# Send SMS, email and push with one call

> One endpoint, three channels: set channel and Relay handles formatting, retries and fallbacks.

Source: https://helpdox.fekbd.com/docs/relay-api/messages/send-sms-email-and-push-with-one-call/

One endpoint, three channels: set `channel` and Relay handles formatting, retries and fallbacks. Follow the steps below — it takes just a few minutes.

## Before you begin

- A Relay account and a test-mode API key
- `curl` or one of the official SDKs

## Steps

1. 1Choose a channel`sms`, `email` or `push`.
2. 2Add a fallbackSet `fallback: "email"` to email the user if SMS fails.
3. 3Track deliveryEach attempt appears in `events` on the message.

Tip

Use idempotency keys so a retried request never sends twice.

POST`/v3/messages`

## Create a message

Queues a message on one channel, with an optional fallback channel.

Requires `messages:write`

Parameters

- **channelstringrequired**: `sms`, `email` or `push`.
- **tostringrequired**: Phone number in E.164 format, email address or device token.
- **bodystringrequired**: Message text. SMS longer than 160 characters is split.
- **fallbackstring**: Channel to try if the first one fails.
- **send_atdatetime**: Schedule for later (ISO 8601).

POST /v3/messages

```
curl https://api.relay.example/v3/messages \
  -H "Authorization: Bearer $RELAY_KEY" \
  -H "Idempotency-Key: order-1042-receipt" \
  -d channel=sms -d fallback=email \
  -d to=+15550100001 -d body="Order #1042 shipped"
```

Response

202 Accepted

```
{
  "id": "msg_7Hq2kD",
  "channel": "sms",
  "status": "queued",
  "fallback": "email",
  "created_at": "2026-10-12T16:04:11Z"
}
```

## Still stuck?

Include the request ID from the `Relay-Request-Id` response header — it lets us find your call in seconds.