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

# What is DeFindex

DeFindex is yield infrastructure. You integrate it once and your users get a balance that earns, without you building or auditing any DeFi yourself.

First, lets define some concepts:

**Yield** is what money earns while it sits somewhere that pays for it. DeFindex does not create yield. It comes from outside: a lending market, an exchange, a tokenized bond.

**A strategy** is code that knows how to earn in one of those places and how to get the money back out. We write each one and have it audited before it ships.

**A vault** is the contract your users deposit into. It holds the money, spreads it across the strategies you picked, and reports back one balance and one APY, which is that yield written as a yearly rate.

## Five layers, and only one holds the money

| Layer                | What it is                                                                                                             | Who controls it                   |
| -------------------- | ---------------------------------------------------------------------------------------------------------------------- | --------------------------------- |
| **You**              | The neobank, fintech or wallet your users see. You own a vault and set its fee                                         | You                               |
| **The API**          | What you integrate against. It builds the transactions your app signs and sends, and reads balances and APY back       | DeFindex                          |
| **The vault**        | The contract holding your users' deposits and spreading them across the strategies you picked. Usually one per partner | You                               |
| **A strategy**       | Code that connects to one yield source and knows how to earn there                                                     | DeFindex, audited before it ships |
| **The yield source** | The outside protocol the return actually comes from: a lending market, an exchange, a tokenized bond                   | Its own team, not DeFindex        |

Only the vault holds money. The two layers above it move instructions, and the two below are where the vault sends money to earn and takes it back.

The bottom layer is the one DeFindex does not own, so its risk is its own. The [audits of those protocols](/advanced-documentation/risks-and-audits) are listed alongside ours.

From your side it is a few API calls. Your app shows one number, your users put money in and take it out whenever they want, and you charge a fee on what the vault earns.