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Set testMode: true when you need Signal to validate and record a send without handing it to the delivery provider. Test mode is an API field; it is not a project-wide dashboard switch.

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What test mode proves

  • The API key authenticates and has send permission.
  • The JSON request passes Signal validation.
  • Signal can create the customer-visible message record.
  • Your application can persist and correlate the response.
  • Your read and operational tooling can identify a test message.

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What it does not prove

  • DNS authentication is accepted by external mailbox providers.
  • The provider can deliver to the recipient domain.
  • The message reaches an inbox.
  • Open or click tracking behaves in a real mail client.
  • Your bounce and complaint handling sees a real provider event.

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Find the test

Open Emails and select the recorded message. The detail identifies test mode and shows test state rather than real provider delivery. Use a distinctive tag, metadata value, subject, and idempotency key so smoke tests are easy to separate from production activity.

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Test in layers

  1. Use test mode in automated deployment checks.
  2. Send a controlled real message to an inbox your team owns.
  3. Verify the signed webhook path with the endpoint test action.
  4. Monitor real delivery metrics after rollout.
Do not build a production delivery guarantee around test mode. It intentionally stops before provider delivery.

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SDK example

Start with the basic send example, then enable test mode in the request model for your SDK. Add the test-mode field to the normal SendEmailRequest.
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