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

# Reference

> Technical reference for Mercur's HTTP APIs, panel extensions, and configuration.

This section is the technical contract of the Mercur core plugin. The
[Learn](/learn/introduction) tab explains concepts and the
[Platform](/platform/store/overview) tab documents each domain's data models,
workflows, service, and events. These pages cover the HTTP APIs, the panel
extension helpers, and configuration.

## HTTP API

Mercur extends the Medusa server with three route surfaces. Start with the
conventions page: authentication, seller scoping, and pagination work the same
way across all of them.

<CardGroup cols={2}>
  <Card title="API conventions" href="/references/api/conventions">
    Authentication, seller scoping, pagination, field selection, and webhooks.
  </Card>

  <Card title="Admin API" href="/references/api/admin">
    Operator routes under <code>/admin/\*</code>.
  </Card>

  <Card title="Vendor API" href="/references/api/vendor">
    Seller-scoped routes under <code>/vendor/\*</code>.
  </Card>

  <Card title="Store API" href="/references/api/store">
    Storefront routes under <code>/store/\*</code>.
  </Card>
</CardGroup>

## Panel extensions

File-based helpers for extending the Admin and Vendor panels without forking.

<CardGroup cols={2}>
  <Card title="Overview" href="/references/panel-extensions/overview">
    Typed targets, persistence, and how the helpers fit together.
  </Card>

  <Card title="Widgets" href="/references/panel-extensions/widgets">
    <code>defineWidgetConfig</code>: zones, config, and component props.
  </Card>

  <Card title="Custom Fields" href="/references/panel-extensions/custom-fields">
    <code>defineCustomFieldsConfig</code>: forms, displays, and list columns.
  </Card>

  <Card title="Create a new page" href="/references/panel-extensions/create-page">
    <code>defineNavigationConfig</code> and <code>createFormHelper</code>.
  </Card>
</CardGroup>

## Configuration

<CardGroup cols={2}>
  <Card title="Configuration" href="/references/configuration">
    <code>withMercur()</code>, environment variables, and provider options.
  </Card>

  <Card title="Platform modules" href="/platform/store/overview">
    Data models, workflows, service, and events for each domain.
  </Card>
</CardGroup>