iOS apps for tracking AI API spend, compared
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Four questions decide this, and only one of them is about features. Rather than ranking apps whose feature sets change monthly, here is what to actually check — and where TKN sits, stated plainly.
The four questions
1. How many providers, and does it combine them?
The whole reason to use a third-party app rather than a provider console is that no provider will show you another provider's number.
An app covering one provider is a nicer console. An app covering four and giving you one figure is doing the thing you can't do yourself. Check whether it presents a combined total or just four separate screens.
Also check whether Gemini is included, and how. Gemini has no simple key path to billing data — it needs Google Cloud Billing. Apps that support it properly have done real work; apps that list it may just have a placeholder.
2. Where does it store your key?
The most important question, and the one least often answered clearly.
Strong: stored in the iOS Keychain, device-only, excluded from iCloud backup, behind biometric lock, never transmitted. If the vendor is breached, your key isn't in the breach because it was never on their servers.
Acceptable: server-side, encrypted at rest, with a stated key-management model.
Weak: server-side, unexplained. If an app can't tell you, assume the worst.
Remember what an admin key can do: read all your billing data and delete every API key in the organisation. That's the blast radius you're placing. Is it safe to give an app your admin key?
A practical check: paste a key with the device in airplane mode. If the app can still display it back to you afterwards and never needed the network, that's a good sign.
3. Does it alert, or only display?
A dashboard you must open has the same failure mode as the provider console: nobody opens it on a normal Tuesday.
Look for a threshold you set, evaluated against daily spend rather than a monthly budget percentage. A monthly-cumulative alert won't tell you that today cost 20× normal — getting alerted when AI spend spikes covers why that distinction matters.
4. Can it act?
Most can't. They show you a number and the response is still: open a laptop, find the console, sign in, locate the key, delete it.
An app that can revoke at the provider closes that gap. It's the difference between knowing at the weekend and being able to do something at the weekend.
Two different categories
Worth not confusing:
Metered API spend trackers read provider billing APIs. They cover pay-per-token usage on OpenAI, Anthropic, xAI and Google. TKN is one of these.
Subscription quota trackers watch plan usage windows — Claude Code, Codex and similar — by reading local session logs or plan quota. Different data source, different question.
If you're on a Max or Pro plan rather than metered API billing, an API spend tracker will show you nothing, because there's no metered spend to show. Check which one you need before installing.
Where TKN sits
Since this is TKN's site:
- Providers: OpenAI, Anthropic, xAI (Grok), Google Gemini — one combined figure with a per-provider and per-model breakdown
- Key storage: iOS Keychain, Secure Enclave-backed, device-only, non-iCloud, behind Face ID. Never uploaded. Open source, so this is checkable
- Alerts: spend rules evaluated against live daily spend
- Action: a kill switch that calls the provider's own key-management API — one key, one provider, or all
- Also: a CLI and an MCP server on the same data
What it does not do: real-time figures (it reads billing APIs, which are daily), per-request or per-customer attribution, or subscription plan quota tracking. If you need any of those, TKN is the wrong tool and the comparison page says which is right.