Monitor Usdc Pairs

Monitor pump.fun USDC-paired coins

When to use

• The user wants a feed of USDC-pair launches, trades, fee claims, or graduations.
• An existing monitor consumes all pump events and the user wants to filter or split USDC out.
• A Telegram channel / dashboard / webhook consumer needs USDC-pair-specific formatting.

Key references

• @pumpkit/core — LaunchMonitor, WhaleMonitor, ClaimMonitor already exist
• packages/channel/ — uses typed V2 decoders (recent refactor)
• tutorials/54-indexing-v2-events.md — ingestion approaches at scale
• tutorials/43-understanding-pumpfun-events.md — event taxonomy

Workflow

1. Pick the ingestion approach

2. Filter for USDC pair

import { PublicKey } from '@solana/web3.js';

const USDC_MAINNET = new PublicKey('EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v');

function isUsdcPair(event: any): boolean {
  // V1 events have no quoteMint — always SOL pair
  if (!event.quoteMint) return false;
  return event.quoteMint.equals(USDC_MAINNET);
}

3. Format with the correct decimals

function formatQuoteAmount(quoteMint: PublicKey, amount: bigint): string {
  if (quoteMint.equals(USDC_MAINNET)) {
    return `${(Number(amount) / 1e6).toFixed(2)} USDC`;
  }
  // SOL / WSOL: 9 decimals
  return `${(Number(amount) / 1e9).toFixed(4)} SOL`;
}

USDC is 6 decimals, SOL/WSOL is 9. Mixing them is a frequent bug.

4. Wire to the existing monitor

import { LaunchMonitor } from '@pumpkit/core';

const monitor = new LaunchMonitor({
  rpcUrl: process.env.SOLANA_RPC_URL!,
  onLaunch: async (event) => {
    if (!isUsdcPair(event)) return;
    await bot.send(USDC_CHAT_ID, formatLaunch(event));
  },
});

await monitor.start();

5. Don't re-decode bytes by hand

Use the typed V2 decoders from @nirholas/pump-sdk (channel/event-monitor refactor commits 1bfec69, 54768bc). Hand-rolled byte parsing will drift when the program ships changes.

6. Deduplicate

USDC events come in over re-subscribes and Geyser slot replays. Dedup on (signature, instruction_index):

const seen = new Set<string>();
function dedupe(sig: string, ix: number) {
  const k = `${sig}:${ix}`;
  if (seen.has(k)) return true;
  seen.add(k);
  return false;
}

Common needs

Avoid

• Sending USDC amounts formatted with 9 decimals. Off by 1000x.
• Reading event.quoteMint on V1 events. It doesn't exist; you'll get undefined.
• Single global subscription for everything. If one handler throws, none of the others get the event. Wrap each handler in try/catch.
• Polling getProgramAccounts for "all USDC curves". Expensive and racy. Subscribe to events, persist them, query your DB.

See also

• .claude/skills/launch-usdc-pair/SKILL.md — launch side
• .claude/skills/index-pump-events/SKILL.md — indexing at scale
• tutorials/54-indexing-v2-events.md
• packages/core/src/monitor/