Google Ads is deprecating the legacy offline conversion import endpoint on 1 August 2025. Advertisers must migrate to the new Data Manager API or risk losing the conversion signals that power Smart Bidding.
The advertisers who will feel this most are the ones running value-based bidding on lead gen. Without the conversion signal, Smart Bidding goes blind.
Google Ads is retiring the legacy offline conversion import endpoint on 1 August 2025. Every advertiser running lead generation campaigns that feed CRM conversions back into Google needs to migrate to the new Data Manager API before that date or lose the signal chain that powers Smart Bidding.
The change consolidates what used to be a fragmented process. The old method required manually uploading conversion data through the Google Ads API or UI. The Data Manager API centralises all first-party data connections, including offline conversions, enhanced conversions and customer match lists, into a single pipeline. Google says the new system processes data faster and supports more granular conversion tracking, which feeds directly into bidding algorithms.
For most advertisers, this is not optional. If your lead gen campaigns rely on feeding closed-deal data back into Google to optimise for downstream value, the legacy endpoint stops working on 1 August. Google has published migration documentation, but the timeline is tight for teams running complex CRM integrations.
Deadline for migrating offline conversion imports to the Data Manager API
The broader context matters here. This is part of Google's ongoing push to consolidate first-party data handling into a unified layer. Enhanced conversions, customer match and now offline imports all route through the same infrastructure. Google wants a single pipe for all advertiser data, which gives them more control over signal quality and processing speed.
For agencies managing multiple accounts, the migration workload compounds. Each account with offline conversion tracking needs individual migration. The Data Manager API uses different authentication patterns and data schemas, so existing scripts and integrations need rebuilding.
Why it matters
Offline conversion data is the highest-value signal in lead generation. It tells Google which clicks turned into actual revenue, not just form fills. Losing that signal does not just reduce reporting accuracy. It degrades bidding performance, which means higher CPAs and lower-quality leads. The advertisers who migrate early get cleaner data flowing into their bidding models. The ones who wait until July will be scrambling.
What to do about it
Audit every Google Ads account for offline conversion imports. If any account uses the legacy upload method, start the migration now. The Data Manager API documentation is live on the Google Ads developer site. Build in testing time because the new API handles data differently, and you want to confirm conversion attribution is matching before the old endpoint disappears. If you are using a CRM integration platform like Zapier or HubSpot, check whether they have updated their Google Ads connectors to use the new API.
Do not wait until July.