Stash API quick start

tip

Request your Stash API key via Sprinter Stash Request or contacting support@sprinter.tech

As a Solver

Sprinter Stash enables solvers to borrow crosschain credit on-demand to execute user intents without needing pre-funded inventory.

This guide covers:

1. Recap of the Stash Fill Lifecycle
2. Requesting a Credit Borrow Quote Estimate
3. Requesting a Final Borrow Cost and Credit Authorization
4. Check out the Fill Optimization Tips

1. Stash Fill Lifecycle

2. Request a Credit Borrow Quote Estimate (Optional)

Call the Borrow Quote API to preview an estimated borrowing cost for a potential fill before requesting credit. This can be based on input or output amount.

Request Borrow Quote Estimate with type ExactInput (input amount - borrow costs)

const baseUrl = "https://api.sprinter.tech";
const sourceChainId = "eip155:8453"; // eip155:8453(Base), eip155:10 (Optimism), eip155:42161 (Arbitrum). ChainId must use capid format from our configuration
const protocol = "across"; // "across" or "mayan"
const type = "ExactInput"; // Request will consider the amount as (input amount - borrow costs)
const amount = 10000000; // This is the ExactInput eg 1 USDC (6 decimals)
const response = await fetch(
  `${baseUrl}/liquidity/chain/${sourceChainId}/protocol/${protocol}/type/${type}/quote`,
  {
    method: "GET",
    headers: {
      "X-Auth-Token": "<your_api_key>",
    },
    body: {
      amount: amount,
      token: "destination_token_address", // Token address
      network: "eip155:10", // Destination_Chain_ID
    },
  },
);

const borrowQuote = await response.json();
console.log("Expected amount:", borrowQuote.expectedOutput);
console.log("Borrow Cost:", borrowQuote.borrowCost);

Request Final Borrow Quote Estimate with type ExactOutput (output amount + borrow costs)

const baseUrl = "https://api.sprinter.tech";
const sourceChainId = "eip155:8453"; // eip155:8453(Base), eip155:10 (Optimism), eip155:42161 (Arbitrum). ChainId must use capid format from our configuration
const protocol = "across"; // "across" or "mayan"
const type = "ExactOutput"; // Request will consider the amount as (output amount + borrow costs)
const amount = 10000000; // This is the ExactInput eg 1 USDC (6 decimals)
const response = await fetch(
  `${baseUrl}/liquidity/chain/${sourceChainId}/protocol/${protocol}/type/${type}/quote`,
  {
    method: "GET",
    headers: {
      "X-Auth-Token": "<your_api_key>",
    },
    body: {
      amount: amount,
      token: "destination_token_address", // Token address
      network: "eip155:10", // Destination_Chiain_ID
    },
  },
);

const borrowQuote = await response.json();

console.log("Expected Input:", borrowQuote.requiredInput);
console.log("Borrow Cost:", borrowQuote.borrowCost);

3. Request the final Credit Borrow Cost

If proceeding to fill with Sprinter Stash, call the Borrow Cost API to request the final borrow cost to reserve credit and authorize the fill.

Fetch Borrow Cost Example Payload

const baseUrl = "https://api.sprinter.tech";
const destChainId = "eip155:8453"; // eip155:8453(Base), eip155:10 (Optimism), eip155:42161 (Arbitrum) destChainId must use capid format from our configuration
const protocol = "across"; // "across" or "mayan"
const txHash = "string"; // Source chain deposit TX
const response = await fetch(
  `${baseUrl}/liquidity/chain/${destChainId}/protocol/${protocol}/deposit/${txHash}/requests`,
  {
    method: "GET",
    headers: {
      "X-Auth-Token": "<your_api_key>",
    },
    body: {
      input: "callData", // encoded callData for destination ( Borrow & Fill) it also contains depositData prams for MPC validation
      caller: "address", // the address that will execute the borrow and fill ond destChainId
    },
  },
);

4. Fill Optimization Tips

Here are some tips on getting the best performance and profit from your Sprinter Stash integration:

1. Pre-fetch Borrow Cost - Call GET /type/{type}/quote as early as possible (when detecting intents) to evaluate solver profitability.

2. Batch Gas Where Possible - Bundle execution and repayment transactions to reduce gas costs.

3. Optimize for Slippage - Query quotes close to execution time to reduce stale pricing or slippage-induced fills.

4. Handling Rate Limits - If you hit 429s, give it a moment and retry using retry_after value. You can request higher limits via support@sprinter.tech.

5. Validate Transaction Hash Early - Ensure the user intent transaction is final and not reverted before calling /deposit/{txHash}/request.