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 Cost Estimate
3. Requesting a Final Borrow Quote and Credit Authorization
4. Check out the Fill Optimization Tips

1. Stash Fill Lifecycle

2. Request a Credit Borrow Cost Estimate (Optional)

Call the Borrow Cost API to preview an estimated borrowing cost for a potential fill before requesting credit.

Fetch Borrow Cost Estimate 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 of deposit
      caller: "address", // the address that will execute the borrow and fill ond destChainId
    },
  },
);

3. Request a Final Borrow Quote

If proceeding to fill with Sprinter Stash, call the Borrow Quote API to request a borrow quote to reserve credit and authorize the fill. This can be based on input or output amount.

Request Final Borrow Quote 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 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);

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.