Source-linked reports: Amounts and outcomes come from the original reports and linked replies.
RetainDB: a reported $36k bill from a queue loop with 81 users.
Reddit user alameenswe, building RetainDB on Workers, KV, Durable Objects and Queues, reports a Cloudflare bill of about $36k for one month with 81 users; the post body says $35,000. He attributes it to a queue consumer that re-queued async writes, 12 unbatched Durable Object writes per memory write and a kv.list() authentication fallback.
What happened
- Reported cause
- Unbounded loop
- Incident date
- Date not recorded
- First reported
- Date not recorded
Latest reported outcome
The author says fixes were deployed and the bill was sent to Cloudflare support with a full explanation. In a later Reddit reply, he says he had not paid the bill, had emailed Cloudflare saying he could not afford it, received no reply and changed the architecture.
View this update in the timelineOriginal sources
- Original Reddit post
- ServerlessHorrors summary with outcome note
- PPC Land report on the thread update
- Author’s bot-traffic clarification
- Author’s later payment and support update
Each entry links to the report or reply it describes.
Case timeline
Undated
Reddit post reports the bill
Open original sourceThe author reports about $36k ($35,000 in the body) for one month with 81 users, listing KV writes at $15,635, KV reads at $8,306, Durable Object rows written at $3,962 and KV list operations at $2,870, and describes a fix for each of three bugs.
ServerlessHorrors lists the case
Open original sourceServerlessHorrors summarizes the post with the same line items; its conclusion says fixes were deployed, the bill was sent to Cloudflare support with a full explanation, and it is unknown whether Cloudflare will credit it.
PPC Land reports a thread update
Open original sourcePPC Land reports that the author later wrote in the thread that most requests came from bots, that a rate limiter written earlier had not been wired in during a migration, and that requests dropped sharply after enabling Cloudflare’s rate limiter.
Undated
Author adds bot traffic and rate limiting
Open original sourceThe author says most requests came from bots, that a previously written rate limiter was not wired in during the migration and that requests dropped sharply after enabling Cloudflare’s rate limiter.
Undated
Author reports an unpaid bill and unanswered emails
Open original sourceAsked whether he paid the bill, the author says no. He says he emailed Cloudflare explaining he could not pay, received no replies and changed the architecture.
More to read
D1 status writes: an author reports a 150-dollar charge and refund.
@wofuhuola describes a generated tool writing Reddit post statuses globally every five minutes and deleting expired rows. The author says one month cost 150 dollars, went unnoticed for three months, and was later refunded after an appeal.
Cloudflare cost playbook
A community playbook for Cloudflare cost retrospectives, cost models, and code review.
Jason Silberman: an approximately $1,000 AI-billing dispute, later reported resolved.
@_jasonsilberman reports an invoice around $1,000 with AI usage rows he says were duplicated and already prepaid. Cloudflare personnel reply, including Matthew Prince, who says the case was escalated. The author later says the issue was resolved.