Create a new Ponder project

Run the create-ponder CLI tool

This command creates a project folder called ponder in the current working directory. There are two templates for getting started:

a) Etherscan contract link

The --from-etherscan option bootstraps a Ponder project for a deployed contract. Replace the ... with a link to a contract page on Etherscan (also accepts Polygonscan, Arbiscan, etc).

pnpm create ponder --from-etherscan <link>

b) Blank slate

If you don't have a contract in mind, this command will create a Ponder project for a sample NFT contract. Soon, create-ponder will support more template options, like Foundry and Hardhat projects.

pnpm create ponder

Start the development server

The dev server is central to the Ponder development workflow. Just like Next.js, the dev server automatically reloads when you save changes in any project file. It also prints console.log statements and errors encountered while running your code.

cd ponder
pnpm dev

Add an RPC URL

Ponder fetches data using the Ethereum RPC API. To get started, you'll need an RPC URL from a provider like Alchemy or Infura.

Open up .env.local and paste in RPC URLs for any networks that your project uses:

PONDER_RPC_URL_1 = "https://eth-mainnet.g.alchemy.com/v2/..."

Define your schema

The schema.graphql file defines the entity objects that our GraphQL API will serve. Any types marked with the @entity directive will become available as entity models in your handler functions.

Using this schema, Ponder automatically generates a GraphQL API that serves entity data.

Write event handlers

The files in the src/ directory contain event handlers. Event handlers are JavaScript functions that accept a contract event and insert data into the entity store.

Here's a sample event handler for an ERC721 Transfer event.

import { ponder } from "../generated";
 
ponder.on("MyNftContract:Transfer", async ({ event, context }) => {
  const { Token } = context.entities;
  const { MyNftContract } = context.contracts;
 
  // Get an entity object
  const token = await Token.get(event.params.id);
 
  // Call a contract read function
  const tokenUri = await MyNftContract.tokenUri(token.id);
 
  // ...
});

Query the GraphQL API

As you write your event handlers and start inserting entity data, open the GraphiQL interface at http://localhost:42069/graphql to explore your GraphQL API locally. Any changes you make to your schema.graphql file will be reflected here.