Building Subgraphs on Base

This guide will quickly take you through how to initialize, create, and deploy your subgraph on Base testnet.

What you'll need:

• A Base testnet contract address
• A crypto wallet (e.g. MetaMask or Coinbase Wallet)

Subgraph Studio#Link to this section

1. Install the Graph CLI#Link to this section

The Graph CLI (>=v0.41.0) is written in JavaScript and you will need to have either npm or yarn installed to use it.

# NPM
npm install -g @graphprotocol/graph-cli

# Yarn
yarn global add @graphprotocol/graph-cli

2. Create your subgraph in the Subgraph Studio#Link to this section

Go to the Subgraph Studio and connect your crypto wallet.

Once connected, click "Create a Subgraph" and enter a name for your subgraph.

Select "Base (testnet)" as the indexed blockchain and click Create Subgraph.

3. Initialize your Subgraph#Link to this section

You can find specific commands for your subgraph in the Subgraph Studio.

Make sure that the graph-cli is updated to latest (above 0.41.0)

graph --version

Initialize your subgraph from an existing contract.

graph init --studio <SUBGRAPH_SLUG>

Your subgraph slug is an identifier for your subgraph. The CLI tool will walk you through the steps for creating a subgraph, including:

• Protocol: ethereum
• Subgraph slug: <SUBGRAPH_SLUG>
• Directory to create the subgraph in: <SUBGRAPH_SLUG>
• Ethereum network: base-testnet _ Contract address: <CONTRACT_ADDRESS>
• Start block (optional)
• Contract name: <CONTRACT_NAME>
• Yes/no to indexing events (yes means your subgraph will be bootstrapped with entities in the schema and simple mappings for emitted events)

3. Write your Subgraph#Link to this section

If emitted events are the only thing you want to index, then no additional work is required, and you can skip to the next step.

The previous command creates a scaffold subgraph that you can use as a starting point for building your subgraph. When making changes to the subgraph, you will mainly work with three files:

• Manifest (subgraph.yaml) - The manifest defines what datasources your subgraphs will index. Make sure to add base-testnet as the network name in manifest file to deploy your subgraph on Base testnet.
• Schema (schema.graphql) - The GraphQL schema defines what data you wish to retreive from the subgraph.
• AssemblyScript Mappings (mapping.ts) - This is the code that translates data from your datasources to the entities defined in the schema.

If you want to index additional data, you will need extend the manifest, schema and mappings.

For more information on how to write your subgraph, see Creating a Subgraph.

4. Deploy to the Subgraph Studio#Link to this section

Before you can deploy your subgraph, you will need to authenticate with the Subgraph Studio. You can do this by running the following command:

Authenticate the subgraph on studio

graph auth --studio <DEPLOY_KEY>

Next, enter your subgraph's directory.

cd <SUBGRAPH_DIRECTORY>

Build your subgraph with the following command:

graph codegen && graph build

Finally, you can deploy your subgraph using this command:

graph deploy --studio <SUBGRAPH_SLUG>

5. Query your subgraph#Link to this section

Once your subgraph is deployed, you can query it from your dapp using the Development Query URL in the Subgraph Studio.

Note - Studio API is rate-limited. Hence should preferably be used for development and testing.

To learn more about querying data from your subgraph, see the Querying a Subgraph page.