Testnet: Sepolia
CoW Protocol is deployed on Sepolia for testing. All contracts share the same addresses as mainnet:
| Contract | Address |
|---|
| GPv2Settlement | 0x9008D19f58AAbD9eD0D60971565AA8510560ab41 |
| GPv2VaultRelayer | 0xC92E8bdf79f0507f65a392b0ab4667716BFE0110 |
API endpoint
https://api.cow.fi/sepolia/api/v1/
SDK configuration
import { SupportedChainId, TradingSdk } from '@cowprotocol/sdk-trading'
const sdk = new TradingSdk({
chainId: SupportedChainId.SEPOLIA,
appCode: 'my-app-testing',
}, {}, adapter)
Important: Sepolia has limited solver participation
Many solvers do not participate on Sepolia. This means:
- Orders may take longer to fill or expire unfilled
- Liquidity is thin — not all token pairs are tradeable
- Price quality is lower than mainnet
This is normal testnet behavior, not a bug in your integration. Tips for successful testnet orders
- Use wider limit prices — set slippage to 5-10% instead of the typical 0.5-1%
- Stick to common test pairs — WETH, USDC, and COW token have the most testnet liquidity
- Use longer validity — set
validFor to 1800+ seconds (30 min) to give solvers more batches
- Check the explorer — verify your order appears at
https://explorer.cow.fi/sepolia/orders/{uid}
Getting test tokens
Staging API (barn)
For testing against mainnet data without affecting production, use the staging (“barn”) API:
https://barn.api.cow.fi/mainnet/api/v1/
- Runs the same code as production, deployed ahead of releases
- Uses real mainnet tokens and liquidity
- Has a separate solver competition (solvers may behave differently)
- Is useful for testing mainnet integrations before going live
Orders submitted to barn are real orders on mainnet. They use real tokens and will settle on-chain if filled. Use barn for integration testing with small amounts, not as a sandbox.
SDK with barn
const parameters: TradeParameters = {
env: 'staging', // Uses barn API
kind: OrderKind.SELL,
// ... rest of parameters
}
Recommended testing workflow
- Start on Sepolia — verify your signing, order creation, and status polling logic works end-to-end
- Move to barn (mainnet staging) — test with real liquidity and solver competition using small amounts
- Go to production — switch to
api.cow.fi/mainnet with production amounts
Common testnet issues
| Issue | Cause | Fix |
|---|
| Order expires unfilled | Limited solvers on Sepolia | Widen slippage, use longer validity, try WETH/USDC pair |
NoLiquidity error | Token pair has no testnet pools | Use well-known test tokens (WETH, USDC) |
SellAmountDoesNotCoverFee | Gas costs high relative to small test amounts | Increase the sell amount |
Order shows presignaturePending | PreSign transaction not confirmed | Wait for Sepolia block confirmation, check tx hash |
| Different results than mainnet | Different solver set and liquidity | Expected — use barn for mainnet-equivalent testing |
