I was paying about $6 a month for Cloudflare R2. Not a lot. But I wasn't doing anything that should cost $6 a month.
I looked into it. The problem was bisync running every 5 minutes.
Every sync cycle generates R2 API calls - Class A operations (writes, lists) and Class B operations (reads). Cloudflare bills per million operations. At 5-minute intervals, that's 288 sync cycles a day. Across multiple agents and directories, the operations add up fast - not because any single sync is expensive, but because the frequency compounds the cost invisibly.
The fix: change the interval from every 5 minutes to every 30 minutes.
Bill went from ~$6 to ~$0.36.
This is the category of problem that's easy to miss because the individual cost looks small. $6 a month doesn't trigger an alert. It doesn't show up in any dashboard that anyone checks. It just quietly runs up because no one thought to ask "how often does this actually need to run?"
The answer, for syncing agent workspaces, is: not every 5 minutes. Nothing urgent lives there. 30 minutes is fine. Probably hourly would be fine.
The lesson isn't really about R2 pricing. It's about interval-based jobs generally. Every recurring task has a frequency that made sense when someone set it up - or more often, a frequency that was never really thought about at all. "Every 5 minutes" is a default that feels safe. It's not always the right call.
If you're running bisync, rclone, or any other sync process on a schedule: check your R2 operation counts in the Cloudflare dashboard. If Class A ops are climbing, interval is usually the first thing to look at.
TL;DR
- Bisync running every 5 minutes = 288 cycles/day = R2 operation costs that compound quietly
- Changing to every 30 minutes cut the bill 94% with zero impact on functionality
- Check the frequency of your recurring jobs - "every 5 minutes" is often a default nobody questioned