# Improved API Error Codes (/docs/changelog/active-notifications/improved-api-error-codes)

Posted: August 20, 2026 | Effective: September 4, 2026

Additional HTTP 404 error codes that provide more informative error reasons are being added to the `/quote` endpoint of the API.

**What is changing?**

When a `/quote` request returns an HTTP 404, the response will include more specific `errorCode` values and a `detail` field.

| `errorCode`                        | Meaning                                                                                       | Retry?              |
| ---------------------------------- | --------------------------------------------------------------------------------------------- | ------------------- |
| `QuoteAmountTooLowError`           | Below the minimum quotable size for the requested protocol (e.g. UniswapX per-chain minimums) | No                  |
| `NoRouteFoundError`                | Routing completed, but no viable route was found                                              | No                  |
| `UnsupportedTokenError`            | Token is not routable (e.g. unknown, blocklisted, or on the wrong chain)                      | No                  |
| `UnsupportedChainError`            | Chain is not supported for the requested operation                                            | No                  |
| `UniswapXNotSupportedOnChainError` | The requested UniswapX variant is not supported on this chain                                 | No                  |
| `UpstreamTimeoutError`             | A routing dependency timed out or errored; it is unknown whether a route exists               | Yes                 |
| `ResourceNotFound` (fallback)      | Unclassified failure                                                                          | Yes (conditionally) |

For clarity, the HTTP 404 error structure is not changing and will continue to look like:

```json
{
  "errorCode": "UnsupportedTokenError",
  "detail": "Token not routable (unknown / blocklisted / wrong chain)",
  "requestId": "a00382a5539523928a4f997974dd27eb"
}
```

**Why is this changing?**

Except for field-level validation errors, the `/quote` endpoint usually returned an `errorCode` of `ResourceNotFound` when it could not return a quote. This catch-all error was not specific enough for integrators to tell users whether to retry the request or change its parameters.

**What do I need to do?**

If you parse the `errorCode` field for specific actions or display, add handling for the new error codes. We also recommend a default case so your integration can tolerate additional error codes in the future.

If you pass through the `detail` field from an HTTP 404 response to your users or interface, no change is needed.