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

# How to Send an SMS Message in Postman

> Send your first SMS with the Hypersender API from Postman: add your API token, build the request, and send a message from your own SIM card.

Send your first SMS with the Hypersender SMS API in Postman. The interactive demo below walks through configuring the request; the written steps mirror it so you can build the same call in your own code.

Messages are sent by the Android phone linked to your instance, so the recipient sees your own SIM card number.

[Seamlessly Configure and Test API Requests with Hypersender SMS](https://demo.arcade.software/4eIF73n5oj3HBhoII0yh?embed\&embed_mobile=tab\&embed_desktop=inline\&show_copy_link=true)

## What you need

* A [Hypersender account](https://app.hypersender.com/register) with an active instance.
* Your **API token** and **instance UUID** from the dashboard.
* The Hypersender Android app installed, linked, and online — see the [SMS quick start](https://docs.hypersender.com/v2/hypersender/overview/sms/sms-quick-start.md).
* [Postman](https://www.postman.com/downloads/) installed, or the [SMS Postman collection](https://docs.hypersender.com/v2/api-reference/sms/sms-collection.json) imported.
* The recipient phone number in international format, for example `+1119122018`.

## Request

**`POST`** `https://app.hypersender.com/api/sms/v1/{instance}/send-message`

```http theme={null}
Authorization: Bearer YOUR_API_TOKEN
Content-Type: application/json
```

```json theme={null}
{
  "to": "+1119122018",
  "content": "Your verification code is 439713",
  "request_id": "133554b5-ae44-44a0-8f4f-7bbac5657a11"
}
```

`request_id` is your own idempotency key, so retrying the same request never sends the message twice. You can also pass `schedule_send_at` to queue the message for a later time, `max_send_attempts`, and `message_expiration_seconds`.

## What the phone does

1. The API hands the message to the linked Android phone.
2. The phone sends it through your SIM card and reports back the status.
3. Delivery updates arrive on your configured webhook — see [SMS webhooks](https://docs.hypersender.com/v2/api-reference/sms-webhooks/sms-webhooks-introduction.md).

> [!WARNING]
>
> The message arrives from your phone number, not a custom sender name. Custom sender names require carrier and regulatory approval that Hypersender does not currently offer.

## Troubleshooting

> [accordion] 401 Unauthorized
>
> The `Authorization` header is missing or the token was rotated. Generate a new token in the dashboard and update the header.

> [accordion] Message stays pending
>
> The API confirms the request before the phone sends it. Check the heartbeat status of your device — if there has been no heartbeat for more than two hours, Hypersender marks it offline.

> [accordion] Delivery fails repeatedly
>
> Verify the number is in international format and that the SIM card has credit for the destination country. International messages are billed by your carrier.

## Next steps

> [card] [Send Message reference](https://docs.hypersender.com/v2/api-reference/sms/messages/send-message.md)
>
> Every parameter for the SMS send endpoint.

> [card] [Heartbeats](https://docs.hypersender.com/v2/api-reference/sms/heartbeats/sms-heartbeats-api.md)
>
> Monitor whether your phone is online and ready to send.

> [card] [Create your Hypersender account](https://app.hypersender.com/register)
>
> Get your API token, link the Android app, and send your first SMS.


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