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Frequently asked questions about using PHLO (Plivo High Level Objects) for SMS workflows.

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What is PHLO?

PHLO provides a visual workflow builder for messaging automation without writing code. Common use cases include:
  • Forwarding incoming SMS to another number
  • Auto-responding to inbound messages
  • Tracking outbound message delivery status

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How can I forward messages to Plivo numbers using PHLO?

  1. Create a new PHLO
  2. Add a Send SMS node connected to Incoming SMS in the start node
  3. Rename the node (e.g., “Forward_SMS”)
  4. Configure the node:
FieldValue
From{{Start.message.from}} (dynamic) or a valid Plivo number (static)
ToYour destination number
Message{{Start.message.text}} (forwards original message)
  1. Click Validate to save
  2. Click Save
  3. Attach the PHLO to an SMS-enabled Plivo number
Note: Using {{Start.message.from}} takes the actual source from the received message. If the source is a short code not rented in your account, forwarding will fail. Using a Plivo number in the From field is recommended.

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How do I set up an autoresponder for inbound SMS?

  1. Create a new PHLO
  2. Connect a Send SMS node to Incoming SMS in the start node
  3. Configure the node:
FieldValue
From{{Start.message.to}} (the Plivo number that received the message)
To{{Start.message.from}} (the sender’s number)
MessageYour auto-reply text
  1. Click Validate and Save
  2. Attach the PHLO to your Plivo number
See Getting Started with SMS Autoresponder for detailed configuration.

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How do I receive message details for an outbound SMS?

Use the Event Callbacks option in the Send SMS component:
  1. In your PHLO, select the Send SMS component
  2. Locate the Event Callbacks option
  3. Add your callback URL
  4. Select which message states to receive callbacks for

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Available Status Events

StatusDescription
queuedMessage accepted, waiting to send
sentMessage sent to carrier
deliveredConfirmed delivery to recipient
undeliveredFailed to deliver
failedError occurred before sending
Each selected status triggers a callback to your URL with message details.

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What variables can I use in PHLO for messaging?

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Inbound Message Variables

VariableDescription
{{Start.message.from}}Sender’s phone number
{{Start.message.to}}Plivo number that received the message
{{Start.message.text}}Message content
Variables can be used in any text field within PHLO nodes including message content, From/To fields, and callback URLs.

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How do I attach a PHLO to a phone number?

Via Phone Number:
  1. Navigate to Phone Numbers > Active
  2. Click on your phone number
  3. Select PHLO for Application Type
  4. Choose your PHLO from the dropdown
  5. Click Update
Via Powerpack:
  1. Navigate to your Powerpack
  2. In Application Configuration, select PHLO
  3. Select your PHLO application
  4. Update