> For the complete documentation index, see [llms.txt](https://docs.nansen.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.nansen.ai/api/changelog/08-10-2026-error-responses-credits-used.md).

# 08-10-2026: Error Responses Report X-Nansen-Credits-Used: 0

Credits are deducted only for successful (2xx) responses. Until now, an error response from a paid endpoint carried `X-Nansen-Credits-Cost` but no `X-Nansen-Credits-Used`, which made it hard to tell whether the request was charged.

**Every non-2xx response that carries `X-Nansen-Credits-Cost` now also carries `X-Nansen-Credits-Used: 0`.** This includes `422` validation errors and `500` errors. Requests rejected before pricing may carry neither header. `X-Nansen-Credits-Remaining` is sent when an account balance is available, including credit-checked successful responses and insufficient-credit `403` responses.

**Blocked-token `422` errors now name the rejected field.** When a token is not supported on an endpoint (for example Solana USDC or native SOL on `POST /api/v1/tgm/dex-trades`), the error used to report `errors[].field` as `body` and no `param`. It now reports the field that holds the address:

|                  | Before | Now                  |
| ---------------- | ------ | -------------------- |
| `param`          | `null` | `token_address`      |
| `errors[].field` | `body` | `body.token_address` |

The same change applies to every endpoint that rejects a specific token or native-token address, for example `tgm/transfers`, `tgm/jup-dca`, `tgm/flows`, `tgm/pnl-leaderboard` and `profiler/address/counterparties` (where it names the wallet field you sent, such as `wallet_addresses[1]`). The status code, `code` and message do not change.


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