> For the complete documentation index, see [llms.txt](https://developer.ecall-messaging.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.ecall-messaging.com/api-references/https-interface.md).

# HTTPS Interface

Send SMS, fax, and voice messages through the eCall HTTP(S) interface, query delivery status, and receive callbacks.

Use the eCall HTTP(S) interface to send messages by calling URL endpoints directly.

### At a glance

* Base URL: `https://url.ecall.ch/`
* Request style: URL parameters with **GET** or **POST**
* Supports: SMS, fax, voice, status queries, callbacks, and inbound SMS forwarding

{% hint style="info" %}
Parameter names are case-insensitive. Send all content as UTF-8.
{% endhint %}

### Core features

* Send SMS, fax, and voice messages.
* Query delivery status with `Api/State`.
* Receive replies, notifications, and inbound SMS events.

### In this section

* [Getting started](/api-references/https-interface/getting-started.md) — prerequisites, request format, endpoint details, and browser testing
* [Send methods](/api-references/https-interface/send-methods.md) — SMS, fax, and voice endpoints, parameters, and examples
* [Status queries](/api-references/https-interface/status-queries.md) — query message status and interpret response codes
* [Message cache](/api-references/https-interface/message-cache.md) — read and delete cached inbound SMS messages
* [Callbacks and inbound SMS](/api-references/https-interface/callbacks-and-inbound-sms.md) — replies, delivery notifications, and inbound forwarding
* [Response codes and headers](/api-references/https-interface/response-codes-and-headers.md) — HTTP statuses, eCall result codes, request IDs, and source IPs