Seeking Advice: Google Ads Conversion Tracking for Simple Shopify Store
We’re re-launching a 1-page Shopify store for our health supplement and need a 2nd pair of eyes on ideal Google Ads conversion tracking.
Stack/Setup:
Shopify with ‘Google & YouTube app’
Google Merchant Center (GMC)
GA4
Google Ads
Klvayio (audience management)
SKIO (subscription management)
Context:
E-commerce health supplement startup
Goal: Purchases at sustainable CPA
Previous agency: Poor performance & shit setup (CPA ~3x retail price on both Google & Meta)
Limited budget: £20K (~$25K USD) /month across Google+Meta
Low organic CR (~0.5% visit to purchase)
Rate-limiting-step: Huge drop-off from initial checkout to purchase (meaning, we can capture a fair amt of ini.checkouts; not so many purchases)
Google Ads Campaign Structure:
Generic Search (Phrase): Max conv. vol |Initiate Checkout
Brand Search (Exact): Max conv. vol |Purchase
Standard Shopping: Max conv. vol |Initiate Checkout
Remarketing: Max conv. vol |Purchase(targeting checkout abandons)
Plan:
Optimize for max initiate checkout volume initially, except for Remarketing & Brand (max purchase volume). Switch to max purchase volume optimization across board, once we have >30 purchases within 30 days.
Questions:
Are our conversion goals set up correctly?
How should we handle primary vs secondary goals?
Should we use both the ‘Google Shopping App’ and GA4 events?
If not both, is there an advantage to bid on GA4 events over Google Shopping App events? (we’d want as rich data as possible; but would prioritise accurate google-ads ‘preferred’ focussed tracking)
BONUS: Does our strategy make sense, or would you approach it differently?
BONUS: Any feedback on our GA4 setup?
Additional Info:
Planning to test Performance Max vs Standard Shopping/Search after 1-2 months
Please stay humble: We’re Open to professional help, but trying to learn ourselves
I’ve personally got deep experienced in app marketing and every other channel incl. programmatic, but fairly new to specifically Google Ads for e-commerce
Any advice or feedback is greatly appreciated!
The short answer is:
Your conversion goal structure and initial bidding strategy are generally sound for your low-volume and high drop-off context, but your tracking setup must be hardened to ensure data fidelity.
You should use a server-side implementation for both the Purchase conversion action from the Shopify ‘Google & YouTube app’ and the Google Analytics 4 Purchase event.
This is non-negotiable for low CR and high CPA accounts because browser-side tracking is inherently unreliable due to ad-blockers and ITP, which directly impacts your Smart Bidding performance.
Use Purchase as your Primary conversion action across all campaigns for bidding, and set Initiate Checkout as a Secondary conversion action for observation and audience creation, only using it for bidding in the Generic Search campaign temporarily until you hit your 30-conversion threshold.
Leverage the Google Ads API via a server-side setup like Google Tag Manager and Stape on Google Cloud Platform to send back accurate, de-duplicated conversion data, including Enhanced Conversions, which is a powerful way to mitigate data loss and directly solves your issue of poor performance from a “shit setup.”
The long answer is:
Your plan to initially optimize for Initiate Checkout on non-Brand/Remarketing campaigns and then switch to Purchase is a well-reasoned strategy for bootstrapping Smart Bidding data, as the system needs a statistically significant number of conversions (ideally over 30 per month) to function optimally, addressing your ‘limited budget’ constraint with a lower-funnel micro-conversion.
The core problem, however, lies in your current stack’s reliance on client-side tracking, which is likely the root cause of the previous agency’s “poor performance” and “shit setup.”
The huge drop-off you observe between initial checkout and purchase could be partly due to genuine funnel friction, but it is almost certainly exacerbated by under-reporting of the final Purchase event in Google Ads, skewing your CPA and crippling your Smart Bidding algorithms.
To fix this, you need a robust server-side tracking solution.
The correct approach is to run both the Google & YouTube app’s tracking and the GA4 events, but they must be carefully managed to prevent double-counting.
You should not bid on two separate Purchase conversion actions.
The Google Ads API is the key component here.
By implementing a server-side Google Tag Manager container on Google Cloud Platform or a managed solution like Stape, you can receive data from the Shopify frontend, and before sending the Purchase conversion to Google Ads, you can: one, de-duplicate it against the Google & YouTube app’s Purchase tag to ensure only one purchase is counted, and two, enrich it with first-party customer data like hashed email and phone number via Enhanced Conversions.
This server-side process, driven by the Google Ads API for the final conversion upload, provides Google’s Smart Bidding algorithms with the most accurate, reliable, and privacy-compliant data feed possible, directly improving your CPA by correctly attributing sales and training the bidding model more effectively.
This is cost-effective because the investment in a server-side solution directly leads to lower CPA and higher ROAS, quickly recouping the modest costs of a service like Stape or a GCP instance.
For your Primary conversion, designate the server-side Purchase event as the one to bid on; mark the Initiate Checkout as Secondary (for reporting only) across your Purchase-optimized campaigns to ensure bidding remains focused on the high-value action while retaining visibility into the critical drop-off point, and then flip the Initiate Checkout goal to Primary in your Generic Search campaign until you cross the 30 Purchase conversion mark.
Finally, for an excellent, detailed look at your funnel, you should use the BigQuery API to export your raw GA4 event data into BigQuery for advanced, unsampled analysis in Looker Studio, providing deep, granular insights into where exactly users drop off, a feature not easily replicated in the standard GA4 interface, thereby enabling targeted funnel optimization.
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