---
title: Plans, add-ons and charges
description: The three kinds of catalog item, how groups organize them, and which add-ons go with which plans.
domain: product
status: shipped
visibility: public
last_verified: 2026-08-28
order: 10
---
Everything you sell lives in the catalog, and every catalog item is one of three kinds. The kind decides how the item behaves when you bill it.

## The three kinds

| Kind | What it is |
|---|---|
| Plan | The recurring base of a subscription. A subscription is built on a plan. |
| Add-on | A recurring extra attached alongside a plan, like an extra feature or seat pack. |
| Charge | A one-time item, like a setup fee or an implementation service. Billed once, on an invoice. It never repeats. |

A subscription is anchored by a plan, with add-ons riding alongside it. A charge is billed once: put it on a subscription, at signup or later, and it is queued in full as a pending charge and billed on that subscription's next invoice, never prorated and never repeated. Until it bills, you can void it from the subscription's unbilled charges. A charge can also go straight onto a one-off invoice.

## Groups

A group organizes the catalog into product lines: say a *CRM* group and a *Helpdesk* group, each holding its own Starter, Pro and Enterprise plans. Groups are purely visual. They section the catalog list and pickers, and they never limit what a subscription can contain or which plan a customer can change to. If you're coming from a system with "product families", note the difference: a group won't block a plan change the way a family wall does.

```viz subscription-anatomy
```

The page on [how the catalog becomes a subscription](/guide/product-catalog/building-a-subscription) walks through how these fit together and what a customer is charged at signup.

## Which add-ons go with which plans

Every add-on has an **availability** setting, managed on the add-on's own page. It has two modes:

- **Available on all plans.** The default. Any subscription can add it, and new plans include it automatically.
- **Only on selected plans.** The add-on lists the plans that accept it, and subscriptions on other plans won't see it.

Selecting the first plan is what switches an add-on from the first mode to the second, and the app says so before it happens. Each plan's page mirrors the same setting: it shows every add-on a subscription on that plan can carry, including the all-plans ones. From there you can also add an already-limited add-on to the plan; limiting an all-plans add-on for the first time happens on the add-on's own page, since that changes where it is offered everywhere.

This keeps your catalog coherent: a seat pack meant for the Team plan will not accidentally end up on a Starter subscription.

## In the API

Catalog items are created through the `POST /v1/products` endpoint. The API calls them products, and the kind values are `plan`, `addon`, and `one_off` (shown in the app as Plan, Add-on, and Charge). A group is the `category` field. Prices are created separately; see [prices](/guide/product-catalog/prices) and the [API reference](/reference).

## Edge cases

- **A subscription needs a plan.** Add-ons and charges attach to a subscription, but the plan is what a subscription is built on.
- **Charges are not metered.** A one-time charge is a fixed thing you bill once, not something measured over a period.
- **Compatibility is an allow-list.** It says which add-ons may go on a plan. It does not force any add-on onto a subscription.