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

# Using the API

### Introduction

<Tip>Are you missing a feature? Please use our [Feature Board](https://insigh.to/b/instant-rest-api) to add a suggestion or upvote existing features. Sign up to the [waitlist](/api-reference/auth/overview) to get notified of future updates and releases.</Tip>

### Good to know

* BaseURL of the API is [https://instantrestapi.com/api/](https://instantrestapi.com/api/)
* The resource name can be anything that is accepted in a URL path (such as `invoices` or `customers`, except in the website test playground - it is fixed to `resources`).
* `api/temporary-key` and `api/waitlist` endpoints are restricted and can only be used as described in the [authentication section](/api-reference/auth/overview).
* All resources created are scoped to an API key and can only be accessed using that specific key.

### Creating a resource

Create a resource simply by POSTing a JSON object to the API URL followed by the name of your resource.
For example: to create a new invoice, send a POST request to the `api/invoices` endpoint with a request body of the invoice object.
The following requirements must be met:

* Header `Content-Type` must be `application/json`
* Body must not be empty
* Body must be a valid JSON
* Body must contain `id` field
* Body must be less than 1mb

<Note>POST & PUT are functionally the same, both will "upsert" the object for the specifid id.</Note>

### Filtering & Searching

The API does not **currently** support filtering or searching of resources.

### Schema

As long as the request body contains a valid JSON object, it will be accepted.

<Note>All objects must include a property with name `id` that is the unique identifier.</Note>

The API does not **currently** support indexes or constraints.

### Relationships

The API does not **currently** support any type of relationship between resources.
Instead, you may choose one of the following 2 options.

**1. Embedding related resources**

The easiest strategy is to embed the related resources inside the top level resource. For example, you can embed a customer object or invoice lines in the invoice object as shown below:

```json theme={null}
{
    "id": "1",
    "invoiceNumber": "12345",
    "amount": 100.00,
    "customer": {
        "id": "1",
        "firstName": "John",
        "lastName": "Doe",
    },
    "invoiceLines": [
        {
            "id": "1",
            "description": "Product 1",
            "quantity": 1,
            "unitPrice": 100.00
        }
    ]
}
```

Any time a customer or invoiceLine is updated, you must also update the whole invoice object to reflect the changes.

**2. Embedding ids**

Alternatively, you can embed references to other resources by `id` if you keep track of relationsship updates client side.

For example, consider the below:

<CodeGroup>
  ```json api/invoices/1 theme={null}
  {
      "id": "1",
      "invoiceNumber": "12345",
      "amount": 100.00,
      "customerId": "1",
      "invoiceLineIds": ["1"]
  }
  ```

  ```json api/customers/1 theme={null}
  {
      "id": "1",
      "firstName": "John",
      "lastName": "Doe",
  }
  ```

  ```json api/invoicelines/1 theme={null}
  {
      "id": "1",
      "description": "Product 1",
      "quantity": 1,
      "unitPrice": 100.00
  }
  ```
</CodeGroup>

So if you request a `DELETE` on `api/invoicelines/1`, you must also do a `PUT` on `api/invoices/1` and remove the invoiceline from `invoiceLineIds` array.

### Subresources

The API does not **currently** support subresources. So for example, you cannot create/get an invoice line by sending a POST/GET request to `api/invoices/1/invoicelines/1`.