API - Overview and Quick Start

The API lets your own website, app or script read and change the data in your account: customers, leads, inventory, payments and more. This article explains how it works from the ground up and links to the article for each endpoint. If you are new to the API, start here.

Before You Start

1. Activate the API & WordPress module under Settings > Subscription.
2. Create an API key and give it the permissions your integration needs. See API - Setup Access.
3. Know the costs. The first 500 API calls each month are free. After that, calls are billed. See API - Transaction Charges.

Your First Call

Paste this into a terminal, with your own key in place of YOUR_API_KEY. It asks for the first two items in your inventory.

curl "https://rental.software/api6/rentals?apiKey=YOUR_API_KEY&limit=2"

You can also open the same URL in a web browser. If the key works, you get JSON back:

{
  "offset": 0,
  "limit": "2",
  "count": "127",
  "first": "https://rental.software/api6/rentals?offset=0&limit=2",
  "next": "https://rental.software/api6/rentals?offset=2&limit=2",
  "previous": "https://rental.software/api6/rentals?offset=0&limit=2",
  "items": [
    { "id": "336198", "ridename": "10x10 Tent" },
    { "id": "336199", "ridename": "11 x 11 Castle Jumper" }
  ],
  "request_time": 1760000000
}

(The items are shortened here.) If you get an error instead, look it up in API - Errors and Rate Limits.

How Requests Work

The URL

Every URL starts with the base URL, followed by the name of an endpoint, and sometimes the ID of one record:

https://rental.software/api6/{endpoint}
https://rental.software/api6/{endpoint}/{id}

For example, /api6/customers is the list of customers and /api6/customers/533261 is one customer.

The HTTP Method

Each endpoint article says which methods it accepts. Using a method an endpoint does not accept returns HTTP 405.

The API Key

Send your key in a parameter named apiKey (with a capital K) on every call. It can go in any of these places:

• In the URL: ?apiKey=YOUR_API_KEY. Simple, and the usual choice for GET requests.
• In the form fields of a POST.
• In a JSON body: {"apiKey": "YOUR_API_KEY", ...}.

For POST requests, prefer the body over the URL. URLs tend to end up in server logs and browser history. Never put your key in JavaScript that runs in a visitor's browser. Call the API from your server.

Sending Data

When you create or update a record, send the fields in one of two ways.

As form fields, the same way an HTML form posts:

curl -X POST "https://rental.software/api6/customers" \
  -d "apiKey=YOUR_API_KEY" \
  -d "name=Jordan Rivera" \
  -d "email=jordan.rivera@example.com"

Or as JSON, with the Content-Type: application/json header:

curl -X POST "https://rental.software/api6/customers" \
  -H "Content-Type: application/json" \
  -d '{"apiKey": "YOUR_API_KEY", "name": "Jordan Rivera", "email": "jordan.rivera@example.com"}'

HTML tags are removed from the values you send.

How Responses Work

Status Codes

Always check the HTTP status code first. A code in the 200s means the call worked. A code in the 400s means something was wrong with the request, and the JSON body has a message explaining what. The full list is in API - Errors and Rate Limits.

Creating and Updating

When you create or update a customer or a lead, the answer tells you the ID of the record in recordid:

{
  "status": 201,
  "message": "Created",
  "recordid": 533297,
  "request_time": 1760000000
}

Keep that ID. You need it to read, update or link the record later.

Lists and Paging

List endpoints return a page of records at a time, in items. Two parameters control the page:

• limit is how many records you want. The default is 25.
• offset is how many records to skip. The default is 0.

To read a whole list, start at offset=0 and add your limit each time (0, 100, 200 and so on). Stop when a page comes back with fewer records than your limit. If you ask for a page past the end, most lists answer with HTTP 404.

The first, next and previous links in a response show the offsets for you, but they do not include your API key or your other parameters. Add those again before calling one.

More Detail With _body

Many list calls return a short version of each record to stay fast. Add _body=true to get the full records. The request takes longer, so use it only when you need the extra fields.

Dates and Times

Most date fields come back three ways, so you can use whichever is easiest:

"createtime": "2025-09-29T16:47:54-04:00",
"createtime_ts": "1759178874",
"createtime_utc": "2025-09-29T20:47:54Z"

• The plain field is the date and time in your account's time zone.
• _ts is a Unix timestamp: the number of seconds since January 1, 1970 (UTC).
• _utc is the same moment in UTC.

When you send a date, each endpoint article says which format it expects. Most accept a Unix timestamp.

Extra Fields

Responses often include more fields than the articles list, and new fields can be added over time. Write your code so it reads the fields it needs and ignores the rest.

Rate Limits in Short

An API key can make 15 calls in 10 seconds and 300 calls in 5 minutes. Past that, calls are refused with HTTP 429 for a short time. Details and sample code are in API - Errors and Rate Limits.

Endpoint Index

Getting Started

• API - Setup Access: create a key and grant permissions
• API - Errors and Rate Limits: status codes, messages and limits
• API - Transaction Charges: what calls cost and how to see your usage
• API - Packages and Endpoint Access: which subscription package each endpoint needs
• API - PHP Example: a complete working call in PHP
• API - Migration (API1-5 to API6): moving an old integration to API6

Customers and Leads

Inventory, Availability and Pricing

Settings Lists

Workers

Sales CRM

Vendors

Messaging, Webhooks and Zapier

A Typical First Project

A common first integration is a custom quote form on your own website. The calls it makes are:

1. GET /api6/categories_list and GET /api6/rentals to show what you offer. Store the results and refresh them once a day.
2. POST /api6/availability_pricing to check that the items are free on the customer's date and to show a price.
3. POST /api6/leads with the customer's details, the event details and the chosen items. This creates the customer and the lead in one call.

The PHP example shows how to make these calls from code.