The Graph

Introduction

Getting historical data on a smart contract can be frustrating when you’re building a dApp. The Graph provides an easy and decentralized option to query smart contract data through APIs known as subgraphs. Its infrastructure relies on a decentralized network of indexers, enabling your dApp to achieve true decentralization.

These subgraphs only take a few minutes to set up. To get started, follow these three steps:

All developers receive 100k free queries per month on the decentralized network. After these free queries, you only pay based on usage at $4 for every 100k queries.

1. Initialize Your Subgraph Project

Create a Subgraph on Subgraph Studio⁠

Go to the Subgraph Studio and connect your wallet. Once your wallet is connected, you can begin by clicking Create a Subgraph. When choosing a name for your subgraph, it is recommended to use title case, e.g. “Subgraph Name Chain Name.”

You will then land on your subgraph’s page. All the CLI commands you need will be visible on the right side of the page:

Install the Graph CLI⁠

On your local machine run the following:

npm install -g @graphprotocol/graph-cli

Initialize your Subgraph⁠

You can copy this directly from your subgraph page to include your specific subgraph slug:

graph init --studio <SUBGRAPH_SLUG>

You’ll be prompted to provide some info on your subgraph like this:

Simply have your contract verified on the block explorer and the CLI will automatically obtain the ABI and set up your subgraph. The default settings will generate an entity for each event.

2. Deploy and Publish

Deploy to Subgraph Studio⁠

First, run these commands:

$ graph codegen
$ graph build

Then run these to authenticate and deploy your subgraph. You can copy these commands directly from your subgraph’s page in Studio to include your specific deploy key and subgraph slug:

$ graph auth --studio <DEPLOY_KEY>
$ graph deploy --studio <SUBGRAPH_SLUG>

You will be asked for a version label. You can enter something like v0.0.1, but you’re free to choose the format.

Test Your Subgraph⁠

You can test your subgraph by making a sample query in the playground section. The Details tab will show you an API endpoint. You can use that endpoint to test from your dApp.

Publish Your Subgraph to The Graph’s Decentralized Network

Once your subgraph is ready to be put into production, you can publish it to the decentralized network. On your subgraph’s page in Subgraph Studio, click on the Publish button:

Before you can query your subgraph, Indexers need to begin serving queries on it. To streamline this process, you can curate your own subgraph using GRT.

When publishing, you’ll see the option to curate your subgraph. As of May 2024, it is recommended that you curate your own subgraph with at least 3,000 GRT to ensure that it is indexed and available for querying as soon as possible.

3. Query Your Subgraph

Congratulations! You can now query your subgraph on the decentralized network!

For any subgraph on the decentralized network, you can start querying it by passing a GraphQL query into the subgraph’s query URL which can be found at the top of its Explorer page.

Here’s an example from the CryptoPunks Ethereum subgraph by Messari:

The query URL for this subgraph is:

https://gateway-arbitrum.network.thegraph.com/api/**[api-key]**/subgraphs/id/HdVdERFUe8h61vm2fDyycHgxjsde5PbB832NHgJfZNqK

Now, you simply need to fill in your own API Key to start sending GraphQL queries to this endpoint.

Getting Your Own API Key

In Subgraph Studio, you’ll see the API Keys menu at the top of the page. Here you can create API Keys.

Appendix

Sample Query

This query shows the most expensive CryptoPunks sold:

{
  trades(orderBy: priceETH, orderDirection: desc) {
    priceETH
    tokenId
  }
}

Passing this into the query URL returns this result:

{
  "data": {
    "trades": [
      {
        "priceETH": "124457.067524886018255505",
        "tokenId": "9998"
      },
      {
        "priceETH": "8000",
        "tokenId": "5822"
      },
//      ...

Trivia: Looking at the top sales on the CryptoPunks website, it looks like the top sale is Punk #5822, not #9998. Why? Because they censor the flash-loan sale that happened.

Sample Code

const axios = require('axios');

const graphqlQuery = `{
  trades(orderBy: priceETH, orderDirection: desc) {
    priceETH
    tokenId
  }
}`;
const queryUrl = '<https://gateway-arbitrum.network.thegraph.com/api/[api-key]/subgraphs/id/HdVdERFUe8h61vm2fDyycHgxjsde5PbB832NHgJfZNqK>'

const graphQLRequest = {
  method: 'post',
  url: queryUrl,
  data: {
    query: graphqlQuery,
  },
};

// Send the GraphQL query
axios(graphQLRequest)
  .then((response) => {
    // Handle the response here
    const data = response.data.data
    console.log(data)

  })
  .catch((error) => {
    // Handle any errors
    console.error(error);
  });

Additional Resources:

To explore all the ways you can optimize and customize your subgraph for better performance, read more about creating a subgraph here.
For more information about querying data from your subgraph, read more here.

Images used in this article are sourced from The Graph.

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