DeFi Routing for Developers: Integration & API Guide
Plan a DeFi routing integration with token validation, quote handling, explicit approvals, transaction simulation, receipts, and recovery states.
Design the lifecycle before the API call
A routing integration is more than a button that requests calldata. It must turn a user’s intent into a validated request, explain the resulting quote, obtain the right authorization, submit the transaction, and report the eventual outcome accurately.
Start by identifying supported chains, assets, execution models, and required provider credentials. Keep secret API credentials out of public browser code. DeFiRouter’s developer pages are educational integration guides; this website does not issue API keys or operate an endpoint.
Validate request identity and units
Use chain IDs and exact contract addresses or mints. Handle base units with appropriate integer precision and verify token decimals from a trusted source. Keep native assets and wrapped representations distinct. Reject invalid amounts and incompatible chains before requesting a quote.
Bind every response to the specific request that produced it. An old quote arriving late must not replace a newer selection. If the user changes the account, network, amount, or token, invalidate dependent state rather than carrying assumptions into a different transaction.
Keep the integration states explicit
| State | What the application should establish |
|---|---|
| Quote requested | The request belongs to the current account, network, assets, and amount. |
| Quote available | The output, fees, minimum received, timing conditions, and issues are understood. |
| Permission needed | The documented spender and required allowance are independently verified. |
| Ready to sign | The transaction target, recipient, value, and encoded actions match the intended route. |
| Submitted | A transaction identifier exists; execution success has not yet been established. |
| Confirmed or failed | The receipt, relevant events, and resulting asset movement support the reported outcome. |
Verify permissions and transaction destinations separately
The address that receives an allowance is not necessarily the destination of the execution transaction. Use the provider’s documented contract set and response fields for the selected chain. Never assume that an arbitrary target returned in a quote is an appropriate spender.
Support user rejection, an insufficient allowance, an approval that fails, and a quote that becomes invalid after approval. Re-fetch and re-check as required by the provider’s lifecycle rather than submitting stale assumptions. Read the approval guide for the user-facing implications.
Simulation and reconciliation deserve first-class treatment
Where the stack supports it, simulate the intended transaction and explain actionable errors. Simulation is a view of a particular state, not a promise of future success. Changing liquidity, balances, permissions, or network conditions can still alter the result.
After submission, handle pending, replaced, dropped, reverted, and confirmed states according to the chain and wallet interface. Store enough non-sensitive context to reconcile the receipt with the original intent. Cross-chain workflows require additional delivery and settlement states.
A useful place to start
The complete API integration checklist covers quote lifecycles, authorization, controls, and recovery. Combine it with the fintech integration guide when you need account reconciliation and operational support processes.