Your AI bill, split by customer.
MarginCap joins your LLM spend with your Stripe revenue. You see what every customer actually earns you, and you can cap the ones who cost more than they pay.
- Revenue
- $412
- AI cost
- $173.93
- Margin
- 58%
- Losing money
- 2customers, not capped
| Customer | Cap | ||
|---|---|---|---|
| cus_8fK2… | $64.10 | −121% | |
| cus_Q1xa… | $52.80 | −8% | |
| cus_T9ve… | $24.60 | 15% | |
| cus_3mPz… | $18.40 | 81% | |
| cus_Hn42… | $7.90 | 84% | |
| cus_Lr7d… | $2.15 | 93% | |
| cus_Zq5c… | $3.10 | 97% | |
| cus_Wb0e… | $0.88 | 97% |
In development. OpenAI, Anthropic, OpenRouter and Gemini at launch, TypeScript SDK first. The table above runs on example data.
You charge $29 a month.
One customer just used $64 in tokens.
Your OpenAI dashboard can’t tell you which one.
Know who’s profitable. Stop who isn’t.
Revenue minus AI cost for every Stripe customer, the features behind it, and a way to stop the bleeding before the invoice arrives.
agent_loop is 3% of your calls and 66% of your spend.
The SDK runs async, outside your request path. If MarginCap is down, your app doesn’t notice.
Five minutes to set up.
No migration, and no proxy sitting between you and your model provider.
Wrap your client
One line around the SDK you already use.
track(new OpenAI(), { customerId, feature })Connect Stripe
Read-only. We pull revenue per customer and touch nothing else.
Read the table
Every customer’s revenue, AI cost and margin, with the money-losers on top.
Priced for founders, not FinOps teams.
Pay for events, not seats. Every plan includes cost per customer.
Free
- 50k events a month
- Cost per customer
Indie
- 1M events a month
- Stripe margin view
- Email alerts
Startup
- 10M events a month
- Hard caps
- Slack alerts
- Cost per feature
Founding member · first 50
$19/mo on Indie, locked while you stay subscribed.
Limited to the first 50 founding members. US$19/month, charged today and monthly until you cancel; taxes extra where they apply. Full refund on request any time before launch. Launch date to be announced. Pre-order terms
Questions.
How is this different from Langfuse or Helicone?
They’re observability tools. They show what a user cost, but they don’t know what that user pays you. MarginCap joins the two and gives you margin.
Can’t Stripe’s token billing do this?
Stripe token billing helps you charge customers for tokens. If you’re on flat or per-seat pricing, like most of us, it doesn’t show which customers you’re losing money on.
Do I need usage-based pricing?
No. MarginCap is built for flat and per-seat pricing, which is exactly where power users hide.
What if I don’t use Stripe?
You still get cost per customer and hard caps. A CSV revenue import is coming soon.
Who’s building this?
I’m Omar Kamel, a solo developer building MarginCap. Questions? [email protected]
Stop guessing which customers are profitable.
Join the early-access list. One email when it’s ready.