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

# Building Blocks

> Task-specific DualEntry Public API guidance: syncing attachments, pushing an inbound bank feed, and calculating tax before creating an invoice or bill.

These guides cover specific integration tasks that come up often enough to document on their own, each independent of the others.

## What this section covers

* **[Working with Attachments](./working-with-attachments)**: attach files to a record and the limits that apply.
* **[Bank Connections: Inbound Feed API](./bank-connections-inbound)**: push bank transactions into DualEntry from your own systems.
* **[Calculate Tax, Then Create an Invoice or Bill](./calculate-tax-before-invoicing)**: get a tax calculation and apply it before you post the record.

## Where to go next

For the mechanics that apply across all of these (pagination, errors, idempotent writes), see [Core Concepts](/developers/guides/api/core-concepts/index). For a full custom integration, see [How Custom Integrations Work](/developers/guides/integrations-and-tools/how-custom-integrations-work).