AI inference glossary
Model architecture

Tokenization

Also known as tokenizer, token, byte pair encoding, BPE

In plain English

Tokenization splits text into the sub word units a model actually reads and writes, and every performance and price number is quoted in them.

Technical definition

Tokenization is the conversion between text and the discrete token IDs a model processes, using a fixed vocabulary learned with methods such as byte pair encoding.

Engineering details

A tokenizer maps common words to single tokens and rarer strings to several, with English averaging very roughly four characters per token. Vocabularies differ between model families, so identical text can produce meaningfully different token counts across models. Everything downstream is denominated in tokens: context windows, KV cache size, throughput, latency per token, and price per million tokens all count these units, not characters or words.

Why it matters

Token efficiency is a hidden price lever, since a model that needs fewer tokens for the same content is cheaper at an identical per token rate. Comparing providers or benchmarks without normalizing for tokenizer differences quietly distorts cost and speed conclusions.

How to read it in InferenceX

InferenceX metrics are token denominated, and its AgentX traces replace original text with deterministic synthetic tokens while preserving per turn token counts, so replayed sessions stress serving systems with the same token arithmetic as the source workload.