API Credits & AI LLM Billing Explained
Understand the balance. Measure the work. Know the rules.
What are API credits?
API credits are a way to account for eligible service usage. A balance may represent prepaid funds, promotional support, or a platform-defined unit. The issuer decides what it buys. Start by recording the account, covered products, currency or unit, expiration, and deduction rules. Our fundamentals article explains these distinctions with a worked example.
Credits are not tokens
A token measures content under a model’s tokenizer. A credit funds work under a service’s rules. A request is a call that may consume many tokens and other resources. These units cannot be treated as interchangeable, and there is no universal tokens-per-credit conversion across providers.
For illustration only, a fictional model charging $1 per million input tokens and $4 per million output tokens would charge $0.004 for 2,000 input and 500 output tokens. That calculation excludes every other service and is not a current provider price. It simply shows how a monetary balance can be connected to measured usage.
Build the smallest useful budget
Choose a representative task and define an acceptable result. Measure the complete workflow, including follow-up calls and retries. Multiply the observed cost by a realistic activity estimate, and keep uncertain assumptions visible. Record development experiments separately from production usage.
Assign a billing owner and a technical owner. Decide who can buy funds, inspect the account, change reload settings, and pause the application. For a one-person project, these are still separate responsibilities even when one person handles both.
Keep the limits separate
A prepaid balance is not the same control as an automatic reload permission, a rate limit, or an application budget. Verify what each setting actually does. Test the user experience when your own ceiling is reached, and account for work already in progress rather than assuming every limit stops all charges instantly.
Choose your next step
Read the provider guides for account-specific questions. Compare offers using the cost-control framework. Explore free allowances and startup awards separately. When an offer uses blockchain or transferable-token language, begin with the tokenized credit checklist and the issuer’s actual terms.
Provider facts are supported by the official source directory. The glossary defines the 25 terms used across these guides.