# Core Concepts

The Grid is a real-time spot market for AI inference - a single venue where developers buy standardized inference capacity from competing suppliers through an OpenAI-compatible API. \
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The system is built on a few fundamental ideas: standardized contracts called Instruments that define quality guarantees, atomic quantities called Units that you trade and consume, and a dual-account system that separates financial ownership from active usage.

* [**Instruments**](https://thegrid.ai/docs/introduction/core-concepts/instruments) - Describes the standardized contracts that guarantee a minimum intelligence, latency, throughput, and context window for delivered inference. 
* [**Units**](https://thegrid.ai/docs/introduction/core-concepts/units) **-** Explains the atomic 1M-token building block of capacity that you trade on the exchange and consume through the API. 
* [**Trading and Consumption Accounts**](https://thegrid.ai/docs/introduction/core-concepts/trading-and-consumption-accounts) - Explains how The Grid separates financial ownership from active usage through two logical balances per Instrument. 
* [**Lots and the Consumption Window** ](https://thegrid.ai/docs/introduction/core-concepts/lots-and-consumption-window)- Describes how Units are grouped into Lots with a four-hour use-it-or-lose-it window that enforces market discipline. 
* \[COMING SOON] [**Scheduled Sweeps**](https://thegrid.ai/docs/introduction/core-concepts/scheduled-sweeps) - Explains the every-four-hour process that automatically moves Units from Trading to Consumption and tightly links trading to delivery. 
* [**Tokens and Metering**](https://thegrid.ai/docs/introduction/core-concepts/tokens-and-metering) - Describes how every API call is tokenized, attributed to specific Lots and Units, and recorded for accurate billing and quality enforcement.
* [**Market Participants**](https://thegrid.ai/docs/introduction/core-concepts/market-participants) – Introduces Consumers, Suppliers, and The Grid Market and how each role participates in trading and delivery.