# cartflows/3.3.0/modules/optin/architecture.md

CartFlows – Funnel Builder & Checkout Plugin for WooCommerce, version 3.3.0. 18 lines.

- Page: https://pluginprobe.com/plugins/cartflows/3.3.0/code/modules/optin/architecture.md
- Raw: https://pluginprobe.com/plugins/cartflows/3.3.0/raw/modules/optin/architecture.md
- Modified: 2026-10-05T04:31:02+00:00

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```markdown
---
module: optin
---

# optin

## Responsibility

Owns the CartFlows Optin step: it renders a stripped-down WooCommerce checkout (name + email only, no payment) through the `[cartflows_optin]` shortcode, preconfigures the cart with a single free virtual product, generates and caches the step's dynamic CSS, and defines the optin step's admin meta and design settings schema.

Ownership stops at the WooCommerce checkout pipeline itself — it never renders form fields, validates, or creates the order. It bends Woo's hooks and then hands off to `[woocommerce_checkout]`. Loaded only when WooCommerce is active.

## Why it is this way

An optin step is a checkout with almost everything removed, and WooCommerce offers no supported way to render a partial checkout. The module therefore forces `woocommerce_is_checkout` true, empties the gateway list, and clears six hook stacks with `remove_all_actions()` at a `wp` priority high enough to run after everyone else has registered.

That approach is why so many of the constraints here are about *timing* rather than API: the priority-1000 teardown and the priority-1 cart configuration are a pair, and the two `is_wc_endpoint_url( 'edit-address' )` bail-outs exist purely because the billing filters registered here are global and would otherwise reshape an unrelated My Account page.

```