# POST /api/v1/credit/loans/{loan_id}/adjustments

> Adjust a loan

- **Tag:** credit
- **Operation ID:** `create_loan_adjustment`

## Description

Waive part of a loan's unpaid fee (`waive_fee`) or accrued interest (`waive_interest`), or credit its unpaid principal as goodwill (`goodwill_credit`). The amount may not exceed what is outstanding in that bucket. Posts an `adjustment` ledger entry with the reason as its memo and, when the program posts to the GL, a journal entry to Fee Waivers, Interest Waivers or Goodwill Credits. A loan brought to zero is paid on `effective_on` and emits `credit.loan.paid`. Operator action: API tokens receive 403.

## Authentication

Bearer token in `Authorization` header.
Required header: `x-business-id: <business uuid>`.

## Parameters

- `loan_id` (path, string, required)

## Request body

Schema: `CreditLoanAdjustmentRequest`

- `type` (string · required) (one of: waive_fee, waive_interest, goodwill_credit) — waive_fee reduces the unpaid disbursement fee, waive_interest the unpaid accrued interest, goodwill_credit the unpaid principal.
- `amount_cents` (integer · required) — At most what is outstanding in that bucket; more is refused.
- `reason` (string · required) — Why. Recorded on the adjustment and as the ledger memo.
- `effective_on` (string · date) — The date the reduction counts from. Defaults to today; not before the loan was originated, and not in the future.

## Responses

### 201 — Successful Response

Schema: `SuccessEnvelope_CreditLoanAdjustmentResult_`

- `success` (boolean)
- `message` (string)
- `code` (string)
- `data` (CreditLoanAdjustmentResult)

### 400 — Bad Request - Invalid input

Schema: `ErrorResponse`

- `error` (string · required) — Error category: `validation_error`, `unauthorized`, `forbidden`, `not_found`, `conflict`, `rate_limited`, `server_error`, or `service_unavailable`.
- `message` (string · required) — Human-readable explanation, safe to show to end users.
- `code` (string · required) — Stable machine-readable code in `CATEGORY_NNN` form (e.g. `NOT_FOUND_006`, `AUTH_010`, `GEN_002`).
- `request_id` (string) — Correlation id for support requests. Echoes the `x-request-id` request header when one was supplied.
- `errors` (object) — Field-level validation messages keyed by field name. Present on 400/422 validation failures only.

### 401 — Unauthorized - Missing or expired token, an MCP OAuth token used against the REST API, or no access to this business

Schema: `ErrorResponse`

- `error` (string · required) — Error category: `validation_error`, `unauthorized`, `forbidden`, `not_found`, `conflict`, `rate_limited`, `server_error`, or `service_unavailable`.
- `message` (string · required) — Human-readable explanation, safe to show to end users.
- `code` (string · required) — Stable machine-readable code in `CATEGORY_NNN` form (e.g. `NOT_FOUND_006`, `AUTH_010`, `GEN_002`).
- `request_id` (string) — Correlation id for support requests. Echoes the `x-request-id` request header when one was supplied.
- `errors` (object) — Field-level validation messages keyed by field name. Present on 400/422 validation failures only.

### 403 — Forbidden - Insufficient permissions

Schema: `ErrorResponse`

- `error` (string · required) — Error category: `validation_error`, `unauthorized`, `forbidden`, `not_found`, `conflict`, `rate_limited`, `server_error`, or `service_unavailable`.
- `message` (string · required) — Human-readable explanation, safe to show to end users.
- `code` (string · required) — Stable machine-readable code in `CATEGORY_NNN` form (e.g. `NOT_FOUND_006`, `AUTH_010`, `GEN_002`).
- `request_id` (string) — Correlation id for support requests. Echoes the `x-request-id` request header when one was supplied.
- `errors` (object) — Field-level validation messages keyed by field name. Present on 400/422 validation failures only.

### 404 — Not Found - Resource does not exist

Schema: `ErrorResponse`

- `error` (string · required) — Error category: `validation_error`, `unauthorized`, `forbidden`, `not_found`, `conflict`, `rate_limited`, `server_error`, or `service_unavailable`.
- `message` (string · required) — Human-readable explanation, safe to show to end users.
- `code` (string · required) — Stable machine-readable code in `CATEGORY_NNN` form (e.g. `NOT_FOUND_006`, `AUTH_010`, `GEN_002`).
- `request_id` (string) — Correlation id for support requests. Echoes the `x-request-id` request header when one was supplied.
- `errors` (object) — Field-level validation messages keyed by field name. Present on 400/422 validation failures only.

### 422 — Validation Error

Schema: `ErrorResponse`

- `error` (string · required) — Error category: `validation_error`, `unauthorized`, `forbidden`, `not_found`, `conflict`, `rate_limited`, `server_error`, or `service_unavailable`.
- `message` (string · required) — Human-readable explanation, safe to show to end users.
- `code` (string · required) — Stable machine-readable code in `CATEGORY_NNN` form (e.g. `NOT_FOUND_006`, `AUTH_010`, `GEN_002`).
- `request_id` (string) — Correlation id for support requests. Echoes the `x-request-id` request header when one was supplied.
- `errors` (object) — Field-level validation messages keyed by field name. Present on 400/422 validation failures only.

## Code samples

### cURL

```bash
curl -X POST 'https://api.ondayzero.com/api/v1/credit/loans/{loan_id}/adjustments' \
  -H 'Authorization: Bearer dz_your_token' \
  -H 'x-business-id: YOUR_BUSINESS_ID' \
  -H 'Content-Type: application/json' \
  -d '{
  "type": "waive_fee",
  "amount_cents": 0,
  "reason": "string"
}'
```

### JavaScript

```javascript
const response = await fetch('https://api.ondayzero.com/api/v1/credit/loans/{loan_id}/adjustments', {
  method: 'POST',
  headers: {
    Authorization: 'Bearer dz_your_token',
    'x-business-id': 'YOUR_BUSINESS_ID',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
  "type": "waive_fee",
  "amount_cents": 0,
  "reason": "string"
}),
});
const data = await response.json();
```

### Python

```python
import httpx

headers = {
    "Authorization": "Bearer dz_your_token",
    "x-business-id": "YOUR_BUSINESS_ID",
}

payload = {'type': 'waive_fee', 'amount_cents': 0, 'reason': 'string'}

response = httpx.post("https://api.ondayzero.com/api/v1/credit/loans/{loan_id}/adjustments", headers=headers, json=payload)
data = response.json()
```

## See also

- HTML version: https://www.ondayzero.com/docs/reference/credit/create-loan-adjustment
- OpenAPI slice: https://www.ondayzero.com/docs/reference/credit/create-loan-adjustment/openapi.json
- Other endpoints in **credit**: https://www.ondayzero.com/docs/reference/credit (markdown bundle: https://www.ondayzero.com/docs/reference/credit.md, OpenAPI: https://www.ondayzero.com/docs/reference/credit/openapi.json)
- Endpoint catalog: https://www.ondayzero.com/docs/reference/index.md