If you are an AI Engineer, you likely use third-party APIs like OpenAI, Anthropic, or Pinecone. If you are paying for these out of pocket, you are losing money every second.
1. The 'Reimbursable' Strategy
Your contract should state: "Client is responsible for all third-party software and API licensing costs incurred during the project."
2. Invoicing the Markup
It is standard practice to add a 10-20% Administrative Markup when you pay for these services on behalf of the client. This covers the cost of you managing the billing and the currency exchange risks.
- API Cost: $100
- Admin Fee (15%): $15
- Total Line Item: $115
3. Transparency is Key
Always provide the original receipts as an attachment to your professional invoice.
🛑 Privacy Warning
Receipts often contain your personal credit card info or address. Use DocuFix.in to format and prepare your receipt attachments locally without uploading them to a random server.
Frequently Asked Questions (FAQ)
Should I put the client's credit card on the API account?
Yes. This is the best long-term solution. It ensures the service isn't cut off if you stop working together and keeps your invoicing clean.
What if I use my own 'Enterprise' license?
If you are providing access to a tool you already pay for, bill it as a "Seat License Fee" rather than a reimbursement.
How do I handle 'Usage-Based' billing?
Estimate the monthly cost in your proforma invoice and bill the actuals at the end of every month.