> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lumenaza.de/llms.txt
> Use this file to discover all available pages before exploring further.

# Lumenaza API Key Concepts: Customers, Contracts, Tariffs

> Learn how Lumenaza models energy customers, contracts, market locations, and tariffs for the German energy market.

The Lumenaza API is built around a clear hierarchy: a **tenant** (your organisation) manages end-customers — **consumers** and **producers** — each of whom holds one or more **contracts** for energy delivery or feed-in. Every contract is tied to a physical supply point identified by a **Market Location (MaLo)** in the German grid, and is priced by a **product** (tariff plan). Understanding how these entities relate to one another is the foundation for working with the API effectively.

The sections below introduce each concept in detail. Use the cards to navigate to the topic you need.

<CardGroup cols={2}>
  <Card title="Consumers & Producers" icon="users" href="/concepts/consumers-and-producers">
    Learn about the two types of customers — electricity buyers and renewable energy plant operators — including prosumers who act as both.
  </Card>

  <Card title="Contracts" icon="file-contract" href="/concepts/contracts">
    Understand the energy delivery agreement lifecycle, registration statuses, market locations, meters, and how to terminate or revoke a contract.
  </Card>

  <Card title="Products & Tariffs" icon="tag" href="/concepts/products-and-tariffs">
    Explore how pricing plans are attached to contracts, including validity periods, contract terms, product switches, and the offer calculator.
  </Card>
</CardGroup>

## Data model at a glance

The diagram below shows how the core entities are related.

```text theme={null}
Whitelabel Customer
└── Consumer / Producer (saas_customer_id)
    └── Contract (saas_contract_id)
        ├── Market Location (meteringpoint_id)
        ├── Meter (meter_id)
        └── Product (product_name)
```

<Note>
  Every entity you create in Lumenaza can carry **your own system's identifier** — `saas_customer_id` for customers and `saas_contract_id` for contracts — making it straightforward to reconcile Lumenaza records with your own database.
</Note>


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.