion signals to Google Ads. If your team is manually uploading CSV files or hitting the ConversionUploadService API directly to report offline conversions, this migration affects you directly. As of June 15, 2026, the legacy offline conversion import workflow is blocked in the Google Ads API for any developer token that wasn't actively using it before January 2026. The Google Data Manager API is the required path going forward — and understanding what it is (and what it isn't) is now a prerequisite for anyone serious about Google Ads conversion tracking.
TL;DR — The Google Data Manager API is Google's new standard for programmatic conversion data uploads, replacing the legacy ConversionUploadService in the Google Ads API. It's blocked for new tokens as of June 2026. Beyond migration, the Google Data Manager API represents a shift toward centralized, multi-destination measurement — one data connection can feed Google Ads, GA4, and Search & Display 360 simultaneously. It also enables multi-source measurement, letting you stack web tag data with API-uploaded data for the same conversion event to improve attribution and match quality.
What Is the Google Data Manager API?
Before getting into what the Google Data Manager API does, a naming clarification that trips people up: Google Data Manager API and Google Ads Data Manager are related but distinct.
Google Ads Data Manager is the UI tool built into Google Ads (Tools & Settings → Data Manager). It's the interface where you connect data sources, configure imports, and monitor data health — no code required for many common setups.
The Google Data Manager API is the programmatic API layer that sits beneath and alongside that interface. It's a separate API from the Google Ads API, and it's the path for teams that need to automate conversion data uploads, build custom pipelines, or connect data sources that aren't available through the UI's native integrations. This post is primarily about the Google Data Manager API — though it naturally overlaps with the Google Ads Data Manager UI, since they serve the same underlying purpose.
Together, they're the single place where first-party data — CRM records, offline sales data, hashed customer lists — connects to Google's advertising infrastructure. You can use Google Ads Data Manager to:
- Connect data sources — CRMs, data warehouses, Google Sheets, CDPs
- Configure and automate offline conversion imports (now called enhanced conversions for leads)
- Upload and sync Customer Match audience lists
- Monitor data health, match rates, and upload diagnostics
The Google Data Manager API extends this to teams that need programmatic control — enterprise advertisers, agencies managing multiple accounts, and measurement platforms building integrations on top of Google's infrastructure.
Neither is a new campaign type or bidding feature. It's infrastructure — infrastructure that directly determines how much of your first-party conversion data actually reaches Google's bidding systems, which directly determines how well Smart Bidding can optimize your campaigns.
Google Data Manager API vs. the Legacy Google Ads API
The legacy method for offline conversions used the Google Ads offline conversion import workflow: either manual CSV uploads through the Google Ads interface, or programmatic uploads via the ConversionUploadService in the Google Ads API. Both paths have been replaced.
Here's how the two approaches compare across the dimensions that matter most:
| Capability | Legacy API / CSV Upload | Google Data Manager |
|---|---|---|
| Integration method | Manual file uploads or custom API calls | Connected, scheduled data sources |
| CRM connectivity | Custom build or manual export/import | Native connections (Salesforce, HubSpot, and more) |
| Data health monitoring | API response-based — requires parsing logs and response objects | Built-in dashboard with match rate and error reporting |
| Enhanced Conversions for Leads | Separate implementation | Integrated within GDM |
| Customer Match | Separate upload process | Unified within GDM, supports automated refresh |
| Match rate visibility | Indirect — requires API response parsing | Dashboard with match rate and error diagnostics |
| Engineering overhead | High — custom pipeline required | Low to medium — configuration-first |
| Forward support status | Being deprecated | Active — Google's recommended path |
The biggest practical difference is the operational model. Legacy API implementations required custom engineering to build and maintain a data pipeline. Google Data Manager shifts toward a configuration model — connect a data source once, map your fields, and the connection runs automatically on a schedule. For teams that built custom pipelines, the migration requires retooling. For teams uploading CSVs manually, Google Ads Data Manager is a meaningful upgrade in reliability and visibility.
Why Google Is Making This Change
This isn't a random platform cleanup. Three distinct forces are pushing Google to consolidate first-party data under a single system.
Privacy-first attribution is the new baseline. Third-party cookies are either gone or degraded across the browsers and environments that matter most. Offline conversion data — reported first-party by the advertiser from their own CRM or sales system — is one of the highest-quality attribution signals Google Ads can receive. By making offline conversions easier to connect and more reliable to maintain, Google is investing in the signal category that holds up in a cookieless world. This aligns directly with why enhanced conversions have become a non-negotiable part of any serious Google Ads setup.
First-party data is becoming the differentiator. Advertisers who can connect their CRM, their closed-deal data, and their customer lists to Google Ads will produce better Smart Bidding performance than those who can't — not because their campaigns are smarter, but because their conversion signals are stronger. GDM removes the technical friction from doing this. Google's interest aligns with advertisers' here: better data in means better performance out, which means more spend on Google Ads.
Google is centralizing measurement infrastructure. The Google Data Manager API represents a shift toward a single, centralized measurement layer that can serve multiple destinations simultaneously — Google Ads, GA4, Search 360, and Display 360 — from one data connection. Rather than maintaining separate pipelines for each destination, advertisers can route the same conversion signal to multiple Google products through one integration. This also enables multi-source measurement: stacking web tag data with Google Data Manager API uploads for the same conversion event, so the two sources complement each other and improve overall attribution and match quality. The legacy API's architecture didn't support this kind of unified, multi-destination data routing.
What the Google Data Manager API Can Do
Google Data Manager handles several first-party data use cases, all under one roof.
Offline Conversion Imports / Enhanced Conversions for Leads. These are the same thing — Google renamed offline conversion imports to "enhanced conversions for leads" in preparation for the Data Manager API adoption. Connect your CRM or data warehouse, map the required fields (GCLID or hashed email, conversion action name, conversion timestamp, and optionally conversion value), and the import runs on a configured schedule. When a prospect submits a form on your site, the hashed email is captured at form submission. When that same prospect converts in your CRM later, the data is matched to the original ad click with higher accuracy than GCLID-only imports. The hashed email acts as a persistent identity signal that survives the time gap between lead submission and deal close. Google is recommending all advertisers currently using standard offline conversion import upgrade to enhanced conversions for leads to get better match rates, cross-device attribution, and engaged-view conversions.
Multi-Destination Measurement. One of the more significant capabilities of the Google Data Manager API that isn't loudly advertised: a single data connection can feed multiple Google products simultaneously. The same conversion signal can be routed to Google Ads, GA4, Search 360, and Display 360 without maintaining separate upload pipelines for each. For advertisers running across multiple Google products, this reduces engineering overhead and keeps measurement consistent across destinations.
Multi-Source Measurement. The Google Data Manager API also enables stacking web tag data with API-uploaded data for the same conversion event. Rather than choosing between your Google tag and your backend data, you can use both — the tag captures what it can from the browser, and the API upload supplements with additional signals from your CRM or order system. Google deduplicates within a single conversion action using transaction ID, so you don't double-count; you just get better coverage and match quality than either source alone.
Customer Match Audience Uploads. Upload hashed customer data — emails, phone numbers, mailing addresses — and Google matches these against signed-in Google accounts to create targetable audience segments. Google Ads Data Manager supports automated list refreshes from connected data sources, so your Customer Match audiences stay current without requiring a new manual upload each month.
Data Diagnostics and Match Rate Reporting. The data health dashboard shows match rates per data source, upload success rates, row-level failure reasons, and trend data over time. For any account where conversions are a primary bidding signal, this visibility has direct performance implications. Note: the diagnostic dashboard is not a live real-time feed — it reflects processed upload data, with some reporting latency.
Who Needs the Google Data Manager API?
If you're importing offline conversions today through any method, migration to the Google Data Manager API is required. As of June 15, 2026, the legacy ConversionUploadService is blocked for developer tokens that weren't actively using it between January and June 2026. Practically speaking: any advertiser or agency setting up new conversion tracking via API with a token that hasn't been used for this purpose before must use the Google Data Manager API. There's no legacy path available for new implementations.
One thing worth noting: the Google Data Manager API is relatively new, and its native integration library is still limited compared to what the legacy workflow supported through third-party tools. Advertisers with custom integrations built on the legacy API will need to rebuild them for the Data Manager API. Native CRM connectors cover major platforms (Salesforce, HubSpot), but teams using less common CRMs or custom data pipelines will likely need the API directly.
Beyond the forced migration, the Google Data Manager API creates genuine value for specific advertiser profiles.
B2B companies with sales-assisted funnels. A prospect submits a demo request today and signs a contract in 45 days. Without an offline conversion import, Smart Bidding is optimizing for demo requests — not contracts. If your cost-per-demo looks reasonable but your cost-per-closed-deal is astronomical, the problem is almost always missing offline conversion data. GDM is the mechanism for closing this gap.
Businesses where conversions happen off the website. Phone sales, in-store purchases, showroom consultations — any business where the final conversion doesn't produce a website thank-you page is flying blind in Google Ads without an offline import pipeline. GDM is the infrastructure that makes this data actionable.
Advertisers using or planning to use Customer Match. If you're targeting existing customers, suppressing converted users, or building lookalike segments from your CRM, GDM makes the upload and refresh cycle significantly less labor-intensive. Automated list sync means your audiences stay current without manual intervention.
Any growth-stage team that wants first-party data infrastructure. Even if offline conversion volume is currently small, building a GDM connection early establishes the data pipeline before Smart Bidding scale makes the gap expensive. It's easier to configure GDM when volume is low than to retrofit it when degraded signals are actively hurting performance at scale.
One use case Google doesn't explicitly document but which is fully supported: using the Google Data Manager API as your primary (or sole) source of conversion tracking, similar to how teams used the legacy API before. While Google's documentation emphasizes the Data Manager API as a supplement to web tags, you can build an implementation where the API is the centralized conversion tracking layer — routing conversion data directly from your CRM or attribution platform. Measurement tools like FunnelTrack are built to integrate directly with the Google Data Manager API in exactly this way, letting you manage conversion signals from a single measurement layer rather than stitching together multiple tag implementations.
For teams also investing in server-side tagging infrastructure, the Google Data Manager API is a natural complement — server-side tagging improves web conversion signal quality at the tag layer while the Data Manager API handles the offline and CRM signal pipeline, giving Google Ads the most complete picture of actual business outcomes.
How to Get Started with Google Data Manager
Access Google Ads Data Manager from inside Google Ads: Tools & Settings → Data Manager. For programmatic access, the Google Data Manager API is the developer entry point. If you're migrating from the legacy ConversionUploadService, see the Google Ads API conversion management overview for current migration guidance.
Step 1: Audit your current setup. Before touching anything, document what exists. How are offline conversions currently being imported — CSV, direct API, native CRM integration? Who owns the process? What conversion actions are receiving imported data? This audit prevents double-counting and establishes a clean migration baseline. Check your conversion action settings in Google Ads to confirm which actions are currently set to receive uploaded conversions.
Step 2: Confirm auto-tagging is enabled. Auto-tagging must be active in Google Ads for GCLIDs to be appended to your ad URLs. Without auto-tagging, there's no GCLID to match against when you import an offline conversion. This is the single most common reason offline conversion match rates are low or zero — and it's easy to miss if your account was set up years ago.
Step 3: Connect your data source. Google Ads Data Manager supports several connection types. Native CRM integrations cover major platforms including Salesforce and HubSpot. Google Sheets works for teams managing smaller data volumes manually. For custom pipelines — including teams using the Google Data Manager API directly — the API layer accepts the same connection configurations programmatically. Keep in mind that native third-party integrations are still relatively limited; if your CRM or data source isn't listed, you'll likely need the API. Choose the connection type based on where your data lives and how much automation your team needs.
Step 4: Map your fields. GDM requires specific fields for offline conversion imports: the click identifier (GCLID or hashed email for enhanced conversions for leads), the conversion action name exactly as it appears in Google Ads, the conversion timestamp in the correct format, and optionally the conversion value. Field mapping errors are the second most common failure point after auto-tagging. Take time to validate that your data source exports match the expected format before activating the connection.
Step 5: Run a validation pass before going live. Google Ads Data Manager includes diagnostic tooling that shows match rate estimates before you activate a connection for live bidding. Run a historical data sample through — ideally 30 to 90 days of closed conversions — to confirm field mapping is correct and match rates are in a reasonable range. For GCLID-based imports, expect 30–70%+ match rates depending on how consistently your CRM captures GCLIDs. For hashed-email-based enhanced conversions for leads, match rates are typically higher when email capture is consistent.
Step 6: Monitor actively for the first 30 days. Set a recurring reminder to review the data health dashboard in Google Ads Data Manager weekly for the first month after migration. Match rate drops, connection failures, and field format errors surface here — and catching them early prevents extended periods where Smart Bidding is receiving degraded or missing conversion signals. A lapse in offline conversion data looks similar to a campaign performance problem in the Google Ads interface, and misdiagnosing it as a bidding or creative issue wastes time and budget.
The most common reason offline conversion imports fail is a mismatch between the GCLID captured at form submission and the format expected during import. Auto-tagging must be enabled in Google Ads, and your landing pages or CRM must pass the GCLID through to the lead record at the moment of form submission — not captured retroactively. Audit this before migrating, not after you've gone live and are troubleshooting a 0% match rate.
Frequently Asked Questions
The Google Data Manager API is a programmatic API for uploading first-party conversion data to Google's advertising infrastructure — offline conversions, enhanced conversions for leads, and Customer Match audiences. It replaces the legacy ConversionUploadService in the Google Ads API. It should not be confused with Google Ads Data Manager, which is the UI tool inside Google Ads; the Google Data Manager API is the developer layer that powers it programmatically.
Yes. As of June 15, 2026, offline conversion uploads via the Google Ads API are blocked for developer tokens that were not actively using them between January and June 2026. Any new conversion tracking implementation via API must use the Google Data Manager API. See the Google Ads API conversion management docs for migration guidance.
They're the same thing — Google renamed offline conversion imports to "enhanced conversions for leads" in preparation for the Google Data Manager API adoption. Enhanced conversions for leads is the upgraded version that adds hashed user-provided data (email) as an additional match key alongside GCLID, improving match rates and enabling cross-device attribution and engaged-view conversions. Google recommends all advertisers on the legacy offline conversion import upgrade to enhanced conversions for leads.
Ready to Migrate to Google Data Manager?
We help advertisers transition offline conversion pipelines to GDM without losing data continuity or disrupting Smart Bidding performance. Let's map out your migration.
Schedule a Free Call