Yeastar SMS: add two-way business texting to Yeastar P-Series with everymessage

How the integration works

When an agent sends a text, Yeastar posts it to everymessage with your API key, and we send it to the mobile networks. When a customer replies to your number, we sign the reply with your Secret and post it to your Yeastar PBX, which routes it to the extension, message queue or message flow you choose. Yeastar can also check the connection from time to time with a quick verification request.

What you need

• Yeastar P-Series Software Edition, firmware 83.23.0.24 or later
• A domain name for your PBX with a valid certificate. Yeastar notes the domain must not contain an underscore
• An everymessage account with an API key, and a Secret for signing webhooks
• An SMS-enabled number from everymessage for customers to text and reply to

Setting it up in Yeastar

1. Get your details from us. We provide your API key (your API username:password, Base64-encoded), a Secret, and your SMS number.
2. Add the channel. In the Yeastar web portal go to Messaging > Message Channel, click Add and choose SMS.
3. Fill in the Authentication tab. Enter a name, set ITSP to General, and enter the values in the table below.
4. Send us the webhook URL. Choose a Webhook URL from the drop-down, copy it and send it to us. We set it against your number with your Secret, so replies are signed.
5. Set the sending rate. On the Messaging Settings tab, set the message sending rate. Ask us if you need to send faster than your account allows.
6. Add your number. In the Number section, add your everymessage number in E.164 format, for example +447700900456, and choose where inbound messages go: an extension, a message queue or a message flow. Then choose which extensions can start conversations, and save.
7. Test. Check the channel shows as connected, send a text from Linkus, then reply from the mobile and check the reply reaches the right agent.

API reference

You don’t need this to use Yeastar, but it shows exactly what Yeastar and everymessage exchange, which helps when testing or troubleshooting. The full reference, with code examples, is in our developer docs: Phone systems (PBX) API.

Verify the connection

Yeastar sends a random challenge with your API key. A valid key returns HTTP 200 with the same challenge in the body.

curl "https://api.everymessage.com/v1/pbx/verify?challenge=mAWpGnyeTZgguOPY" \
  -H "Authorization: Bearer YOUR_API_KEY"

Send a message

Yeastar posts each text as JSON. from, to and text are all required, and numbers are in E.164 format.

curl -X POST "https://api.everymessage.com/v1/pbx/messages" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{"from": "+447700900456", "to": "+447700900123", "text": "Your order is ready to collect."}'

A successful request returns HTTP 200 with the message details, including the everymessage message id. Errors return a JSON errors list using Yeastar’s error codes, listed under common problems below.

Replies

Customer replies are posted to your Yeastar webhook as a message.received event. When a Secret is set, the request carries an X-Signature-256 header: sha256= followed by the lowercase hex signature of the request body made with your Secret.

{
  "data": {
    "event_type": "message.received",
    "record_type": "event",
    "payload": {
      "id": "123789",
      "direction": "inbound",
      "type": "SMS",
      "from": { "phone_number": "+447700900123" },
      "to": [ { "phone_number": "+447700900456" } ],
      "text": "Can I collect it tomorrow?",
      "received_at": "2026-10-13T09:15:04.511Z"
    }
  }
}

Common problems and fixes

Why use everymessage for Yeastar SMS

Using 3CX? The same everymessage PBX API works with it too: see 3CX SMS. For other platforms, see NetSapiens SMS, Amazon Connect and every way to connect on our Business SMS page.

Frequently asked questions