# Fund apps and earn on stablecoins

> One-click deposits into Polymarket, Hyperliquid, Aave or any deposit address from any chain and token, and the best USDC / USDT supply rates across Aave, Compound, Morpho and Spark with user-signed deposits.

Source: https://docs.layerhop.com/guides/fund-and-earn

Two read-only API groups power app.layerhop.com/fund and app.layerhop.com/earn, and you can use them in your own app. LayerHop never holds the funds: the route is an ordinary quote the user signs, and a vault deposit is a pair of calls the user's own wallet sends. LayerHop doesn't control these apps or protocols, so show each target's `risk` text before the user signs.

## Which apps can a user fund?

`GET /v1/fund/targets` lists them, with where the money lands and who receives it:

| Target | `kind` | Route lands as | Recipient |
|---|---|---|---|
| `polymarket` | `bridge-address` | USDC on Polygon | the user's Polymarket bridge address (below); min $2 |
| `hyperliquid` | `own-account` | USDC on Hyperliquid (HyperCore, chain 1337) | the user's own EVM address |
| `aave-v3-base`, `aave-v3-arbitrum` | `vault` | USDC on Base / Arbitrum | the user's wallet, then a supply from it |
| `deposit-address` | `custom-address` | the chain and token the app asks for | the address the user pastes |

For every target, get a quote from the user's token to `dst` with `recipient` set as above, and add `purpose=fund` if you want the orders tagged.

## How does the Polymarket deposit work?

Polymarket's Bridge API gives every Polymarket wallet its own bridge address, and a deposit to it credits that Polymarket balance. `POST /v1/fund/polymarket/address {address}` asks Polymarket for it (with your builder code when `POLYMARKET_BUILDER_CODE` is set) and returns `{ wallet, evm, svm? }`. Quote any token into USDC on Polygon with `recipient = evm`. The `address` you send must be the user's own Polymarket wallet (shown in their Polymarket profile), not their connected wallet and never an exchange address. Deposits under $2 are not processed by Polymarket.

## What are the current stablecoin rates?

`GET /v1/yields?asset=USDC` (or `USDT`) lists a fixed registry of major vaults, best first: Aave v3, Compound v3, Morpho vaults (Spark USDC, Gauntlet USDC Prime, Steakhouse) and Spark Savings USDC. Aave, Compound and Spark rates are read on-chain; Morpho APYs come from Morpho's API, after the curator fee. Every vault's address and deposit were checked against mainnet state before it was added. Rates are variable and cached for 5 minutes; a vault whose rate can't be read is listed in `unavailable`.

The app ranks the pools by a year of yield at today's rate for the user's amount, minus the one-off cost of getting there (route fees and gas from the user's largest balance of that stablecoin; nothing when it is already on that chain), so a slightly lower rate on the chain you're on can win for a small amount.

## How does a vault deposit work?

1. Route to the vault's stablecoin on its chain, paid to the user's own wallet (skip this when it is already there).
2. `POST /v1/yields/{id}/deposit {owner, amount}` returns the calls: an exact-amount `approve` and then `supply` (Aave v3, to `owner`), `supply` (Compound v3) or `deposit(amount, owner)` (ERC-4626 vaults). The API simulates them from `owner` with `eth_simulateV1` first; a revert is `CALLS_REVERTED`.
3. Send the calls from `owner`. With `@layerhop/wagmi`, `sendWalletCalls` puts approve and deposit in one EIP-5792 confirmation where the wallet batches atomically, and sends them one after the other otherwise.

For Aave, `oneStep: true` on the target means destination calls are live: a `POST /v1/quote` with `action: { type: "aave-v3-supply" }` bridges and supplies in one transaction (see [destination calls](/guides/destination-calls)).

## Can it move my money when another vault pays more?

No. Moving funds automatically would need custody. Instead, a rate alert (`kind: yield` in [`POST /v1/alerts/drafts`](/api-reference#create-a-telegram-alert-draft)) tells the user on Telegram when the best other vault pays at least `pct` APY points more than theirs, with a link back to app.layerhop.com/earn. Moving is always the user's own click and signature.

## Related

- [Destination calls](/guides/destination-calls)
- [Hyperliquid deposits](/guides/hyperliquid)
- [Wallet integrations](/guides/wallets)