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API Integration GuideWorkflow + HTTP Request

Send SMS and supported iMessage messages from HubSpot workflows

HubSpot combines CRM, marketing, sales, and service hubs, with Workflows as the automation engine most teams live in — contact-based, deal-based, and ticket-based triggers with branching logic.

SendiMessage plugs into those Workflows two ways: a webhook action that posts directly to the SendiMessage API (Operations Hub), or a custom code action that builds the payload in Node.js or Python with the key stored as a secret. Contact properties fill the message; store the returned message_handle (or embed the contact id in the status_callback URL) so delivery events and replies can be written back to the timeline through the HubSpot API.

Connect SendiMessage to HubSpot using the SendiMessage REST API, CRM workflow automation, server-side functions, or webhooks. There is no native HubSpot marketplace application today — the methods below are what actually works, labeled honestly.

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What this integration enables

Lead follow-up
Message a new lead shortly after capture, while interest is warm and consent is fresh.
Appointment reminders
Remind contacts before meetings and bookings created in the CRM.
Sales notifications
Confirm quotes, proposals, and next steps as deals progress.
Customer support updates
Keep customers informed as cases and tickets move forward.
Renewal and payment reminders
Nudge customers ahead of renewals or due invoices.
Two-way conversations
Incoming replies return through webhooks and can be written back to the record timeline.

Implementation options

HubSpot Workflows (webhook or custom code actions) + HTTP request
Use HubSpot Workflows (webhook or custom code actions) to call POST /send-message directly when a record changes. Fastest path when your plan supports outbound HTTP calls.
Middleware integration
A small backend service sits between HubSpot and SendiMessage: it receives CRM events, applies your consent and formatting rules, sends the message, and writes delivery events back to the record.
Automation platform
Zapier, Make, n8n, or Power Automate can bridge HubSpot triggers to SendiMessage HTTP actions without custom code.
Webhook-based synchronization
SendiMessage posts outbound and receive events to your endpoint; correlate them with the stored message_handle (or ids embedded in your status_callback URL) to update the HubSpot timeline.

Architecture

How it fits together: HubSpot event, then Workflow or backend, then SendiMessage API, then Managed messaging line, then SMS or supported iMessage, then Customer, then Delivery or reply event, then Signed webhook, then HubSpot timeline update.
  1. HubSpot eventA record changes, a stage moves, or a workflow fires
  2. Workflow or backendHubSpot automation or your middleware prepares the request
  3. SendiMessage APIPOST /send-message — the message is validated and queued
  4. Managed messaging lineYour dedicated line sends the message
  5. SMS or supported iMessageChannel routing picks iMessage where supported, SMS otherwise
  6. CustomerThe message arrives; the customer can reply
  7. Delivery or reply eventSendiMessage records what actually happened
  8. Signed webhookYour endpoint receives outbound or receive
  9. HubSpot timeline updateYour handler writes the event back as activity

Example request

Workflow payload
{
  "number": "{{contact.phone}}",
  "content": "Hi {{contact.first_name}}, your appointment is tomorrow at 10:00 AM."
}

Template variables like {{contact.phone}} are illustrative — replace them with your platform's own merge syntax or values resolved by your middleware. Correlate delivery events by storing the returned message_handle on your own record.

Delivery events and incoming replies

Correlate delivery events with the message_handle you stored at send time (or with ids embedded in your per-message status_callback URL); replies carry the contact's number and conversation, which your middleware maps to the right HubSpot record. Automatic HubSpot synchronization is not built in — your handler (or automation platform) performs the write-back.

webhook event
// "outbound" event → your hubspot 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 contact_id in hubspot.

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.
  • A native HubSpot marketplace application is not available today. The integration methods on this page are API-based.
  • Send messages only to recipients who expect them. Transactional and operational messaging is the primary use case — unsolicited bulk marketing is not.

Security considerations

  • Store the SendiMessage API key in HubSpot's credential store, your middleware's secret manager, or your automation platform's connection vault — never in front-end scripts or record fields.
  • Verify the signature header on every webhook before writing anything back to the CRM.
  • Send only the fields the message needs (phone, first name); keep full CRM records out of message payloads and logs.

Frequently asked questions

Does SendiMessage have a native HubSpot application?
Not today. HubSpot connects through the SendiMessage REST API — via HubSpot Workflows (webhook or custom code actions), middleware, or an automation platform. This page is an API integration guide, and statuses on this site only say "native" when a native app has actually shipped.
Can HubSpot workflows send SMS through SendiMessage?
Yes — any HubSpot automation that can make an outbound HTTP request (directly or via middleware) can call POST /send-message. The response confirms the message is queued; delivery status follows on your webhook.
Can HubSpot trigger iMessage?
Delivery uses iMessage on supported messaging lines and destinations, with SMS fallback when configured. Not every contact supports iMessage, so treat it as an upgrade, not a guarantee.
Can customer replies return to the CRM?
Yes. Incoming replies arrive as receive webhook events carrying the contact's number and conversation. Your middleware or automation platform matches that to the HubSpot record and creates timeline activity or a task.
Do I need middleware?
Only if HubSpot Workflows (webhook or custom code actions) can't make the HTTP calls you need, or you want central consent logic and retry handling. Many teams start with workflow + HTTP or an automation platform and add middleware as volume grows.
Where should API credentials be stored?
Server-side only: the CRM's credential store, your middleware's secrets manager, or the automation platform's connection vault. Never in client-side scripts, record fields, or shared documents.
How is pricing calculated?
Per active messaging line, billed monthly, with usage according to your agreement. The team confirms per-line pricing for your countries and volume during onboarding.
Which HubSpot subscription do I need?
Workflow webhook actions and custom code actions are Operations Hub Professional features. Without them, an automation platform (Zapier, Make) or middleware listening to HubSpot webhooks achieves the same flow on any tier.

Ready to connect HubSpot?

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