How It Works

Deposit flow

User enters amount
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Frontend POSTs { walletAddress, vaultId, amount }
to POST /api/v1/tx/deposit
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API fetches account sequence from Soroban RPC
builds invokeHostFunction calling vault.deposit(caller, amount, route_to)
simulates transaction to get resource footprint and fee
returns { xdr, fee }
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Frontend passes XDR to Freighter
User reviews and approves (sees: contract, function, amount, protocol)
Freighter returns signed XDR
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Frontend POSTs { xdr } to POST /api/v1/tx/submit
API forwards to Stellar RPC
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Transaction settles (~5 seconds)
Vault mints mUSDC shares to user's wallet

Withdraw flow

Symmetric to deposit. The user specifies a share amount (mUSDC), the API builds a vault.withdraw(caller, shares) invocation, Freighter signs, and the vault burns shares and returns USDC.

Rate selection

The API reads live APY data from two sources:

• Blend Capital pools via DeFiLlama's /pools endpoint, filtered to Stellar stablecoins and matched against a curated pool registry.
• DeFindex vaults via direct Soroban contract queries on testnet (currently returns estimated figures pending full integration).

The vault with the highest APY becomes bestVault. Its ID is passed to the deposit endpoint, which maps it to the Protocol enum (Blend or DeFindex) used by the vault contract.

Share pricing

The vault uses a proportional share model. When a user deposits:

shares_minted = deposit_amount * total_shares / vault_balance

If the vault has no outstanding shares, shares = amount (1:1 at genesis). As yield accrues and vault_balance grows relative to total_shares, the share price rises. Withdrawers receive:

usdc_out = shares_burned * vault_balance / total_shares

This means early depositors automatically benefit from yield without any claim or harvest action.

Security properties

• No server-side keys. The API returns unsigned XDR only. Private keys never leave Freighter.
• User-visible routing. The route_to parameter is part of the signed transaction. The user sees exactly which protocol their funds are going to before signing.
• On-chain state. USDC balances, share balances, and the active protocol are all stored in Soroban contract storage, auditable by anyone.