> For the complete documentation index, see [llms.txt](https://docs.channel360.co.za/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.channel360.co.za/api-usage/concepts/identifiers.md).

# Identifiers: which ID is which

Every ID you will meet in the Channel360 API, where it comes from and what to use it for.

The API and its webhook events use several IDs. This table says where each one comes from and what it is for.

| ID                                                     | Where you get it                                                           | What it identifies                          | Use it to                                                                                                                              |
| ------------------------------------------------------ | -------------------------------------------------------------------------- | ------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------- |
| Organisation ID                                        | The Organisation API URL in the web app                                    | Your organisation                           | Build every URL ([Authentication](/api-usage/get-started/authentication.md))                                                           |
| `notification._id`                                     | The `201` response from `POST /notification`; every `notification:*` event | One sent notification                       | Match delivery events to the send                                                                                                      |
| `msg_id`                                               | You choose it when sending                                                 | Your own reference                          | Find your order or record from an event                                                                                                |
| `appUser._id` (or `matchResult.appUser._id`)           | `message:appUser`; `notification:delivery:*` events                        | One customer on your WhatsApp number        | [Reply](/api-usage/reply-to-a-customer.md); match replies                                                                              |
| `conversation._id` (or `matchResult.conversation._id`) | The same events                                                            | The message thread with that customer       | [Match replies](/api-usage/match-replies-to-your-records.md) (preferred)                                                               |
| `destination.destinationId`                            | `notification:*` events                                                    | The phone number you sent to                | Find your record                                                                                                                       |
| `externalMessages[].id` (starts `wamid.`)              | `notification:delivery:*` events                                           | WhatsApp's own ID for the message           | Support queries with WhatsApp                                                                                                          |
| BSUID (for example `ZA.2c7a…`)                         | `client.externalId` on `message:appUser`, for username users               | A WhatsApp user who does not share a number | Recognise username users. It is not a phone number ([BSUID](/api-usage/match-replies-to-your-records/whatsapp-usernames-and-bsuid.md)) |
| `X-Channel360-Delivery-Id` header                      | Every webhook call                                                         | One webhook event (the same on retries)     | [Ignore duplicate deliveries](/api-usage/receive-delivery-updates.md)                                                                  |
| Template `id` and `name`                               | [List templates](/api-usage/manage-templates-through-the-api.md)           | A template                                  | `id` to update it; `name` to send it and to get one                                                                                    |

## Related

{% content-ref url="/pages/MMPfEfAxW2dosIuGBfym" %}
[Match replies to your records](/api-usage/match-replies-to-your-records.md)
{% endcontent-ref %}