Get started
What is Ponder?
Ponder is an open-source framework for custom Ethereum indexing.
You write TypeScript code to transform onchain data into your application's schema. Then, Ponder fetches data from the chain, runs your indexing logic, and writes the result to Postgres.
Once indexed, you can query the data through GraphQL, SQL over HTTP, or directly in Postgres.
Quickstart
Run create-ponder
The quickest way to create a new Ponder project is create-ponder
, which sets up everything automatically for you.
pnpm create ponder
On installation, you'll see a few prompts.
✔ What's the name of your project? › new-project
✔ Which template would you like to use? › Default
✔ Installed packages with pnpm.
✔ Initialized git repository.
This guide follows the ERC-20 example, which indexes a token contract on Ethereum mainnet.
Start the dev server
After installation, start the local development server.
pnpm dev
Ponder will connect to the database, start the HTTP server, and begin indexing.
12:16:42.845 INFO Connected to database type=postgres database=localhost:5432/demo (35ms)
12:16:42.934 INFO Connected to JSON-RPC chain=mainnet hostnames=["eth-mainnet.g.alchemy.com"] (85ms)
12:16:43.199 INFO Created database tables count=4 tables=["account","transfer_event","allowance","approval_event"] (17ms)
12:16:43.324 INFO Created HTTP server port=42069 (5ms)
12:16:43.325 INFO Started returning 200 responses endpoint=/health
12:16:43.553 INFO Started backfill indexing chain=mainnet block_range=[13142655,13150000]
12:16:43.555 INFO Started fetching backfill JSON-RPC data chain=mainnet cached_block=13145448 cache_rate=38.0%
12:16:43.796 INFO Indexed block range chain=mainnet event_count=4259 block_range=[13142655,13145448] (164ms)
12:16:43.840 INFO Indexed block range chain=mainnet event_count=33 block_range=[13145449,13145474] (4ms)
Query the database
Visit localhost:42069/graphql in your browser to explore the auto-generated GraphQL API. Here's a query for the top accounts by balance, along with the total number of accounts.
query {
accounts(orderBy: "balance", orderDirection: "desc", limit: 2) {
items {
address
balance
}
totalCount
}
}
Customize the schema
Let's add a new column to a table in ponder.schema.ts
. We want to track which accounts are an owner of the token contract.
import { index, onchainTable, primaryKey, relations } from "ponder";
export const account = onchainTable("account", (t) => ({
address: t.hex().primaryKey(),
balance: t.bigint().notNull(),
isOwner: t.boolean().notNull(),
}));
// ...
Immediately, there's a type error in src/index.ts
and a runtime error in the terminal. We added a required column, but our indexing logic doesn't include it.
12:16:16 PM ERROR indexing Error while processing 'ERC20:Transfer' event
NotNullConstraintError: Column 'account.isOwner' violates not-null constraint.
at /workspace/new-project/src/index.ts:10:3
8 |
9 | ponder.on("ERC20:Transfer", async ({ event, context }) => {
> 10 | await context.db
| ^
11 | .insert(account)
12 | .values({ address: event.args.from, balance: 0n })
13 | .onConflictDoUpdate((row) => ({
Update indexing logic
Update the indexing logic to include isOwner
when inserting new rows into the account
table.
import { ponder } from "ponder:registry";
import { account } from "ponder:schema";
const OWNER_ADDRESS = "0x3bf93770f2d4a794c3d9ebefbaebae2a8f09a5e5";
ponder.on("ERC20:Transfer", async ({ event, context }) => {
await context.db
.insert(account)
.values({
address: event.args.from,
balance: 0n,
isOwner: event.args.from === OWNER_ADDRESS,
})
.onConflictDoUpdate((row) => ({
// ...
})
As soon as we save the file, the dev server hot reloads and finishes indexing successfully.
12:19:31.629 INFO Hot reload "src/index.ts"
12:19:31.889 WARN Dropped existing database tables count=4 tables=["account","transfer_event","allowance","approval_event"] (3ms)
12:19:31.901 INFO Created database tables count=4 tables=["account","transfer_event","allowance","approval_event"] (12ms)
12:19:32.168 INFO Started backfill indexing chain=mainnet block_range=[13142655,13150000]
12:19:32.169 INFO Started fetching backfill JSON-RPC data chain=mainnet cached_block=13147325 cache_rate=63.6%
12:19:32.447 INFO Indexed block range chain=mainnet event_count=6004 block_range=[13142655,13146396] (199ms)
12:19:32.551 INFO Indexed block range chain=mainnet event_count=3607 block_range=[13146397,13147325] (104ms)
Next steps
This quickstart only scratches the surface of what Ponder can do. Take a look at the examples directory for more complex projects, or the GitHub dependents for a list of real-world repositories using Ponder.
Or, continue reading the guides and API reference here on the documentation site.