> For the complete documentation index, see [llms.txt](https://docs.lumia.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.lumia.org/build-on-lumia/cdk-repositories.md).

# CDK repositories

You want to know what source repositories Lumia's chain is actually built from, and which parts are Lumia-specific versus stock Polygon CDK.

**Who this is for:** developers or infrastructure engineers who need to read, audit, or build against the underlying stack rather than just use the public RPC. **Prerequisites:** [Lumia's chain framework and settlement](https://app.gitbook.com/s/chmhPiVNAafGw48c4oU2/ecosystem/lumia/architecture/polygon-cdk-and-agglayer/the-lumia-chain-framework-and-settlement) (concept: read this first for what CDK and AggLayer are on Lumia). **Time:** reference lookup, not a task with a fixed duration.

### Architecture

Lumia Prism, the name [`/reference/contract-addresses`](https://app.gitbook.com/s/chmhPiVNAafGw48c4oU2/reference/contract-addresses) uses for Lumia's mainnet, is built on **Polygon CDK** as a zkEVM validium-model L2, settling through Polygon's shared **AggLayer** (see [`/lumia/architecture/polygon`](https://app.gitbook.com/s/chmhPiVNAafGw48c4oU2/ecosystem/lumia/architecture/polygon-cdk-and-agglayer/the-lumia-chain-framework-and-settlement) and [`/lumia/architecture/polygon/agglayer`](https://app.gitbook.com/s/chmhPiVNAafGw48c4oU2/ecosystem/lumia/architecture/polygon-cdk-and-agglayer/how-lumia-settles-and-bridges-to-ethereum)). Polygon CDK's core repositories are public open-source infrastructure maintained by Polygon, not Lumia-specific.

### In the meantime

For the settlement-layer contract addresses that are confirmed (not source repos, but on-chain addresses), see [`/reference/contract-addresses`](https://app.gitbook.com/s/chmhPiVNAafGw48c4oU2/reference/contract-addresses). For what CDK and AggLayer give Lumia conceptually, see [`/lumia/architecture/polygon`](https://app.gitbook.com/s/chmhPiVNAafGw48c4oU2/ecosystem/lumia/architecture/polygon-cdk-and-agglayer/the-lumia-chain-framework-and-settlement).