> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://trustly.ferndocs.com/integrate/core-concepts/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://trustly.ferndocs.com/_mcp/server.

# Core concepts

Before building your integration, familiarize yourself with Trustly's core building blocks — from the Establish Data object that configures every transaction to the webhook events that drive your backend logic.

#### [Key concepts](/integrate/core-concepts/key-concepts)

The A2A payment model, Trustly Lightbox, and transaction lifecycle.

#### [The Establish Data object](/integrate/core-concepts/the-establish-data-object)

Configure merchant credentials, transaction details, and customer data.

#### [Transactions and transaction IDs](/integrate/core-concepts/transactions-and-transaction-ids)

How transaction IDs track authorizations and payment events.

#### [Tokens and account security](/integrate/core-concepts/tokens-and-account-security)

Tokenized bank account information and stored credential security.

#### [Redirect URLs and return flow](/integrate/core-concepts/redirect-urls-and-return-flow)

Configure return and cancel URLs for user redirects.

#### [Webhooks and events](/integrate/core-concepts/webhooks-and-events)

Receive asynchronous transaction status updates.

#### [Content strings](/integrate/core-concepts/content-strings)

Trustly-provided UI strings for product names and messaging.

> Foundational components, data models, and security patterns that power Trustly integrations.

## Docs

- [Key concepts](https://trustly.ferndocs.com/integrate/core-concepts/key-concepts.md)
- [Establish Data object](https://trustly.ferndocs.com/integrate/core-concepts/the-establish-data-object.md)
- [Transaction ID](https://trustly.ferndocs.com/integrate/core-concepts/transactions-and-transaction-ids.md)
- [Tokens and Account Security](https://trustly.ferndocs.com/integrate/core-concepts/tokens-and-account-security.md)
- [Redirect URLs](https://trustly.ferndocs.com/integrate/core-concepts/redirect-urls-and-return-flow.md)
- [Webhooks and Events](https://trustly.ferndocs.com/integrate/core-concepts/webhooks-and-events.md): Learn about Trustly event notifications (webhooks) and client-side event listeners
- [Content Strings](https://trustly.ferndocs.com/integrate/core-concepts/content-strings.md)