Has an AI tool ever sent you a surprise bill?
I believe that cloud providers should make hard spending caps the default: when you hit your limit, everything stops, rather than you getting a warning email you only see after the damage.
The reason is simple: coding agents can now ship code that burns through paid APIs while you sleep.
AWS and Google Cloud have both added spend caps recently, but they're opt-in.
I see this from the launch side too. A product goes viral on launch day, the free tier gets hammered, and the founder spends the next week looking at the bill instead of the traffic.
Many makers that reach out to me, building with AI have a "wait, how much?" story, and those are fun to tell, but obviously, it's not an ideal situation to be in.
Let me know what you think: Would you rather let your app go down or get a surprise bill? And if it's already happened to you: what did it cost?
P.S. Check out the products I hunted today and offer your feedback:
@FastRouter.ai: Route requests to the right LLM for cost, latency & quality.
@dailyhelm: Turn analytics into daily revenue-boosting fixes.
Replies
My own setup: I’m a Hunter on Product Hunt, but I also build small products for my own use. Most are local, so my main costs are API usage. For most APIs, I preload credits and pay as I go, which keeps any surprise bill limited.
I want to learn from the experience of makers who build serious big SaaS products.
@harsh_jhunjhunuwala @sachinchoolur @harshsaver How do you handle it? :)
I’d probably have the app going down over getting a huge surprise bil. When you’re a small team, an unexpected API or cloud bill can hurt a lot more than a few hours of downtime. Better to deal with downtime than a surprise invoice.
@aruna_polosofttech Completely understand the sentiment. A runaway loop or leaked key or any other issue that goes into a spiral can cause serious issues for a startup. Apart from real time alerts, you can also configure spend limits per day/week/month etc. at a key and project level that will help you avoid spend shocks.
@ritprasad Makes a lot of sense. Having spend limits both at the key level and project level sounds like a practical way to keep things under control, especially for startups. The ability to set daily, weekly, or monthly limits will definitely be useful.
We went prepaid credits on our own product for exactly this reason, there's no overdraft path, so the worst case is someone hits zero and generation stops. Downtime over invoice, every time. The part nobody warns you about is that the cap itself is the fragile bit. We shipped a spend function that was writing bad balance events, so the ledger drifted from reality and the ceiling we thought we had wasn't actually the ceiling. A hard cap you haven't tested at zero is just a number in a config file.
@asadmalik901 This is a great option.
However, some startups also get some free credits via providers. So adding those provider keys via the BYOK feature that FastRouter offers can be a way to access both i.e. the free credits as well as the stored wallet value.
But yes, it is very important to get real time alerts. FastRouter not only sends proactive alerts at a key / project / organization level -- but it also allows you set up custom real time alerts that are threshold and % value based (in comparison to a previous period) and send them to channels such as Slack/PagerDuty. This way, you are on top of issues - be it spend spikes or even issues such as latencies or errors.
What other metrics other than spend caps are important to you? Will be sure to add them if we are not measuring them already.
Absolutely @rohanrecommends
Many providers send you a warning mail when you hit a cap; and the worst thing that can happen is when the mail is sent during a weekend or late night when no one is there to check.
The second issue is that if you don't work with a control plane like FastRouter.ai for governance, you have to set limits in different provider interfaces, each of them being different.
On FastRouter, you can set real time alerts and not just compare them to fixed thresholds but also to % differences from a comparison period from before and have these alerts sent via email or to even tools like Slack and PagerDuty. This way, you get notified of the metrics that matter to you - e.g. latencies, cost spikes, error rates, etc. and in real time.
Other than cost / latency / errors, would love to know what other metrics are key for your apps - would be happy to add them if we are not measuring them already.
@ritprasad Wow, that's an very good feature I had not discovered yet of @FastRouter.ai. It also plugs beautifully to the problem I raised in my forum post. Thanks for chiming in, Ritesh. :)
This exact thing happened to me. Last weekend, I woke up to a notification that a transaction of ₹2,030 had been processed for Google Cloud.
I immediately checked my console and found that for the last 12 days, I had been running 250 GB of persistent disks without any actual use case. The service was enabled by AI during a task, and I hadn’t reviewed it before letting it run.
I deleted the disk right away, but it was a paid lesson in why you shouldn't blindly trust AI. After that, I went through everything else racking up costs, added spending caps, and set up hard limits.