If you wanna build apps on the blockchain, you are likely going to need a way to query data.

We just published a course on the freeCodeCamp.org YouTube channel that will teach you how to query data on the blockchain in order to build your own decentralized apps.

Ania Kubów developed this course. She is a popular instructor who has created amazing courses on a variety of programming topics.

This course is all about querying data on Web3 decentralized applications. You will get an introduction to indexing and querying data on the Ethereum blockchain. Querying data on decentralized networks is very different than what you may be used to on the traditional web.

By the end of this course you will have the knowledge to query data from the Ethereum mainnet as well as a variety of other chains in order to build you own decentralized apps.

You will learn how to use The Graph. It is an indexing protocol for querying networks like Ethereum and IPFS. Anyone can build and publish open APIs, called subgraphs, making data more easily accessible.

This course was made possible through a grant from The Graph.

Here are the sections covered in this course:

  • What we will cover
  • What is The Graph for?
  • Subgraphs
  • Subgraph manifests
  • Why build a subgraph?
  • Let’s build a subgraph!
  • Querying from a frontend
  • API key management

Watch the full course below or on the freeCodeCamp.org YouTube channel (1-hour watch).