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API Integration GuideWebhook Synchronization

Integrate customer support messaging with your helpdesk

Support messaging integration has two directions, and the second is where most setups fall short: sending the ticket update is easy; getting the customer's reply back into the same ticket is what keeps agents out of copy-paste purgatory.

SendiMessage closes the loop with two primitives: the status_callback URL (embed the ticket id in it for delivery events) and receive webhooks carrying the customer's number, which your handler matches to the open ticket and appends through the helpdesk's API. Zendesk, Intercom, Freshdesk, and Gorgias guides show each platform's trigger mechanism — the reply loop is identical everywhere.

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What this integration enables

Status updates
Ticket transitions notify the customer without an email they won't open.
Agent replies by text
Public comments can go out as messages for phone-first customers.
Replies into tickets
receive events append to the ticket via your handler.
CSAT follow-up
A closed ticket triggers one respectful satisfaction question.
Escalation alerts
Priority changes notify the customer — and optionally your on-call staff.

Architecture

How it fits together: Helpdesk event, then Automation or middleware, then SendiMessage API, then Customer, then Reply webhook, then Ticket update.
  1. Helpdesk eventTicket updated, agent replied, ticket closed
  2. Automation or middlewareBuilds the message, embedding the ticket id in the status_callback URL
  3. SendiMessage APIPOST /send-message
  4. CustomerUpdate arrives; reply invited
  5. Reply webhookreceive event with the customer's number
  6. Ticket updateYour handler appends the reply as a comment

Example request

cURL
curl -sS https://api.sendimessage.com/v1/send-message \
  -H "X-API-Key: $SENDIMESSAGE_API_KEY" \
  -H "X-API-Secret: $SENDIMESSAGE_API_SECRET" \
  -H "Content-Type: application/json" \
  -d '{
    "number": "+15555550123",
    "content": "Your appointment is tomorrow at 10:00 AM."
  }'
# → {
#   "status": "QUEUED",
#   "message_handle": "4e828182-a640-483f-bfe9-17ffcaa51d48",
#   "to": "+14155550123",
#   "service": null,
#   "is_outbound": true,
#   "error_message": null,
#   "date_sent": null
# }

Delivery events and incoming replies

One webhook endpoint serves every helpdesk: verify the signature, match the sender's number to the open ticket, and append the reply through the helpdesk API.

webhook event
// "outbound" event → your your_helpdesk endpoint
// Verify the SendiMessage-Signature header (t={timestamp},v1=HMAC-SHA256 of
// "{timestamp}.{raw body}", keyed with your webhook secret), then use
// GET /v2/messages/{message_handle} for authoritative state and match it to
// your ticket_id in your_helpdesk.

Limitations and honest notes

  • iMessage delivery is available on supported messaging lines and destinations. Recipients without iMessage receive SMS when fallback is configured — never assume universal iMessage availability.
  • Messages are accepted asynchronously — the API returns status QUEUED and final status arrives via webhook or the message endpoints.
  • No official SDK for this ecosystem yet — the example uses plain HTTP against the REST API. Official SDKs are published for JavaScript/TypeScript (npm: sendimessage), Python (PyPI: sendimessage), PHP (Composer: sendimessage/sdk), and Go (github.com/sendimessage/sendimessage-go). Every SDK is dependency-free and covers the full public API surface.
  • Ticket write-backs are performed by your handler or automation platform — automatic helpdesk synchronization is not claimed.

Frequently asked questions

Which helpdesks have dedicated guides?
Zendesk, Intercom, Freshdesk, and Gorgias today. Any helpdesk with workflow webhooks and an API for adding comments supports the same loop.
Can urgent replies page a human?
Yes — your webhook handler sees every reply first, so keyword or sentiment rules can notify on-call staff before (or instead of) appending quietly to the ticket.

Ready to connect Customer Support Messaging?

Request a messaging line and a SendiMessage integration specialist will review your Customer Support Messaging workflow and guide the setup.