> For the complete documentation index, see [llms.txt](https://docs.talentlayer.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.talentlayer.org/technical-guides/lower-level-guides/graph-schema/introduction.md).

# Introduction

## Exploring the Subgraph

### Subgraph link

* [**Polygon Mumbai Testnet**](https://api.thegraph.com/subgraphs/name/talentlayer/talent-layer-mumbai)
* [**Polygon mainnet**](https://api.thegraph.com/subgraphs/name/talentlayer/talentlayer-polygon)

### Playground Link

{% hint style="info" %}
To ensure that your queries are working properly before using them in your project, you can use the Graph playground below.
{% endhint %}

* [**Polygon Mumbai playground**](https://thegraph.com/hosted-service/subgraph/talentlayer/talent-layer-mumbai)
* [**Polygon mainnet pLayground**](https://thegraph.com/hosted-service/subgraph/talentlayer/talentlayer-polygon)

Please check the demo video just below\
[how to test queries with The Graph Playground](https://loom.com/share/a95f65ebe9da4bd1908ca6aacf0b765b)

{% hint style="info" %}
Using the playground, you can create and save your own graphQL queries and try out the default queries **we provide to get you up and running!**
{% endhint %}

<figure><img src="/files/sqtw3Qg4HhwWa6Ck7zfh" alt=""><figcaption></figcaption></figure>

{% hint style="info" %}
On the right-hand side, you have access to some neat functionality that will help you explore the subgraph. Check out **GraphQL Explorer** as well as **Documentation Explorer** to create customized queries on the fly!
{% endhint %}

<figure><img src="/files/ndwt9q4MRVMfWxP29dfU" alt=""><figcaption></figcaption></figure>

### **An Introduction to Writing GraphQL Queries for the Talent Layer Subgraph**

The most commonly used entities have a related description entity that stores the off-chain data hosted on [IPFS](https://www.ipfs.com/).

| On-chain Entity | Off-chain Entity    |
| --------------- | ------------------- |
| Service         | ServiceDescription  |
| Proposal        | ProposalDescription |
| Review          | ReviewDescription   |
| User            | UserDescription     |
| Platform        | PlatformDescription |

The off-chain entity that is related to an on-chain entity can be accessed through the field description. Here is an example of what the relationship looks like in GraphQL.

```graphql
{
  services {
    id
    description {
      id
    }
  }
}gr
```

{% hint style="info" %}
This same pattern can be applied to other entities by simply changing **services** to either **users, proposals, reviews,** or **platforms.**
{% endhint %}


---

# Agent Instructions
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## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.talentlayer.org/technical-guides/lower-level-guides/graph-schema/introduction.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

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Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.