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

# Legacy API Overview

> Long-term support documentation for the Phonovation legacy APIs.

<Warning>
  These APIs are maintained for **long-term support** only. New integrations should use the [Phonovation SMS API v2](/api-reference/introduction), which offers OAuth 2.0 authentication, campaign naming, scheduling, and improved error handling.
</Warning>

The v1 APIs are available at `https://secure.interactsms.com/api/v1` and use **basic credential authentication** (username and password passed directly in the request body).

## Available legacy APIs

<CardGroup cols={2}>
  <Card title="JSON API (v1)" icon="brackets-curly">
    Send SMS via a JSON request body. Credentials passed as `User` and `Password` fields.
  </Card>

  <Card title="URL-Encoded API (v1)" icon="link">
    Send SMS via `application/x-www-form-urlencoded`. Compatible with query-string integrations.
  </Card>
</CardGroup>

## Key differences vs v2

| Feature           | v1 (Legacy)                | v2 (Current)                |
| ----------------- | -------------------------- | --------------------------- |
| Auth              | Credentials in body        | OAuth 2.0 JWT               |
| Bulk send         | Single recipient           | Multiple recipients         |
| Scheduling        | Unix timestamp             | ISO 8601 datetime           |
| Campaign tracking | `NotifyId` only            | `campaignName` + `notifyId` |
| Response format   | Plain text / status string | Structured JSON             |