400 No path found | No route exists between the two assets for that amount, with the venues in protocols | Add venues to protocols, try a smaller amount, or check that both assets have liquidity |
400 Invalid Stellar address | assetIn or assetOut is not a valid Stellar address | Send contract addresses (C...) |
400 amount must be a positive integer number of stroops | amount is zero, negative or has decimals | Send the amount in the asset’s smallest unit, as a string |
400 sdex is not available for contract (C) addresses | from or to is a contract and sdex was the only venue | Add a Soroban venue to protocols; see Routing through SDEX |
400 Simulation Failed | The transaction fails when simulated, for example for lack of balance | Read errorCode and extra, fix the account state and build again |
400 Transaction Failed | /send submitted the transaction and the network rejected it | Read detail and extra; quote and build again before retrying |
| 403 | The API key is missing, malformed or revoked, or the route needs a role your key does not have | Send Authorization: Bearer sk_... with an active key. The API answers 403, never 401 |
409 Quote stale | The quote passed to /quote/build no longer matches the fee in force or its own amounts | Quote again and build from the new quote |
428 CREATE_TRUSTLINE | The receiving account has no trustline for the output asset | Sign and submit the transaction in actionData.xdr, then build again, or use Gasless Trustline |
| 429 | You are over your plan’s request rate | Wait Retry-After seconds; see Plans and rate limits |
503 Routing unavailable | The routing service could not answer | Retry with backoff. It is temporary, not a property of the pair |
