My $5/month Cloudflare bill hit $4,868 because of an infinite loop

The invoice said $4,868.00. My Cloudflare account usually costs $5 a month. In January 2026, two bugs in two different workers wrote billions of rows to D1. I'm a solo developer on the Workers Paid plan. I don't have a billing department. I have a credit card and a vague hope that nothing goes catastrophically wrong. That hope cost me 18 days of stress, a near-suspension of my entire account, and a spam folder I should have been checking more carefully. TL;DR: Two code bugs wrote 4.83 billion rows to Cloudflare D1 in January 2026, generating a ~$4,868 overage on a $5/month account. After 18 days and four escalation channels, Cloudflare waived the full $4,586.64 invoice. I then built a three-layer circuit breaker system so it can't happen again. What went wrong with D1? Two separate bugs, two separate projects, both writing to D1 without anything to stop them. The embedding worker that couldn't stop writing Semantic Librarian is my Australian heritage records project. 1.4 million histor