Agent-Based Airdrops Across Chains

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Designing a Scalable and Secure Airdrop System with Fetch.ai Agent Technology

Airdrops have become a popular strategy in Web3 — used to reward users, promote community engagement, and bootstrap token ecosystems. However, distributing tokens across multiple blockchain networks (like Ethereum, Solana, and Fetch.ai) introduces challenges:

How do you verify user identity across wallets on different chains?
How do you query token holdings securely and accurately?
How do you prevent replay or duplicate claims?
And how do you automate the token release process without relying on centralized control?

In this post, we’ll show you how to design a cross-chain, agent-based airdrop system using Fetch.ai’s agent framework. This approach enables:

✅ Verifiable user identity across chains
✅ Automated balance verification
✅ Logic-based reward calculation
✅ Fully on-chain token distribution — without human intervention

Let’s walk through the entire system from start to finish.

System Overview

We’ll build a decentralized airdrop flow with the following steps:

A user registers through a DApp and signs a challenge using their wallets on Ethereum, Solana, and Fetch.
These signed messages are collected and sent to an autonomous Airdrop Agent.
The agent:
- Verifies wallet ownership
- Queries balance or staking data
- Calculates the reward
- Generates and signs a release attestation
This attestation is submitted to a smart contract, which verifies it and sends Token A to the user’s wallet.

Here’s how the full flow looks visually:

Airdrop Contract:

The smart contract is designed to:

Hold airdrop funds (e.g., Token A)
Release tokens only when it receives a valid, signed release attestation from the Airdrop Agent
Prevent multiple claims from the same address

This ensures:

✅ Verifiable, rule-based fund release
✅ No centralized admin intervention
✅ On-chain traceability of claims

Airdrop Agent — Registration Attestation

To prove wallet ownership across chains, the user must sign a challenge message with each wallet. These signatures form attestations and are sent to the agent.

Here’s the data structure used for registering a user:

class AttestationContent(BaseModel):
    validFrom: str
    validTo: str
    fetchNativeAddress: str
    ethAddress: str
    solanaAddress: str

class Attestation(BaseModel):
    network: Literal['fetch', 'eth', 'solana']
    signature: str  # base64 encoded signature

class AirdropRegistration(BaseModel):
    attestation: AttestationContent
    attestations: list[Attestation]

This data structure includes:

The time range in which the attestation is valid
The wallet addresses on all supported chains
The signature for each network’s challenge

The Airdrop Agent uses this data to verify that all addresses belong to the same user.

Encoding the Attestation for Signing

Before signing, the attestation content is encoded using a consistent and deterministic format to ensure cross-platform compatibility.

import struct

def encode_string(value: str) -> bytes:
    """Encodes a string with an 8-byte length prefix."""
    return struct.pack('>Q', len(value)) + value.encode('utf8')

def encode_attestation(atte: AttestationContent) -> bytes:
    fields = [
        atte.validFrom,
        atte.validTo,
        atte.fetchNativeAddress,
        atte.ethAddress,
        atte.solanaAddress,
    ]

    encoded = b""
    for field in fields:
        encoded += encode_string(field)

    return encoded

The signature can then be generated by signing the output of the encode_attestation function. The signature should be base64 encoded into the final Attestation structure.

Airdrop Agent — Release Attestation

Once wallet ownership is verified and token holdings are confirmed, the Airdrop Agent computes the airdrop amount and generates a release attestation:

class ReleaseAttestation(BaseModel):
    destination: str   # The user's wallet address
    amount: str        # Amount of Token A
    signature: str     # Signed by Airdrop Agent's private key

The above is the attestation that should be generated from the airdrop agent. Specifically the destination and amount fields will need to be encoded and signed. In addition, we need to verify that on the SVM the attestation can be verified correctly to release the funds.

On-Chain Execution

Once the release attestation is received, the smart contract performs the following steps:

Validates the agent’s signature using a predefined public key
Checks for double claims by tracking previously claimed addresses or hashes
Transfers Token A to the user’s wallet

This makes the entire token distribution autonomous, secure, and fully auditable on-chain.

Final Thoughts

Agent-based airdrops are a significant upgrade over manual distribution tools. This system design is:

Scalable — works across thousands of users and multiple blockchains
Secure — uses cryptographic signatures and on-chain enforcement
Reusable — the agent’s logic can be easily modified for future campaigns
Transparent — every claim is verifiable through on-chain proofs

With Fetch.ai’s agent framework, you can automate identity checks, verify balances, and issue airdrops programmatically — all without maintaining off-chain servers or relying on centralized validators.

Whether you’re launching a new token, rewarding stakers, or running a governance campaign — agent-based infrastructure gives you complete control, flexibility, and security.

Learn More

Ready to explore what’s possible with agent-based automation?

The uAgents Framework by Fetch.ai makes it simple to build intelligent, event-driven, and secure agents in Python. Whether you’re automating cross-chain airdrops, building decentralized coordination tools, or exploring agent-based trading, uAgents gives you the power to move fast and build autonomously.

What is uAgents?

uAgents is an open-source Python library designed for creating autonomous AI agents. With intuitive decorators and event-driven patterns, you can build agents that:

🕒 Perform scheduled tasks
🧠 React to on-chain or external events
🔐 Communicate securely across networks
🌐 Coordinate between blockchains, APIs, and other agents

It’s lightweight, flexible, and built for real-world applications in Web3 and beyond.Key Resources

Key Resources

GitHub Repository: github.com/fetchai/uAgents
Official Docs: https://fetch.ai/docs
X: @Fetch_ai
Community Discord: https://discord.gg/fetchai

💡 Need Help Getting Started?

We’d love to support your journey.

Whether you’re just exploring or already building, our team and community can help you with:

✅ Templates and starter kits for agent-based solutions
✅ Best practices for testing, deploying, and scaling agents
✅ Hands-on guidance with wallet integrations, message flows, and smart contract coordination

Have a project or idea in mind?

👉 Join the Fetch.ai Discord to connect with the team, ask questions, and start building. We’re excited to see what you create.

#BUIDLFETCH 🚀

Agent-Based Airdrops Across Chains was originally published in Fetch.ai on Medium, where people are continuing the conversation by highlighting and responding to this story.

1M ago•

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