> ## Documentation Index > Fetch the complete documentation index at: https://protocol.crunchdao.com/llms.txt > Use this file to discover all available pages before exploring further. # Crunch Protocol > The on-chain and off-chain architecture that connects Coordinators with ML engineers to solve prediction challenges. The Crunch Protocol is the infrastructure layer that enables secure, scalable crowdsourcing of predictive models. It combines on-chain smart contracts with off-chain compute nodes to coordinate a global network of ML contributors. This section explains the protocol architecture in depth. If you'd rather start building, jump to the [Getting started](/getting-started/local-environment-setup) guide. ## Architecture overview The protocol consists of two layers working together: * **On-chain** — Solana smart contracts that handle Coordinator registration, competition lifecycle, reward escrow, and payout distribution * **Off-chain** — Crunch Nodes and Model Nodes that handle data, model execution, scoring, and reporting Diagram showing the Crunch Protocol with on-chain contracts connecting Coordinators and Crunchers to off-chain Crunch Nodes and Model Nodes ## Crunches A **Crunch** is the protocol's core unit: a prediction challenge with defined rules, inputs, and expected outputs. Every interaction in the protocol happens within the context of a Crunch. Each Crunch: * **Locks rewards** — USDC is escrowed in a smart contract before the competition starts * **Defines rules** — evaluation criteria, duration, payout schedule, and model constraints * **Enforces quality** — models are continuously evaluated against real-world outcomes and secondary metrics such as latency and stability * **Sets resource limits** — maximum GPU time, RAM, external-resource access, and minimum performance thresholds ## Participants Crunches bring together two groups: ### Crunchers Machine learning engineers who develop and submit models. They earn rewards based on prediction quality — measured against the rules and metrics the Coordinator defines. Crunchers compete independently, and the best-performing models rise to the top of the leaderboard. ### Coordinators Domain-expert teams who design and operate Crunches. As a Coordinator, you: * Run an **on-chain Coordinator account** registered with the protocol * Operate a **Crunch Node** that manages data, triggers inference, scores predictions, and generates leaderboards * Distribute **rewards** via smart-contract checkpoints based on model performance Diagram showing the Crunch workflow: Coordinator provides data, models predict, scores are computed, and rewards are distributed on-chain ## Emissions The protocol supports two reward mechanisms: * **USDC payouts** — funded by the Coordinator's escrowed prize pool * **CRNCH token emissions** — protocol-level token rewards In both cases, the Coordinator triggers **checkpoints** that distribute rewards on-chain. Participants then claim their earnings through the [Tournament Hub](https://hub.crunchdao.com/). Diagram showing how checkpoints trigger on-chain reward distribution and how participants claim their rewards ## What's next The following pages explain each component of the protocol in detail: The services you build and host to run your competition. The managed infrastructure that executes participant models.