As the hosting operator, use a separate Test / Debug gateway in Log only mode to rehearse your notification text, templates and event routing. It records a result in History without sending an SMS or making a Twilio API request.

Add the rehearsal gateway

1. Open PD Modules → Twilio SMS → Gateways → Add a gateway.
2. Choose Test / Debug and give it an obvious rehearsal name.
3. Set Mode to Log only (record in History, send nothing).
4. Leave Simulate failure off for the first successful rehearsal and save.

Email the message to an admin is a different mode: it sends preview email. Leaving its destination blank can send to active administrators. Choose Log only if the intention is to rehearse without either email or SMS.

Check the intended workflow

Open Send SMS, use a controlled test recipient and select the rehearsal gateway explicitly under Send via. Enter the intended Message and choose Count segments before submitting the rehearsal. If a template fills the composer, inspect the text and replace placeholders before a manual send rather than assuming every merge field will resolve there.

Review History for the selected gateway, recorded text and result. A successful Test / Debug record is not evidence that Twilio authentication, sender selection or delivery works. It deliberately avoids those provider operations.

For an automatic workflow, explicitly select the rehearsal gateway on the intended test trigger and review the client’s category preference, queue and quiet hours. Do not generate real invoices, ticket replies or service actions merely to test a notification on a live installation.

Keep rehearsal and live routing distinct

Setting up a test gateway does not redirect every existing trigger or campaign to it. Changing the default gateway can affect workflows that use Default routing, so inspect them before switching it. Keep a useful rehearsal gateway available rather than deleting it simply because a live sender is ready.

If testing error handling, Simulate failure deliberately makes the test fail. Review that setting before interpreting a failure as a module defect. An intended Send test SMS through the Twilio gateway is a separate real action and may incur provider charges.

See the PD Twilio SMS WHMCS guide for related tasks, or explore PD Twilio SMS.