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

# Knot API Documentation

> Connect your app to your users' merchant accounts. Guides, SDKs, and API reference for CardSwitcher, TransactionLink, SubscriptionManager, and more.

export const openAssistant = q => {
  window.location.assign(`/?assistant=${encodeURIComponent(q)}`);
};

Knot connects apps to their users' online merchant accounts (Amazon, Netflix, Uber, DoorDash, and so on) so the app can read data from and write data to those accounts.

## How Knot works

Every product follows the same four steps:

1. The backend creates a session with [Create Session](/api-reference/sessions/create-session) (`POST /session/create`), using Basic auth with the `client_id` and `secret` and the `Knot-Version` header. Create a new session each time the SDK opens.
2. The client app opens the [SDK](/sdk/introduction) with that session, and the user logs in to a merchant.
3. The backend receives [webhooks](/webhooks). Webhooks are the source of truth; SDK callbacks are for UI only.
4. The backend calls the product's API.

Base URLs: `https://development.knotapi.com` (development) and `https://production.knotapi.com` (production). API keys come from Knot; see [Authentication](/api-reference/authentication).

## Products

* [CardSwitcher](/card-switcher/quickstart): update a user's payment card on file at merchants.
* [Vaulting](/vaulting/quickstart): set a digital wallet as the default payment method at merchants.
* [SubscriptionManager](/subscription-manager/quickstart): retrieve subscriptions and bills, and cancel subscriptions server-side.
* [TransactionLink](/transaction-link/quickstart): retrieve SKU-level transaction data from merchant accounts.
* [Detect](/detect/quickstart): identify which merchant accounts a user has.
* [Shopping](/shopping/quickstart): create carts and check out at merchants.

## SDKs

[iOS](/sdk/ios), [Android](/sdk/android), [React Native](/sdk/react-native), [Flutter](/sdk/flutter), and [Web](/sdk/web). Knot has no server-side SDK; the backend calls the API directly over HTTPS.

## Developer resources

* [API reference](/api-reference/authentication) and [OpenAPI specification](/api-reference/openapi.json)
* [Webhooks](/webhooks)
* [Launch checklist](/launch-checklist)
* [Skills](/ai/skills): install with `npx skills add https://docs.knotapi.com`
* [MCP server](/ai/mcp-server): install with `npx add-mcp https://docs.knotapi.com/mcp --name knot-docs`
* [Knot Dashboard](https://dashboard.knotapi.com)
* [Contact Knot](https://www.knotapi.com/contact/)


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.