Ponder Skill

What is Ponder

Ponder is an open-source TypeScript framework that indexes EVM blockchain data into Postgres with type-safe APIs. It replaces subgraphs with 10-15x faster indexing, hot reloading, and zero-codegen type safety.

Architecture flow: ponder.config.ts (what to index) -> ponder.schema.ts (where to store) -> src/*.ts (how to transform) -> src/api/index.ts (how to query)

Stack: v0.16.x, Drizzle ORM, Hono for HTTP, viem for Ethereum.

Quick Start

Scaffold

pnpm create ponder  # also: npm, yarn, bun

Requirements

• Node >= 18.18, TypeScript >= 5.0.4, viem >= 2, hono >= 4.5

tsconfig.json (exact)

{
  "compilerOptions": {
    "strict": true,
    "noUncheckedIndexedAccess": true,
    "target": "ES2022",
    "module": "ES2022",
    "moduleResolution": "bundler",
    "esModuleInterop": true,
    "skipLibCheck": true
  }
}

ponder-env.d.ts

Must exist at project root. Run ponder codegen to generate it.

Environment Variables

• PONDER_RPC_URL_<CHAIN_ID> - RPC endpoint per chain (e.g., PONDER_RPC_URL_1 for mainnet)
• DATABASE_URL - Postgres connection string (production)
• DATABASE_SCHEMA - Schema isolation name (production)

Minimal Working Example

ponder.config.ts:

import { createConfig } from "ponder";
import { http } from "viem";
import { ERC20Abi } from "./abis/ERC20Abi";

export default createConfig({
  chains: {
    mainnet: { id: 1, rpc: process.env.PONDER_RPC_URL_1 },
  },
  contracts: {
    USDC: {
      abi: ERC20Abi,
      chain: "mainnet",
      address: "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
      startBlock: 6082465,
    },
  },
});

ponder.schema.ts:

import { onchainTable } from "ponder";

export const transfers = onchainTable("transfers", (t) => ({
  id: t.text().primaryKey(),
  from: t.hex().notNull(),
  to: t.hex().notNull(),
  amount: t.bigint().notNull(),
  timestamp: t.integer().notNull(),
}));

src/index.ts:

import { ponder } from "ponder:registry";
import { transfers } from "ponder:schema";

ponder.on("USDC:Transfer", async ({ event, context }) => {
  await context.db.insert(transfers).values({
    id: event.id,
    from: event.args.from,
    to: event.args.to,
    amount: event.args.value,
    timestamp: Number(event.block.timestamp),
  });
});

src/api/index.ts:

import { Hono } from "hono";
import { db } from "ponder:api";
import { graphql } from "ponder";
import * as schema from "ponder:schema";

const app = new Hono();
app.use("/graphql", graphql({ db, schema }));
export default app;

CLI Commands

Exit codes: 75 = retryable (safe to auto-restart), 1 = fatal (check logs).

Decision Heuristics

Ordering Mode

Table vs View

• Table (onchainTable): Data written by indexing functions. Source of truth.
• View (onchainView): Aggregations/rollups computed at query time. No writes, no store API.

Store API vs Raw SQL

• Store API (context.db): Always prefer in indexing functions. 100-1000x faster (batched writes).
• Raw SQL (db.sql): Only for complex multi-table updates that Store API cannot express.

Factory vs Explicit Addresses

• factory(): Contract instances created dynamically at runtime (Uniswap pools, token clones).
• Explicit address: Known addresses at config time. Use array for multiple fixed addresses.

Call Traces vs Events

• Events: Default choice for most indexing use cases.
• Call traces (includeCallTraces: true): Only when you need function inputs/outputs not emitted as events. Requires debug_traceBlockByNumber RPC support.

includeTransactionReceipts

Only enable when you need gasUsed, logs from other contracts, or tx status. Adds significant RPC overhead.

PGlite vs Postgres

• PGlite: Dev only (ponder dev uses it automatically).
• Postgres: Any shared or production environment.

GraphQL vs Custom Routes

• GraphQL middleware: Standard CRUD with built-in filtering, sorting, pagination.
• Custom Hono routes: Complex joins, aggregations, non-standard responses, or non-GraphQL APIs.

Gotchas and Anti-Patterns

Setup

• ABIs MUST use as const assertion for type inference:

  export const MyAbi = [...] as const; // REQUIRED

• ponder-env.d.ts must exist and be current. Run ponder codegen after config changes.
• Set startBlock to the contract deployment block, NOT 0. Setting 0 scans entire chain history (hours vs seconds).
• Local dev nodes (Anvil/Hardhat): set disableCache: true in chain config.
• Table/schema names: snake_case, max 45 characters.

Schema

• ANTI-PATTERN: String concatenation for composite keys (${owner}-${spender}). USE: primaryKey({ columns: [table.owner, table.spender] }).
• All addresses are lowercase since v0.12. Never use checksummed addresses.
• Use t.hex() for addresses and byte data, t.bigint() for uint256/int256.
• Always add indexes on columns used in GraphQL filters or API WHERE clauses.

Indexing

• Virtual module imports: ponder:registry, ponder:schema, ponder:api. NOT regular file paths.
• context.db (indexing functions, read-write) vs db from ponder:api (API routes, read-only).
• ANTI-PATTERN: Writing to database in API routes. db from ponder:api is read-only.
• onConflictDoUpdate callback receives the EXISTING row, not the values you passed to .values().
• context.client.readContract automatically scopes reads to the current event's block number.
• Factory contracts: use event.log.address to get which child contract emitted the event.
• Multi-chain shared handlers: use context.chain.id to distinguish chains.
• Execution order per chain: block number -> tx index -> log index (deterministic).
• event.id is a 75-digit string, globally unique across chains.

Deployment

• ponder start requires --schema flag (or DATABASE_SCHEMA env var).
• experimental_isolated ordering requires chainId in ALL table primary keys.

Reference Navigation

Load the appropriate reference based on the task:

Common Task Checklists

Scaffold a New Project

1. Run pnpm create ponder and select template
2. Add RPC URL to .env.local as PONDER_RPC_URL_<CHAIN_ID>
3. Update ponder.config.ts with contract address, ABI, and startBlock
4. Define schema in ponder.schema.ts
5. Write indexing functions in src/index.ts, then run ponder dev

Add a New Contract to Index

1. Add ABI file with as const assertion
2. Add contract entry to ponder.config.ts (abi, chain, address, startBlock)
3. Add tables to ponder.schema.ts for the data you want to store
4. Write handler in src/ using ponder.on("ContractName:EventName", ...)

Add a Factory Contract

1. Import parseAbiItem from viem to define the creation event
2. Use factory() in config: address: factory({ address, event, parameter })
3. Write handler using event.log.address to identify the child contract
4. Schema tables may need composite PKs including the child contract address

Add a Custom API Endpoint

1. Open src/api/index.ts
2. Import db from ponder:api and schema from ponder:schema
3. Add Hono route (app.get("/path", ...)) with Drizzle queries on db.sql

Set Up Multi-Chain Indexing

1. Choose ordering mode (see Decision Heuristics above)
2. Add chain configs for each chain in ponder.config.ts
3. Use composite PKs with chainId if using experimental_isolated
4. Use context.chain.id in handlers when chain-specific logic is needed

Deploy to Production

1. Provision Postgres v14-17 with <50ms latency to app server
2. Set DATABASE_URL and choose a DATABASE_SCHEMA name
3. Run ponder start --schema <name>
4. Health checks: /health (always 200), /ready (503 during backfill, 200 when caught up)
5. For zero-downtime redeploys, use --views-schema pattern