OpenAI cost P&L is cost versus what that customer pays.

OpenAI sends one invoice. Finance cannot raise a price from a company total. A customer P&L is a different noun. It puts OpenAI cost next to the plan price you charge that customer. The row is this month. The sign is plus or minus. Sample acme-health is −101%. That is the product.

CostSlice is that report. We are a pass-through OpenAI proxy plus the customer P&L. You keep your OpenAI API key. An engineer changes the OpenAI address to https://api.costslice.com/v1 and sends x-cs-key, x-cs-tenant, x-cs-feature, x-cs-env. We count. You read cost versus what they pay.

We report. We do not cap the tenant because the row is red. Unprofitable is a fact on the page, not a kill switch. Humans raise a price, trim a window, or leave the customer alone. Starter is a hard cap on the CostSlice plan — 10,000 requests, no overage — not a cap on acme-health.

The OpenAI usage dashboard cannot do this job. It is the org bill. The Costs API can group by project, API key, and a user label. That label is not your invoice. One project per client works until you have fifty customers. A wrapper in your process can count tokens. It still is not a P&L next to plan price.

Plan price is the number you already charge. Paste it on the customer. The P&L subtracts OpenAI cost. Margin is the rest. If you have not set a price yet, the row still shows cost. That is enough to see who is expensive. Setting the price turns cost into a statement finance will sit with.

Feature names belong on the same request. Chat, summaries, and copilot do not cost the same. A summary that fires on every ticket can sink a customer who looks fine at the account level. The P&L splits the row. See OpenAI spend per feature.

How teams get here: they try the user field, then a project per client, then a spreadsheet. The playbook is track OpenAI cost by customer. This page is the finance noun at the end of that playbook.

The sample is not live traffic. Same shape a new workspace starts with. Two customers unprofitable. $2,490 over plan this month. acme-health clinical summaries is the red row. See the sample P&L.

Retention is the window you can still read. Starter keeps seven days. That is enough to see this month if you look this week. Pro keeps 90 days. Scale keeps a year. Export CSV when you need the file in a sheet.

Keys stay in your product. We never store the OpenAI API key. Authorization is forwarded. We never log it. x-cs-key is a CostSlice credential. We store a hash so we can look up the workspace. We do not email that secret again.

Missing tags do not drop the completion. Untagged still returns. Fix the header on the next call. We would rather show a messy row than take down chat. That is ingest. It is not a promise that the proxy cannot fail.

Claude is not on this product today. OpenAI only. Other models come later. If you already route elsewhere, keep that box. CostSlice still only sits in front of OpenAI.

Starter $0 / Pro $79 / Scale $199, overage $6/100k. No credit card on Starter. Pricing on the homepage wins if a number here is stale. There is no /pricing URL.