Some of your customers cost more than they pay.

Waterline connects your model spend to your Stripe revenue and shows gross margin for every customer account. Not estimates. Your invoices, your books, reconciled.

Calculate your margin →

Works with OpenAI, Anthropic and Google. Reads Stripe with a read-only key. We never see your prompts.

The problem

52%

median AI gross margin

ICONIQ State of AI, Jan 2026 (n≈300 software executives)

23%

of revenue: average spend on inference

ICONIQ State of AI, Jan 2026

70%

of AI companies say delivery costs are eroding margins

Revenera Monetization Monitor (n=501 product leaders)

Your provider dashboard shows one number for the whole month. Stripe shows what came in. Nothing connects them, so the question “is this account making us money?” has no answer. And the accounts quietly losing money look exactly like the ones that aren't.

Illustrative example, not measured data. Every account below the line still shows up the same in a blended average.

Process

How it works

01~30 seconds
Connect Stripe
A read-only restricted key. We read customers, subscriptions and charges. Never card data.
02~1 minute
Connect your model providers
OpenAI, Anthropic, Google. Keys encrypted at rest with AES-256. Gets you spend by model immediately.
03~15 minutes of engineering
Tag your calls with a customer ID
One line after each model call. This is the step that turns a total into a per-account number, and it's the one that needs a developer.

The product

What you get

One list, every account, sorted by what it's actually worth to you.

AccountGross margin

acct_7f2a91-34%

acct_9c31e0-12%

acct_2b4188-3%

The waterline

acct_58e014+8%

acct_14f9c2+41%

acct_88a0d5+63%

Illustrative preview, not real data. 3 of 6 accounts shown are below the waterline.

Which accounts are below the waterline?

Gross margin per customer, sorted worst first.

Is our free tier sinking us?

Cost by pricing tier, so you can see what unpaid usage actually costs.

Which feature is eating the budget?

Cost by feature, so gating and bundling decisions have a number behind them.

Did an account just go runaway?

Alerts when an account's cost crosses a threshold or its margin drops sharply, before the invoice arrives.

Get access

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