> ## Documentation Index
> Fetch the complete documentation index at: https://docs.thedatacity.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Response reference

> Every field the Company Matching API returns, what it contains, and when it is empty.

A successful match returns a JSON object with the fields below.

## Response fields

These fields are returned on `POST /match` and on each row in batch results.

| Field                    | Type           | When present                                        |
| ------------------------ | -------------- | --------------------------------------------------- |
| `input_name`             | string         | Always — echoed from the request                    |
| `id`                     | string \| null | Your optional row id, if you sent one               |
| `input_url`              | string \| null | Echoed if provided                                  |
| `postcode`               | string \| null | Echoed if provided                                  |
| `sic_code`               | string \| null | Echoed if provided                                  |
| `start_trading_date`     | string \| null | Echoed if provided                                  |
| `matched_company_number` | string \| null | Set when a match is found; otherwise `null`         |
| `matched_company_name`   | string \| null | Registered name for the matched CRN, when available |
| `active`                 | string \| null | Active / inactive (or equivalent) when known        |

A `200` with `matched_company_number: null` means the engine finished without a confident match. That is not an error.

### Example (matched)

```json theme={null}
{
  "input_name": "Sainsbury's Supermarkets Ltd",
  "id": "demo-sainsburys",
  "input_url": null,
  "postcode": null,
  "sic_code": null,
  "start_trading_date": null,
  "matched_company_number": "3261722",
  "matched_company_name": "SAINSBURY'S SUPERMARKETS LTD",
  "active": "Active"
}
```

### Example (unmatched)

```json theme={null}
{
  "input_name": "Completely Unknown Trading Style XYZ",
  "id": "row-42",
  "matched_company_number": null,
  "matched_company_name": null,
  "active": null
}
```

## Request body fields

| Field                | Required | Notes                                           |
| -------------------- | -------- | ----------------------------------------------- |
| `input_name`         | Yes      | 1–512 characters                                |
| `input_url`          | No       | Website URL (up to 2048 characters)             |
| `postcode`           | No       | Improves match scoring                          |
| `sic_code`           | No       | Improves match scoring                          |
| `start_trading_date` | No       | Improves match scoring; a year string is enough |
| `id`                 | No       | Your correlation id (up to 128 characters)      |

Null optional fields may be omitted from the request; the API does not require them.