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Channels help you organize your Helo account into separate sending environments — with dedicated stats, dedicated reputation, and dedicated controls. Channels come in handy when you:
  • Are a platform sender and need to separate email sending for different customers
  • Need to create testing environments (we call these Sandbox Channels)
  • Want to separate different types of emails you’re sending (for example to view aggregated stats)
  • Or really any use cases that make you want to create dedicated sending environments.

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How to create a channel

TODO

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Sandbox channels

Sandbox Channels your safe, self-contained space to develop and test email integrations without sending to real inboxes. A Sandbox Channel behaves exactly like a regular Channel—you can send through the API or SMTP, inspect messages, trigger webhooks, and check stats—except the emails never leave Helo.

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What Sandbox Channels are good for

  • Building your integration - Test your API calls, SMTP setup, and payload formatting without worrying about test emails landing in someone’s inbox.
  • Checking templates - Send real messages through the API and inspect them in the Helo dashboard to confirm they are working correctly.
  • Testing webhooks — Sandbox messages trigger delivery webhooks just like live messages do, so you can build and test your webhook handlers end-to-end.
  • Supporting QA and staging environments — Point your staging app at a Sandbox Channel so your team can test freely without any risk.

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How it works

Sandbox Channels process messages through Helo’s infrastructure the same way live sends do. That means:
  • Messages show up as Delivered in your dashboard and via the API (even though we don’t actually deliver them to real inboxes)
  • All message metadata (headers, recipient, subject, body) is stored and inspectable
  • Delivery webhooks fire normally
  • Bounce simulation is supported (see simulating bounces)
Heads up: Because Sandbox messages are processed through Helo’s infrastructure, they do count toward your monthly sending budget, just like live messages.

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Creating a Sandbox Channel

When creating a new Channel, you’ll be asked to choose a type:
  • Live — for production sending
  • Sandbox — for testing
The new channel dialog
You can also change the Channel type of an existing Channel. To do that, select the Channel you’d like to update and change its type in the Channel Settings.
Tip: Create API credentials that work with your Sandbox Channel. When setting up new API credentials, you can decide to scope them to a single Channel only. Set up dedicated credentials that work with your Sandbox environment only to further isolate your testing environments.

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Creating a Sandbox Channel via the API

You can also create a Sandbox Channel programmatically using the Channels API. Pass "delivery_type": "sandbox" in your request body:
cURL
curl --location 'https://api.helohq.com/channels' \
--header 'Content-Type: application/json' \
--header 'Accept: application/json' \
--header 'Authorization: Bearer YOUR_API_KEY' \
--data '{
  "deliveryType": "sandbox",
  "name": "Channel name"
}'
If delivery_type is omitted, it defaults to live.