Sending SMS to eSIMs

The eSIM Go API lets you send SMS messages directly to an eSIM by ICCID. This is useful for sending automated messages to your end users — for example, a welcome message when their eSIM first connects to a network.

Endpoint

POST /v2.5/esims/{iccid}/sms

Request

curl -X POST https://api.esim-go.com/v2.5/esims/{iccid}/sms \
  -H 'X-API-Key: $API_KEY' \
  -H 'Content-Type: application/json' \
  -d '{
    "message": "Welcome! Your eSIM is now active.",
    "from": "eSIM"
  }'

Field	Required	Description
`message`	Yes	The message to send. UTF-8, 1–160 characters.
`from`	No	Sender name shown on the recipient’s device. Defaults to `eSIM`.

A successful response returns 200:

{
  "status": "sent"
}

Custom sender names

The from field defaults to eSIM and is the only supported value by default. If you need a custom sender name — for example your brand name — contact your account manager to have one assigned to your organisation.

Constraints

Messages must be UTF-8 compliant and between 1–160 characters
SMS cannot be sent to a deactivated eSIM — this returns 400 Bad Request
The ICCID must belong to your organisation

Pairing with webhooks

A common pattern is to send a welcome SMS when an eSIM first connects to a network. Set up a First Attachment webhook and trigger an SMS in response:

eSIM Go sends a FirstAttachment callback to your endpoint
Your server calls POST /v2.5/esims/{iccid}/sms with a welcome message
The end user receives an SMS confirming their eSIM is active

This removes the need for you to track when an eSIM is first used — the platform tells you.