I’m a solo operator with no paying customers yet. I wanted more predictable baseline costs while iterating on a side project, so I migrated from App Engine to Cloud Run.

I fed my setup, budget, and constraints as context into Gemini CLI, asked it to search official documentation and best practices, and followed that guidance.

I removed –min-instances=1, expecting autoscaling to reduce idle spend. The commit message claimed “60% cost savings.” The actual outcome was roughly an 1,800% increase and a surprise decline message when I went to buy coffee on my credit card.

From Nov 2 to Dec 14, Cloud Run accrued ~$4,676. There was no traffic spike, no abuse, no application bug. The services were mostly idle.

What compounded: CPU and memory were over-provisioned (4 CPU, 16Gi) from earlier experimentation. Each deploy created a new revision, and I deployed frequently while iterating. Those revisions must have stayed warm longer than expected. Autoscaling plus revision sprawl meant more active resources than intuition suggested, even without traffic.

The billing alert failure: I had alerts enabled at $50. I received one early notification, then silence as spend climbed another $4,600. There were no clear signals that my cost profile had materially changed.

I contacted Google Cloud Billing Support looking for clear guidance or partial relief. After review, they declined any adjustment and closed the case. As a solo dev without an account team, there was no escalation path beyond accepting the charges.

Where it stands now: After right-sizing resources and cleaning up revision sprawl, daily costs dropped from ~$200 to under $5 on my billing dashboard. I’m cautiously optimistic but not certain it’s fully resolved.

For those running Cloud Run longer term: How do you actually cap downside as a solo dev? Do you set hard budget caps and accept downtime? Are there deployment patterns that avoid revision sprawl? Is App Engine still preferable purely for cost predictability? What guardrails work that don’t depend on constant manual billing checks?

I wasn’t chasing scale. I was trying to be careful with money while building alone. I’d appreciate hearing what others would do differently.