AI reference

Clear AI definitions and model data you can check.

A glossary written for practitioners, research summaries, and language models compared on price, limits and capabilities, with a source and a date next to every number.

255glossary terms
185articles
65models priced
next-token-prediction.py

Glossary

255 terms · A–Z

Definitions first, then how it works, worked examples, formulas and code.

LLM API pricing

65 models · 5 vendors

Per-token prices from each vendor's own page, with cache, batch and long-context rates.

Models

10 model cards · 9 comparisons

Context windows, limits and capabilities, with the source behind each value.

Tools

Token counter · cost calculator

Count the tokens in your prompt, then see what a month of traffic costs on every model.

LLM changelog

27 changes · last Oct 14, 2026

Model launches, price changes and retirements, each linked to the vendor's notice.

News and research

185 articles

Pricing news, research summaries and applied machine learning explainers.

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Fresh in the reference

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AI Education

Best Open-Source LLMs in 2026: The Top Open-Weight Models Compared

The best open source LLM in October 2026 is no longer a cheap stand-in for a closed model. Epoch AI estimates that the strongest open-weight models trail the closed frontier by about four months, and Stanford's AI Index 2026 measured a…