Can theme extension apps reference external data sources?

Topic summary

Main need: Evaluating Shopify for a client whose requirements involve product-related data that exceeds what Shopify’s native data model provides.

Limitations: While Shopify metafields and metaobjects are acknowledged, the poster considers the volume/complexity of the additional data too large to manage with those features alone.

Proposed approach: Use external data sources via microservices to supply the additional information at runtime.

Examples of data to retrieve: Product reviews, product-category-specific attributes, and product video URLs, fetched from an external service and surfaced in the storefront context.

Key question: Whether a theme (or theme extension) can reference and load such external data directly, enabling dynamic rendering of that information on product pages.

Status: No responses or decisions yet; the feasibility and recommended method for integrating external data remain open.

Summarized with AI on January 15. AI used: gpt-5.

I am currently validating Shopify against the requirements of a customer.
And there is a few requirements that base on data beyond what Shopify has in the data model.
Of course there is meta fields and meta objects, but the extra data is too much to use the meta fields / objects for it.

So I am thinking of external data source (external microservices) as solution path.
Can I load reviews or product category specific attributes or video URLs for a product from an external service?