Free betaFor builders running AI agents on OpenAI, Anthropic and OpenRouter
Find out about a runaway AI bill from us, not from your invoice.
KeyBark watches your API spend from our servers and flags it when an agent loop or a leaked key starts burning money. Alerts show on your dashboard today; email alerts are coming soon. Optional kill switch (beta). No proxy, no SDK, no browser tab to keep open.
Free plan covers one key. No card needed.
This keeps happening
Real posts from builders in the last few weeks. Click through to read them.
Anthropic bill from an agent stuck in a recursive grep loop for 9 hours
Source (opens in a new tab)of Anthropic credits burnt overnight
Source (opens in a new tab)bills reported after the OpenCode key breach
Source (opens in a new tab)API bill from an infinite loop in a CSS file
Source (opens in a new tab)of charges an hour after setting a $30 OpenAI spend limit (Hacker News)
Source (opens in a new tab)- OpenAI spend alerts only notify; a cap needs “Enforce a hard limit”.
- Anthropic can’t cap the Default Workspace.
How it works
→ 1. Connect a key
Paste an OpenAI Admin key, an Anthropic Admin key or an OpenRouter key. We validate it against the provider and encrypt it before storing it.
→ 2. Set your thresholds
Pick a daily and a monthly dollar threshold and turn on spike alerts (today vs. your 7-day average).
→ 3. Get warned (or stopped)
When a threshold is crossed, an alert appears on your dashboard (email alerts are coming soon). If you opted in to the kill switch (beta), KeyBark also disables the key you named through the provider's API.
Checks run about every 15 minutes during the beta, plus on demand with “Check now”. Supported today: OpenAI (organization Costs API), Anthropic (Admin cost report) and OpenRouter (key usage). Integrations are marked beta until they have been verified against many real accounts.
Built like we hold your keys, because we do
Alert-only by default
New keys are only read. Nothing is ever disabled unless you turn on the kill switch for that key.
Encrypted at rest
Provider keys are encrypted with AES-256-GCM before storage. The encryption key lives in a server environment variable, never in the browser or the code repository.
Least privilege
Use the narrowest key the provider offers. You can delete a key from KeyBark at any time, and the encrypted copy is deleted with it.
No proxy
Your production traffic never passes through us. We only call the providers' billing and key-management endpoints.
Pricing
Start free with one key. Upgrade when you have more keys to watch or want the kill switch (beta).
One key, watched for you.
- 1 provider key (OpenAI, Anthropic or OpenRouter)
- Daily, monthly and spike alerts on your dashboard (email alerts coming soon)
- 30-day spend chart
- Free limit audit + leak response plan
For solo builders running agents.
- Up to 3 provider keys
- Everything in Free
- Opt-in kill switch (beta; not yet tested on live provider accounts)
For small teams with several projects.
- Up to 15 provider keys
- Everything in Indie
- Project or client label on each key
For agencies managing client keys.
- Up to 50 provider keys
- Everything in Pro
- Client labels on every key and alert
KeyBark is in beta. Prices in USD per month, billed monthly in advance through Stripe until you cancel. Cancel any time from the Stripe billing portal; your plan stays active until the end of the period you paid for. Alerts show on your dashboard for now; email alerts are coming soon. By subscribing you agree to our Terms and Privacy Policy. On our roadmap (not available yet): Slack, Telegram and SMS alerts, breach mode, faster polling.
FAQ
Doesn't OpenAI already have spend limits?
It has two different things. A spend alert only sends a notification and traffic continues. A hard limit stops traffic only if you turn on “Enforce a hard limit”, and OpenAI says enforcement is not instantaneous. KeyBark adds an independent watcher on top, plus alerts for spikes, and helps you check your settings with the free limit audit.
What about Anthropic?
Anthropic lets you set spend limits per workspace, but not on the Default Workspace. Its usage and cost data usually appears within about 5 minutes. KeyBark reads the Admin cost report and alerts on your thresholds, including Default Workspace spend.
What key do I give you?
For OpenAI, an Admin key (it can read organization costs). For Anthropic, an Admin API key (organization accounts only). For OpenRouter, the API key you want to watch, or a provisioning key plus the target key's hash if you want the kill switch. Use the most limited key the provider allows.
How often do you check?
Right now checks run about every 15 minutes during the beta, plus on demand with “Check now”. Provider cost data also lags (Anthropic says about 5 minutes; OpenAI's cost data is reported in daily buckets), so KeyBark is an early-warning system, not a real-time firewall.
Will the kill switch take my app down?
Only if you turn it on. It is off by default, needs an explicit confirmation, and only fires when a daily or monthly threshold you set is crossed. It is in beta: test it on a non-production key first. Spike alerts never trigger it.
Do you send alerts by email?
Not yet. Email delivery is being set up; until then every alert is recorded on your dashboard under “Recent alerts”. We'll update this page when email alerts are live.
Do I need to install anything?
No. There is no proxy, SDK or browser extension. KeyBark talks to the providers' billing APIs from our servers, so nothing has to stay open on your laptop.