Quickstart

Create a new Ponder project

pnpm create ponder

You will be asked for a project name, and if you are using a template (recommended). Then, it will create a project directory, install dependencies, and initialize a git repository.

Start the development server

Just like Next.js and Vite, Ponder has a development server that automatically reloads when you save changes in any project file. It also prints console.log statements and errors encountered while running your code.

First, cd into your project directory, then start the server.

pnpm dev

Add an RPC URL

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

Open .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/..."

Design your schema

The schema.graphql file contains a model of your application data. The entity types defined here can be thought of as database tables.

type BlitmapToken @entity {
  id: String!
  owner: String! # Ethereum address
}

See Design your schema for a detailed guide on schema design.

Write event handler functions

Files in the src/ directory contain event handler functions, which are simply TypeScript functions that process a contract event. The purpose of event handler functions is to insert data into the entity store.

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

import { ponder } from "@/generated";
 
ponder.on("Blitmap:Transfer", async ({ event, context }) => {
  const { BlitmapToken } = context.entities;
 
  await BlitmapToken.create({
    id: event.params.tokenId,
    data: {
      owner: event.params.to,
    },
  });
});

See Create & update entities for a detailed guide on writing event handlers.

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.

query {
  blitmapTokens {
    id
    owner
  }
}

{
  "blitmapTokens": [
    { "id": 1452, "owner": "0xaf3d5..." },
    { "id": 7164, "owner": "0x9cb3b..." },
  ]
}