Cloud Cost Sense
Why Firestore Costs Grow
Firestore cost is often driven by read patterns, list screens, aggregation design, and repeated document fetching.
Reads are the usual surprise
Firestore charges by operations. A feed that loads posts, authors, comments, and like counts separately can multiply reads far beyond page views. This is why a small-looking screen can become the main cost driver.
Design for list screens
Store display-ready fields such as authorName, commentCount, likeCount, thumbnailUrl, and lastActivityAt on list documents when appropriate. This reduces repeated joins and makes pagination cheaper.
When to reconsider
If the product needs complex reporting, relational filters, frequent aggregations, or admin dashboards across many entities, compare Cloud SQL before committing to a Firestore-only model.