// GMC add-on setup guide

How to set up API Diagnostics in Google Merchant Center

API Diagnostics only matters if you push products via the Content API for Shopping instead of an XML/CSV feed. It shows request volume, error rates, latency, and per-endpoint issues.

// Add-on
API Diagnostics
// Impact
For advanced users
// Setup time
5 steps · ~15-30 min
// Direct link
Open in GMC ↗

Requirements

  • ✓ Verified Merchant Center account
  • ✓ Content API for Shopping enabled (via Google Cloud project)
  • ✓ Active API traffic (at least one request in the last 7 days)

Step-by-step setup

  1. 1
    Open API Diagnostics
    Merchant Center → Settings → API → Diagnostics.
  2. 2
    Review overall error rate
    Chart shows request volume + error % over 7/30 days. Target: under 1% error rate.
  3. 3
    Drill into error types
    Click any bar to see the breakdown: 400 Bad Request, 401 Unauthorized, 403 Forbidden, 500 Server Error.
  4. 4
    Check latency
    p50/p95/p99 request latency. Above 2s p95 usually means retries are hurting throughput.
  5. 5
    Inspect per-method usage
    Table shows which methods (products.insert, products.list, etc.) generate most calls + errors.

Common issues + how to fix

⚠
400 Bad Request
Malformed JSON or missing required fields. Check the error message body.
⚠
401 Unauthorized
OAuth token expired or scope wrong. Ensure "https://www.googleapis.com/auth/content".
⚠
Quota exceeded
Default is 60 requests/second per user. Request higher quota in Google Cloud console.

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