API Base URL¶
The single setting on the Parts Diagram theme block. Most stores leave it blank — and that's the right default.
What it does¶
When the storefront block boots, it needs to reach the Parts Diagram API to load diagrams, hotspots, and live pricing.
- Blank (default) — the block uses your store's Shopify
App Proxy, which routes
/apps/parts-diagram/*requests through Shopify to our API. No DNS or CORS configuration required. - Set to a custom URL — the block calls that URL directly instead. Use only if you have a dedicated API deployment (multi-environment staging, a private regional cluster, or a development tunnel).
For the overwhelming majority of stores, leave this blank.
When to set it¶
You only need a custom value when:
- You're testing a development build of the app on a sandbox store, and
the developer points you to a temporary tunnel URL such as
https://parts-diagram-dev-7.example.com. - You're piloting a private deployment of the app on infrastructure separate from the public production cluster.
- You have a multi-region setup and want a specific store to pin to a specific region's API.
In all three cases, the URL will be provided to you by the development team or your account manager.
How to set it¶
- Open Online Store → Themes → Customize.
- Switch to the product template that has the Parts Diagram block.
- Click the Parts Diagram block in the section list.
- Paste the full URL into API base URL — including
https://. - Click Save.
Reload the storefront in a private window to verify. If the diagram loads, you're done.
Reverting¶
To go back to the App Proxy default, clear the field, click Save,
reload the storefront in a private window. The block falls back to
the standard /apps/parts-diagram/* proxy path.
Common pitfalls¶
- HTTP not HTTPS — Shopify storefronts are HTTPS. An HTTP API URL will be blocked by mixed-content policy.
- Trailing slash — both
https://api.example.comandhttps://api.example.com/work; don't include path segments. - Stale dev tunnels — development tunnel URLs change frequently. If your storefront stops loading after a development cycle, blank the field, save, and the block falls back to the App Proxy.