The blockchain ecosystem often sees projects issuing their initial tokens as ERC20 assets on the Ethereum network before launching their own mainnet. This approach is common for fundraising and community building. Once the mainnet is live, these tokens must be migrated or mapped from the Ethereum blockchain to the new native network. This process ensures that holders of the ERC20 tokens receive an equivalent amount of the native mainnet asset.
This transition is not merely a technical formality. It is a critical process that guarantees the continuity of value and ownership for investors and users. A secure, efficient, and well-communicated migration is vital for maintaining trust in the project. Failures in this process can lead to lost funds, frustrated communities, and significant reputational damage.
This guide explores the core requirements for a successful mainnet swap and details three primary methods projects use to facilitate this crucial transition.
Core Requirements for a Mainnet Token Swap
Migrating from an ERC20 token to a native mainnet coin involves several key technical and logistical steps. The overarching goal is to transfer value from one blockchain to another without compromising security or ownership. The following tasks are essential for any successful migration.
1. Address Mapping Collection
The project must create a secure and reliable method to collect the correlation between a user's Ethereum address (holding the ERC20 tokens) and their new mainnet address. This process must be designed to prevent fraudulent claims and ensure that only the legitimate token holder can specify the destination address.
2. ERC20 Token Balance Snapshot
A definitive record of every Ethereum address's token balance must be taken at a specific block height. This snapshot serves as the immutable source of truth for determining how many new native tokens each user should receive.
3. Native Token Distribution
Based on the collected address map and balance snapshot, the project's team must execute the distribution of the new native tokens on the mainnet to the corresponding addresses.
4. ERC20 Token Retirement
To prevent double-spending or confusion, the original ERC20 tokens must be effectively removed from circulation, or "burned," after the successful distribution of the mainnet tokens.
The Role of a Mapping Smart Contract
A dedicated smart contract on the Ethereum network is the most secure and decentralized method for handling the address mapping process. This contract allows users to autonomously register their mainnet address by signing a transaction with the private key of their Ethereum wallet. This cryptographic proof ensures that only the legitimate owner of the ERC20 tokens can initiate the mapping request.
The contract typically contains a function, often called register, which accepts a string parameter (the new mainnet public address). When a user calls this function, the contract stores the pairing of their Ethereum address (msg.sender) and the provided mainnet address.
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Key advantages of using a mapping contract:
- User Sovereignty: Users maintain control over their private keys throughout the process.
- Transparency: The mapping data is recorded on the public Ethereum blockchain for anyone to verify.
- Security: The requirement of a signed transaction prevents unauthorized address registration.
For a migration to be successful, it's not enough to just deploy a smart contract. Projects must provide a user-friendly solution that guides holders through the entire process. This includes helping users generate a new mainnet keypair, safely interact with the mapping contract, and verify that their registration was successful.
Three Primary Methods for Token Migration
Different projects have adopted various strategies to facilitate the token swap, each with its own trade-offs between user control, ease of use, and technical complexity. Here are three prominent real-world examples.
Manual Process for Technical Users (EOS)
The EOS migration was a largely manual process designed for users comfortable with managing their own keys and interacting with smart contracts directly. The project provided detailed guides and a mapping website for generating EOS keypairs. However, the actual act of calling the mapping contract had to be performed by the user using their preferred Ethereum wallet (like MetaMask or MyEtherWallet).
- Pros: Maximizes decentralization and user control; no need to trust a third party.
- Cons: High risk of user error; requires significant technical knowledge; a poor experience for non-technical holders.
Centralized Exchange-Mediated Swap (TRON - TRX)
TRON (TRX) opted for a highly user-friendly approach by leveraging centralized cryptocurrency exchanges. The project announced that users could deposit their ERC20 TRX tokens into participating exchange platforms. The exchanges then handled the entire technical process of mapping addresses and swapping tokens on behalf of their users. Once the swap was complete, users found their new native TRX tokens in their exchange accounts.
- Pros: Extremely simple for users; eliminates the potential for individual user error.
- Cons: Users must trust the exchange with their funds; requires users to have an account on a specific exchange; goes against the decentralized ethos for some.
Dedicated Wallet Integration (Qtum)
Qtum implemented a solution that balanced ease of use with user control. They facilitated the token swap through a dedicated wallet application that supported both Ethereum (for holding the ERC20 tokens) and the Qtum mainnet. The wallet provided a built-in interface that guided users through the steps of the swap, including the crucial address mapping step, all within a single application.
- Pros: More user-friendly than a fully manual process; reduces the chance of error; users typically retain custody of their keys.
- Cons: Users must download and trust a specific wallet application; development resource-intensive for the project.
How Are ERC20 Tokens Destroyed?
Completing the token lifecycle requires rendering the old ERC20 tokens obsolete. The method of "burning" these tokens varies depending on the original smart contract's design.
Built-in Contract Functionality
Some forward-thinking projects, like EOS, build a self-destruct mechanism directly into their ERC20 token contract. This is often a function like stop() or pause() that can be activated by the contract owner after a certain date. Once called, all token transfers are frozen permanently, effectively removing the tokens from circulation and completing the burn process programmatically.
Transfer to a Burn Address
For tokens that lack a built-in burn function, the standard practice is to instruct users to send their ERC20 tokens to a specific Ethereum address from which the private keys are unknown or purposefully destroyed. This could be the address of the mapping contract itself or a designated "dead" address (e.g., 0x000...000). Once sent to this address, the tokens are permanently lost and considered burned.
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Frequently Asked Questions
What is the main purpose of a token migration?
A token migration transfers the value of a project's asset from a temporary standard, like an ERC20 token on Ethereum, to its own independent blockchain (mainnet). This allows the project to leverage its own network's features, security, and governance model.
Do I have to participate in a token swap?
Yes, if you hold ERC20 tokens for a project that has migrated to its mainnet. If you do not participate within the specified timeframe, your ERC20 tokens will likely become worthless, and you will not receive the native mainnet tokens.
Which migration method is the safest?
The "safest" method depends on your priorities. A manual swap using a mapping contract is safest from a trust perspective, as you never give up custody of your keys. Using a major, reputable exchange is safest from an ease-of-use perspective, as it minimizes technical risk for you.
What happens if I send my tokens to the wrong address during a swap?
This is a critical error. Tokens sent to an incorrect address are typically lost forever with no possibility of recovery. It is crucial to double-check all addresses and carefully follow the project's official instructions.
How long do token swaps usually take?
Projects always announce a specific swap period, which can range from several weeks to many months. It is imperative to complete the process within this window. Most projects will not support swaps after the deadline has passed.
Can I swap my tokens after the migration period ends?
Typically, no. The ability to swap tokens is almost always limited to a announced period. After this, the old token contract is often frozen or the supporting infrastructure is shut down, making swaps impossible. Always act before the deadline.