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

# API documentation

> Build on Commenda's APIs to manage entities, calculate indirect tax, automate workflows, and more.

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Commenda exposes several APIs that let you programmatically manage business entities, calculate indirect tax, incorporate companies, build workflows, and more. This page helps you find the right API for your use case and get started quickly.

## Available APIs

<Columns cols={2}>
  <Card title="Global Indirect Tax" icon="receipt" href="/engine/indirect-tax/introduction">
    Calculate tax rates, manage registrations, track transactions, handle exemptions, and automate filings across jurisdictions.
  </Card>

  <Card title="CommendaOS" icon="microchip" href="/engine/commendaos/overview">
    Create and manage business entities, government identifiers, registrations, locations, credentials, and documents.
  </Card>

  <Card title="Company Name Checker" icon="magnifying-glass" href="/engine/company-name-checker/introduction">
    Check company name availability across US state jurisdictions before incorporation.
  </Card>

  <Card title="Compliance Calendar Preview" icon="calendar-check" href="/engine/compliance-calendar/overview">
    Generate a stateless preview of compliance obligations for a corporation profile and target fiscal year.
  </Card>

  <Card title="Incorporation" icon="building" href="/engine/incorporation/introduction">
    Create companies, start incorporation services, and track payment intents and document delivery through affiliate-scoped endpoints.
  </Card>

  <Card title="Workflow Builder" icon="diagram-project" href="/engine/workflow-builder/overview">
    Define multi-step service request workflows with conditional logic, approvals, and automated task assignment.
  </Card>

  <Card title="Address API" icon="location-dot" href="/engine/address-api/introduction">
    Geocode and validate addresses for accurate tax jurisdiction resolution.
  </Card>
</Columns>

## Which API do you need?

| Use case                                                 | API                                                                                     |
| -------------------------------------------------------- | --------------------------------------------------------------------------------------- |
| Calculate indirect tax on a transaction                  | [Global Indirect Tax](/engine/indirect-tax/introduction)                                |
| Create or retrieve business entities                     | [CommendaOS](/engine/commendaos/overview)                                               |
| Check company name availability before incorporation     | [Company Name Checker](/engine/company-name-checker/introduction)                       |
| Preview compliance obligations for a corporation profile | [Compliance Calendar Preview](/engine/compliance-calendar/overview)                     |
| Incorporate a new entity programmatically                | [Incorporation](/engine/incorporation/introduction)                                     |
| Manage tax registrations across jurisdictions            | [Global Indirect Tax — Registrations](/engine/indirect-tax/registrations/registrations) |
| Track registration thresholds                            | [Global Indirect Tax — Registration Thresholds](/engine/indirect-tax/nexus/nexus-GET)   |
| Store and retrieve entity documents                      | [CommendaOS — Documents](/engine/commendaos/documents)                                  |
| Automate multi-step service delivery                     | [Workflow Builder](/engine/workflow-builder/overview)                                   |
| Validate or geocode an address                           | [Address API](/engine/address-api/introduction)                                         |

## Authentication

Commenda APIs use two authentication methods depending on the API:

### Legacy Affiliate API

The legacy affiliate API uses an affiliate API key passed in the `x-api-key` header:

```bash theme={null}
curl --request GET \
  --url 'https://api.prod.commenda.io/api/v1/public/payment-intents' \
  --header 'x-api-key: <your_api_key>'
```

### CommendaOS Partner API

The CommendaOS Partner API uses a partner API key passed in the `x-api-key` header:

```bash theme={null}
curl --request GET \
  --url 'https://api.prod.commenda.io/api/v1/partner/commenda-os/customers/77/business-entities' \
  --header 'x-api-key: <partner_api_key>'
```

### Managing partner API keys

Manage partner API keys in the Commenda dashboard under **Settings > API keys**. New keys are prefixed with `cmda_` and are shown only once when they are created. Copy the key immediately and store it securely, because Commenda stores only a SHA-256 hash of the key and cannot show the raw value again later.

To rotate a key, create a new key in the dashboard, update your integration to use it, confirm requests succeed, and then delete the old key.

### Global Indirect Tax API

The Global Indirect Tax API uses Bearer token authentication. Include your token in the `Authorization` header of every request:

```bash theme={null}
curl --request GET \
  --url 'https://transaction-tax.api.in.commenda.io/api/v1/registrations' \
  --header 'Authorization: Bearer <your_token>'
```

<Info>
  If **Settings > API keys** is not available in your dashboard, contact the Commenda team to enable API key management for your account.
</Info>

## Base URLs

| API                       | Base URL                                                    |
| ------------------------- | ----------------------------------------------------------- |
| Global Indirect Tax       | `https://transaction-tax.api.in.commenda.io/api/v1`         |
| Partner Incorporation API | `https://api.prod.commenda.io/api/v1/partner/incorporation` |
| CommendaOS Partner API    | `https://api.prod.commenda.io/api/v1/partner/commenda-os`   |
| Legacy Affiliate API      | `https://api.prod.commenda.io/api/v1/public`                |

All endpoint paths in this documentation are relative to their respective base URL.

## Next steps

<Columns cols={2}>
  <Card title="Global Indirect Tax quickstart" icon="bolt" href="/engine/indirect-tax/introduction">
    Start calculating tax rates and managing transactions.
  </Card>

  <Card title="CommendaOS overview" icon="database" href="/engine/commendaos/overview">
    Learn the entity data model before calling the API.
  </Card>
</Columns>