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LLM Engineering

What is Token?

The billing and budgeting atom of language models: text is split into subword pieces and every input, cached, thinking, and output token is metered separately. BYOB counts tokens with tiktoken and converts usage into credits per model pricing.

Example

A BYOB chat turn records input, cached, thinking, and output tokens separately, then prices each leg from the active model config — the same counters that feed the token meter and credit billing.

What people get wrong

Treating one token as one word or one character. Subword splitting means code and non-English text cost more tokens per character than plain English prose.

Frequently asked questions

Why do identical prompts cost different credits on different models?

Each model config carries its own input, output, cached, and thinking prices, so the same tokens convert to different credit amounts per model.

Do cached tokens still cost anything?

Yes, at a reduced cached rate — reuse lowers the bill instead of removing it.

Sources

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