The core flow for integrating the OKX cross-chain API is straightforward: use /quote to get a quote and route, use /build-tx (or the SDK's execute method) to build and send the transaction, then use /status to check the final state by the source chain txhash. The parts that actually trip people up are not in the main flow but in two areas: the routerList returned by the quote may be empty (no direct route), and settlement status advances in stages — every intermediate state before SUCCESS does not mean the funds have arrived on the destination chain.
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Quotes: First Confirm a Route Exists, Then Choose Which One
When calling the cross-chain quote endpoint, the returned routerList is a multi-bridge list. Each record contains the bridge name, estimated received amount, minimum received amount, cross-chain fee, estimated time, and whether approval is required. The bridgeId is a key identifier that must be reused for later execution and status queries. It must come from the quote result and should not be hardcoded.
A common mistake is assuming that a successful quote means you can execute. If routerList is empty, it means there is no direct route between the current chain pair. The backend may return a fallback object. In this case, you should not continue with the execution flow. Instead, consider switching chain pairs or using a relay route. Whether a chain pair supports cross-chain transfers should be confirmed beforehand using the supported bridge list endpoint, rather than only realizing there is a problem when the quote returns an empty list.
The reliability of the needApprove field is conditional: it is only trustworthy when the quote request explicitly asks to check approval. If you did not pass this parameter, the needApprove you see may be a default value and cannot be used as a basis for deciding whether to approve first. For tokens like USDT that require revoking before re-approving, the needCancelApprove field may be true, but the backend does not always return it. You need to judge based on the token type yourself.
Settlement: status Is Not detailStatus
When querying cross-chain status, the response contains two status fields with different purposes.
status has only three values: PENDING (in progress), SUCCESS (success), and FAILURE (failure). This is a rough terminal-state indicator. But what actually tells you "where the money is" is detailStatus. Its values include WAITING, FROM_SUCCESS, BRIDGE_PENDING, BRIDGE_SUCCESS, SUCCESS, REFUND, and others.
The key point is this: FROM_SUCCESS only means the source chain transaction succeeded. It does not mean the cross-chain bridge has processed it, and it certainly does not mean the destination chain has received the funds. BRIDGE_SUCCESS means the bridge side is done, but the final credit on the destination chain may still be on its way. Only when detailStatus reaches SUCCESS will toTxHash and toAmount have valid values. If your application needs to trigger follow-up actions after settlement (such as notifying users, recording transactions, or releasing services), you should wait for detailStatus === SUCCESS, not act early on any intermediate signal other than status becoming SUCCESS.
The REFUND state needs separate handling. It means the cross-chain transfer failed and the funds were returned to the source chain. In this case, the refundTxHash field will have a value. You can guide users to check the refund on the source chain explorer. Do not confuse REFUND with FAILURE: FAILURE means failure with no refund information (or the refund has not happened yet), while REFUND means failure but the refund has already been processed.
Exception Recovery: Handle by Stage
The first step in exception recovery is to determine which stage the failure occurred in. A source chain transaction that never went out (signature rejected, insufficient balance, approve failed) is handled very differently from a source chain transaction that succeeded but got stuck at the bridge.
Source chain transaction failed to send: The most common causes are insufficient balance or insufficient gas. The SDK's error handling categorizes these cases. insufficient_balance and insufficient_gas should directly tell the user to add funds, not retry. execution reverted means the contract call was rolled back. You need to check whether the transaction parameters (amount, slippage, token address) match those at quote time. Slippage exceeding the limit is also a common cause. The slippage tolerance in the cross-chain quote needs to match the execution settings. Otherwise, a transaction that passed at quote time may be rejected at execution time.
Source chain transaction succeeded but cross-chain not completed: In this case, you already have a txhash. Do not send the transaction again. Instead, keep querying with /status and use detailStatus to decide whether to keep waiting or whether the refund process has begun. The processing time of a cross-chain bridge depends on the specific bridge. The estimateTime in OKX's quote is a seconds-level estimate, but it is only an estimate, not a promise. If it remains BRIDGE_PENDING long past estimateTime, you can check whether the bridge has known delays, but the remedies on the user side are limited — the funds are already on the bridge. What you can do is wait or contact OKX DEX support.
At the SDK level, there is a configurable retry mechanism: HTTP request failures are retried up to 3 times by default, with linear intervals (1 second, 2 seconds, 3 seconds). This retry only covers transient network-level failures, not business logic errors. If the error is 429 (rate limited), the retry interval may need to be longer. The SDK's test code uses a more aggressive backoff strategy for rate-limit scenarios. For production integration, it is recommended to set reasonable retry limits separately for quote and status queries, and avoid dense retries when rate limited.
Integration Recommendations
If your application only occasionally initiates cross-chain transfers (for example, user-triggered manually), the REST API alone is enough. /quote → /build-tx → sign and send → poll /status — four steps are sufficient. The value of the SDK lies in encapsulating signing and retries. But if you already have your own on-chain transaction sending logic, introducing the SDK adds an extra layer of dependency.
If you are building high-frequency or automated cross-chain routing (such as a wallet's built-in swap feature), you need to seriously handle multi-route selection in routerList and quote freshness. There is a time gap between when the quote is returned and when the user confirms execution. The price may have already changed. OKX's quote endpoint itself does not enforce price locking. The actual execution price is determined on-chain. On the user confirmation page, minimumReceived is more worth highlighting than toTokenAmount, because the former is the minimum amount the user can receive under slippage protection.
The frequency of status polling needs to be controlled. The /status endpoint does not have an explicit rate limit in the documentation, but as a query endpoint, excessive polling may trigger rate limiting. A reasonable approach is to start querying after the source chain transaction is confirmed, with intervals gradually lengthening from a few seconds, rather than fixed high-frequency requests. Stop after reaching SUCCESS or REFUND.
If you do not have an OKX account yet, when registering with the invitation code 24U2795 from this site, the referrer field is in the registration form and is optional. Using the cross-chain API requires separately applying for developer credentials (API Key, Secret, Passphrase, Project ID), which is unrelated to the referral relationship of a regular account registration.
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