Sandbox Testing

Test your SMS integration without sending real messages or using credits.

How It Works

Use a test API key (sk_test_*) instead of a live key
Send to magic phone numbers that simulate different scenarios
Receive realistic responses without actual SMS delivery

Magic Phone Numbers

Phone Number	Behavior
+15005550000	Always succeeds - simulates successful delivery
+15005550001	Invalid number error
+15005550002	Cannot route error
+15005550003	Insufficient credits error
+15005550004	Rate limited error
+15005550005	Delivery delayed (webhook sent after 30s)
+15005550006	Carrier rejected error

Example Test Request

curl -X POST https://sendly.live/api/v1/messages \
  -H "Authorization: Bearer sk_test_YOUR_TEST_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "to": "+15005550000",
    "text": "Test message",
    "messageType": "transactional"
  }'

Test vs Live Keys

Feature	Test Keys (sk_test_*)	Live Keys (sk_live_*)
Real SMS sent	No	Yes
Credits used	No	Yes
Magic numbers work	Yes	No
Webhooks fired	Yes (simulated)	Yes (real)

Testing Webhooks

Use the CLI to test webhooks locally:

npx @sendly/cli webhooks listen

This creates a tunnel and forwards webhook events to your local server.