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Token Airdrops

Gumdrop is a new feature from the metaplex community. It is currently in BETA so use at your own risk.

The Gumdrop program leverages the Solana blockchain and merkle trees to facilitate airdrops to a large number of whitelisted users at a low cost to creators. Users have to redeem the airdrop, it will not automatically appear in their wallet.

Motivation

Various ecosystem projects desire to ensure early followers and supporters gain access to project assets whether they be tokens, NFTs, or others. Simultaneously, capitalization of these assets should not incur undue costs or operational overhead to the creators. There are several ways to achieve such a setup and Gumdrop offers one that integrates with existing Solana and Metaplex ecosystem programs.

Gumdrop solves this efficient-airdrop issue by utilizing a space-efficient hash structure (the merkle tree) such that an on-chain program can validate whether the user is part of a whitelist. This uses a pull-based paradigm to shift the burden from creators, sending airdrops or pre-minting NFTs, to recipients, that can choose to claim their portion or leave it for general adoption.

The approach, originally pioneered for token airdrops by Uniswap and ported to Solana by Saber, is extended to allow printing editions of a master copy. Moreover, Gumdrop allows creators to directly send whitelisted users a drop reclamation link by building the tree with off-chain handles (e.g email, discord, etc.) and allowing the user to redeem into any wallet.

Setup

Gumdrop creators can use either the Gumdrop CLI or the web UI. Additional options are available through the CLI. To execute the Gumdrop CLI or deploy a local version of the web UI, please follow the same prerequisite steps of Candy Machine creation.

  • The CLI can be found in the Gumdrop repo at packages/cli/src/gumdrop-cli.ts and will also be run with ts-node.
  • The web interface can be run locally from the Gumdrop repo at packages/gumdrop with yarn start. (You can also use an example deployment, but this site may not exist for long.)

To create a drop, you must specify the drop type, the distribution method, and the whitelist. When creating the drop, a throwaway Keypair will be generated that holds authority over the on-chain Gumdrop state. This can be used to later close the gumdrop, so make sure to save it!

Drop Types

There are multiple drop types supported by the gumdrop program. Each utilizes the same underlying mechanism of building a merkle tree from a whitelist and using some kind of off-chain distribution method to notify recipients.

The sections below give examples and explanations for CLI usage of the command line flags. A full list of options can be viewed with

$ ts-node src/gumdrop-cli.ts help create

Token Airdrop

All a token airdrop requires is approval to move the relevant tokens from the Gumdrop creators' token account.

$ ts-node src/gumdrop-cli.ts create \
--claim-integration transfer \
--transfer-mint So11111111111111111111111111111111111111112

However, by default, gumdrop-cli.ts will instead transfer the tokens to the generated throwaway Keypair so that multiple gumdrops can be created more intuitively. These will be transferred back on close

Alternatively, by passing --delegate-only, Gumdrop state will be approved as a delegate for the sum of tokens specified.

NFT Candy Machine Pre-sale

The workflow for a Candy Machine pre-sale through the Gumdrop program is as follows:

  1. Create a whitelist mint token WLIST with the SPL token program

  2. Create a Candy Machine V2 with whitelist mint settings with mint WLIST (Candy Machine Docs). For example,

    {
    "whitelistMintSettings": {
    "mode": "burnEveryTime",
    "mint": <WLIST>,
    "presale": true,
    "discountPrice": null
    },
    ...
    }
  3. Create a Gumdrop with --claim-integration candy and the corresponding --candy-machine.

    $ ts-node src/gumdrop-cli.ts create \
    --claim-integration candy \
    --candy-machine FuxMhU34GPggi1yzk8tQwhsLQFR52iiutM5B9nzzeRPa \

    gumdrop-cli.ts will parse the on-chain candy machine account and look for the corresponding whitelistMintSettings. Then under-the-hood it initializes a token-airdrop for WLIST but adds extra information in the claim URL so that frontends can find the corresponding candy crank in addition to the whitelist token account. In the produced urls.json, this will look something like

    ...
    ?distributor=9zXd1NddYbZejacgd92XMQsAQKhXC4Yj9rhUspRyR1ud\
    &candy=FuxMhU34GPggi1yzk8tQwhsLQFR52iiutM5B9nzzeRPa\
    &tokenAcc=93fQV4RnstogfFqMstV9b8uAvZ5KsRFjgJUagJhpX2Wa\
    ...
  4. On the frontend, users click a button that formats 2 transactions. The first claims the whitelist token gumdrop, and the second uses that token to crank the candy machine.

Edition Prints

Similarly, the Gumdrop will act as a proxy for the owner of the master edition and allow minting of limited editions. Ownership of the master edition will be transferred to the Gumdrop state for the duration of the Gumdrop!

$ ts-node src/gumdrop-cli.ts create \
--claim-integration edition \
--edition-mint 7Hy3FqSQYiXyg4fyobZnSJhMvAqMmraBLaTq9QSFF9ip

Closing the Gumdrop will reclaim the master edition.

Distribution Method

The distribution method is used to notify recipients that they have received a Gumdrop. Currently, the Gumdrop frontends support email, SMS, and discord notifications.

For email and SMS,

$ ts-node src/gumdrop-cli.ts create \
--distribution-method aws-email|aws-sms \
--aws-access-key-id "$AWS_ACCESS_KEY_ID" \
--aws-secret-access-key "$AWS_SECRET_ACCESS_KEY"

For Discord,

$ ts-node src/gumdrop-cli.ts create \
--distribution-method discord \
--discord-token "$DISCORD_TOKEN"

With each of these methods, creators can also choose to enable OTP verification with the --otp-auth flag. Enable and disable with --otp-auth enable and --otp-auth disable respectively. In case OTP verification is configured, the same distribution method will be used to verify the OTP.

Alternatively, creators can also choose to build the Gumdrop from public keys which allows only the owner of said public key to claim the Gumdrop. In this case, the full list of URLs is expected to be uploaded by the creator somewhere.

$ ts-node src/gumdrop-cli.ts create \
--distribution-method wallets

Whitelist

The whitelist is used to specify the recipients of the Gumdrop. Both frontends expect the whitelist to be a JSON list of recipients, each with a handle identifying the user, an amount which determines the number of tokens, mints, or prints that can be claimed, and in the case of edition prints, an edition number.

More concretely, the frontends expect the list format to be

[
{
"handle": "<DISTRIBUTION-METHOD-SPECIFIC-HANDLE>",
"amount": <GUMDROP-CLAIM-ALLOWANCE>,
["edition": <EDITION-NUMBER>]
},
...
]

The distribution method handles are as follows:

TypeFormatExample
Emaillocal-part@domainjohn.smith@example.com
SMSE.164+18005550100
DiscordUser ID898959704573759608
Walletswallet public key8mTVkib7TwUSsZRTHDQy9EQbw7ZR7xLrvKeyPgkFPgZB

At the moment, Discord handles are the hardest to programmatically create. One option is to query for members in a Discord Guild and filter for the relevant users by display-name there.

The distribution list has to be referenced in the create command like this:

$ ts-node src/gumdrop-cli.ts create \
--distribution-list <PATH TO WHITELIST JSON>

NB: The frontends do some verification that the Gumdrop being created is sufficient to satisfy all the recipients specified. However, these checks are all dependent on the good behavior of the creator! For example, if the creator, after creating a token-Gumdrop, moves all the tokens out of their wallet, recipients will fail to claim their allocation.

Closing a Gumdrop

When the gumdrop is finished, the master edition can be reclaimed by closing the gumdrop. Currently, the small portion of rent used to store the Gumdrop state is also redeemed but please do not rely on this behavior!

The command to close it is:

ts-node gumdrop-cli.ts close \
--base <id.json keypair that was created on gumdrop create> \
--keypair <your initial keypair> \
--claim-integration <creation --claim-integration> \
--<corresponding claim integration flag>

We pass additional information about the claim integration to revoke authority or transfer back tokens, etc.

NB: somewhat obviously, recipients will no longer be able to redeem the Gumdrop after it is closed.

Deploy Custom Gumdrop Site

This method applies to only Vercel. In the gumdrop directory, remove homepage key-value entirely. Connect your GitHub to Vercel and create a new project. In the project setup, make sure these settings are set.

Build and Development Settings

Root Directory Settings