Server Wallets

Deploy and use a wallet from your server in under 5 minutes

In this quickstart you will learn how to create and manage wallets using a REST API from a server environment.

Integration Steps

1

Create a Developer Account and Project

To get started, create a developer account in the Crossmint Staging Console. Open that link, sign in, and accept the dialog to continue.

Crossmint offers two consoles: staging, for development and testing, and www, for production.

Then, navigate to project Settings > General:

• For EVM chains: Set the wallet type to “Smart Wallets”
• For all other chains: Set the wallet type to “Custodial Wallets”

2

Get an API Key

Create a server-side API key with these scopes:

Navigate to the "Integrate" section on the left navigation bar, and ensure you're on the "API Keys" tab.

Within the Server-side keys section, click the "Create new key" button in the top right.

Next, check the scopes labeled wallets.create, wallets.read, wallets.fund, wallets:balance.read, wallets:transactions.create, wallets:transactions.read, wallets:transactions.sign.

Finally, create your key and save it for subsequent steps.

This allows your API key to perform any kind of wallet action.

3

Choose a Wallet Type

Below is a summary of available wallet types and their characteristics:

Chain	Custodial	Type	Admin Signer
EVM	True	evm-smart-wallet	evm-fireblocks-custodial
EVM	False	evm-smart-wallet	evm-keypair
EVM	True	evm-mpc-wallet	None
Solana	True	solana-smart-wallet	solana-fireblocks-custodial
Solana	False	solana-smart-wallet	solana-keypair
Solana	True	solana-mpc-wallet	None
Aptos	True	aptos-mpc-wallet	None
Aptos	False	Contact Support	Contact Support
Cardano	True	cardano-mpc-wallet	None
Cardano	False	Contact Support	Contact Support
Sui	True	sui-mpc-wallet	None
Sui	False	Contact Support	Contact Support

4

Create Your First Wallet

Create a file (e.g. createWallet.ts) and enter this code:

createWallet.ts

const apiKey = "YOUR_API_KEY";
const walletType = "evm-smart-wallet"; // Enter the Type from the table above
const adminSigner = {
    // Enter admin signer from table above, or leave undefined
    type: "evm-fireblocks-custodial",
};

async function createWallet() {
    const response = await fetch("https://staging.crossmint.com/api/2022-06-09/wallets", {
        method: "POST",
        headers: {
            "X-API-KEY": apiKey,
            "Content-Type": "application/json",
        },
        body: JSON.stringify({
            type: walletType,
            config: {
                adminSigner,
            },
        }),
    });

    return await response.json();
}

createWallet()
    .then((json) => console.log(json))
    .catch((err) => console.error(`error: ${err}`));

Before running it, be sure to fill in:

• YOUR_API_KEY with the key obtained in step 2
• Choose your desired wallet type and admin signer from the table above

Now, run the script:

TypeScript

npx tsx createWallet.ts

The API will return a response with your new wallet details. Save the wallet address, as you’ll use it in the next step.

Sample response

{
   "type": "evm-smart-wallet",
   "config": {
       "adminSigner": {
           "type": "evm-fireblocks-custodial",
           "address": "0x92bbE9813D88F36Cb7Fd2D71E0F4Ceb33C3C59e9",
           "locator": "evm-fireblocks-custodial:0x92bbE9813D88F36Cb7Fd2D71E0F4Ceb33C3C59e9"
       }
   },
   "address": "0x3Ece49857cbB0DFFcbAf5eE9e5850e94eceBAb2f",
   "createdAt": "2025-02-03T22:48:45.707Z"
}

5

Interact with Your Wallet

First, let’s get some test USDC to work with. Visit Crossmint Testnet USDXM Faucet and paste your wallet address from step 4 to receive test USDC tokens in your chain of choice.

Now that you have some tokens, let’s check the wallet’s balance:

checkBalance.ts

const apiKey = "YOUR_API_KEY";
const walletAddress = "YOUR_WALLET_ADDRESS"; // From step 4
const tokens = ["eth", "usdc", "usdxm"]; // Tokens to fetch balances for
const chains = ["base-sepolia", "polygon-amoy"]; // Chains to query balances from

async function getWalletBalance() {
    const url = new URL(`https://staging.crossmint.com/api/v1-alpha2/wallets/${walletAddress}/balances`);
    url.search = new URLSearchParams({
        tokens: tokens.join(','),
        chains: chains.join(',')
    }).toString();

    const response = await fetch(url, {
        method: "GET",
        headers: {
            "X-API-KEY": apiKey,
            "Content-Type": "application/json",
        },
    });

    return await response.json();
}

getWalletBalance()
    .then((json) => console.log(json))
    .catch((err) => console.error(`error: ${err}`));

More info

What does this API do behind the scenes?

1. Creates a wallet of your chosen type on the specified blockchain

2. Sets up the appropriate signing mechanism (MPC, smart contract, etc.)

3. If specified, links the wallet to a user identity

Pre-generate wallets associated with a user

You can create wallets linked to users by adding a linkedUser parameter with a user identifier:

{
    // ... other wallet creation parameters ...
    linkedUser: "email:[e-mail]"
    // OR
    linkedUser: "twitter:@username"
    // OR
    linkedUser: "phoneNumber:[phone]"
    // OR
    linkedUser: "userId:your-internal-user-id"
}

Launching in Production

For production, the steps are almost identical, but some changes are required:

1. Create a developer account on the production console
2. Add credits to your account from Billing & Usage
3. Create a production key on the API Keys page with the same API scopes
4. Modify all code snippets to use https://www.crossmint.com instead of https://staging.crossmint.com

Learn More

Transfer Native Tokens

Send native tokens between wallets.

Transfer Tokens

Send ERC20 and other tokens.

Fetch Balance

Check wallet balances.

Fetch NFTs

Get NFTs owned by a wallet.

Dive into Advanced Topics

Delegated Keys

Spam Filters

Wallet UI Components

Error Handling

Other Links

API Reference

Deep dive into API reference docs.

Talk to an expert

Contact our sales team for support.