# Introduction

<mark style="color:red;background-color:yellow;">**This guidebook will be deprecated soon!**</mark>&#x20;

<mark style="color:purple;">**Please refer to this newly improved CoinGecko API documentation:**</mark> [<mark style="color:purple;">**https://docs.coingecko.com/**</mark>](https://docs.coingecko.com/)&#x20;

[CoinGecko API](https://www.coingecko.com/en/api) provides the most comprehensive & reliable crypto data through **RESTful JSON** endpoints. Thousands of forward-thinking projects, Web3 developers, researchers, institutions, and enterprises use our API to obtain price feeds, market data, metadata, and historical data of crypto assets, NFTs, and exchanges.

Here are some of the common use cases for clients who use CoinGecko API:

* Crypto Exchanges (CEX, DEX), Trading Apps
* Wallets (Hot, Cold）
* Data Aggregator, Crypto Screener, Analytics Dashboard
* Block Explorer, Portfolio Tracker
* DeFi Protocols, NFT Marketplaces, Digital Bank
* Backtesting Trading Strategy
* Accounting, Tax, Audit, HR Payroll
* Research & Analysis: Media, Institution, Academic, VC, Financial
* Oracles, Bots, Payments, E-commerce, and more!

You may try out most of the endpoints with our public API swagger doc: <https://www.coingecko.com/en/api/documentation>

Other exclusive endpoints for paid plan users are listed on the [Exclusive Endpoints](https://coingecko-api.gitbook.io/coingecko-api-guide/exclusive-endpoints/pro-api) page.

The Public API is mainly used for testing & non-commercial hobby usage. For serious research and project development work, you should use our Pro API for reliable performance, higher rate limit, faster data freshness, access to exclusive endpoints, and priority support. You may obtain API key to use Pro API by subscribing to any paid plan here: <https://www.coingecko.com/en/api/pricing>

The next page will guide you on how to get started with API key to access Pro API.


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# Agent Instructions: 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:

```
GET https://coingecko-api.gitbook.io/coingecko-api-guide/getting-started/introduction.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

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.