🗺️ Claim Map

This page documents the Claim Map PDA Account.

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📘 Overview

A Claim Map is a bitmap-based structure used to track which addresses have already claimed tokens from a specific airdrop.

It allows Dropsy to:

• Efficiently store claim status
• Avoid double-claims
• Support extremely large airdrop lists (100k+ entries)
• Use a compact bitmap instead of storing a list

Each ClaimMap belongs to a specific Airdrop, and each map represents a segment of the claiming list.

This design allows scalable, gas-efficient claiming with minimal storage use.

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🔐 PDA Derivation

ClaimMap PDAs are derived using:

Where:

• claim_map → static namespace seed
• airdrop → the parent Airdrop PDA
• id → the bitmap segment index (0, 1, 2, …)

Each bitmap typically covers 8,192 claim slots (or the size defined in program constants).

Derive Claim Map Pda Example

import {
  Address,
  getAddressEncoder,
  getProgramDerivedAddress,
  ProgramDerivedAddressBump,
  ReadonlyUint8Array,
} from "@solana/kit";

export type DropsyPda = readonly [Address<string>, ProgramDerivedAddressBump];
type Seed = ReadonlyUint8Array | string;

export async function getClaimMapDerivedAddress(
  airdrop: Address,
  id: number
): Promise<DropsyPda> {
  const seeds = [
    Buffer.from("bitmap"),
    getAddressEncoder().encode(airdrop),
    Buffer.from([id]),
  ];
  return await getProgramDerivedAddress({
    seeds,
    programAddress: DROPSY_PROGRAM_ADDRESS,
  });
}

🧱 Account Structure

Field	Type	Description
discriminator	ReadonlyUint8Array	Anchor 8-byte account discriminator.
authority	Address	Authority allowed to update or close the ClaimMap.
airdrop	Address	The parent Airdrop this map belongs to.
claimedBitmap	ReadonlyUint8Array	Bitmap where each bit represents whether an index has claimed.
total	number	Number of total claimable addresses stored in this ClaimMap segment.
id	number	Sequential identifier of this bitmap (0,1,2…).
version	number	ClaimMap version.
bump	number	PDA bump.

📥 Fetch Claim-Map Account

import { address } from "@solana/kit";
import { fetchClaimMap } from "@dropsy/sdk";

// The AirdropMaster PDA you want to fetch
const claim_map_address = address("12354.....abndks");

(async () => {
  try {
    const claim_map = await fetchClaimMap(rpc, claim_map_address);

    console.log("claim_map Loaded:");
    console.log("Authority:", claim_map.authority.toString());
  } catch (err) {
    console.error("Failed to fetch ClaimMap:", err);
  }
})();