Generic

Generic Channel

The Generic channel connects your own messaging system to a Pearl Text agent. Use it with a web chat, mobile app, CRM inbox, or any custom platform instead of one of NLPearl’s built-in integrations. The integration uses two webhooks:

Your system  ──POST──▶  NLPearl inbound URL      (user messages and control actions)
Your system  ◀──POST──  Your outbound URL        (Pearl replies and events)

The exchange is asynchronous. When you send a user message, NLPearl immediately returns 202 Accepted. Pearl’s reply is delivered shortly afterward as a separate POST request to your outbound URL.

Set Up the Channel

Open Text Channels

On the platform, go to Settings, open Text Channels, then find Generic and click Connect Generic.

Generic option highlighted on the Text Channels settings page

Configure your endpoint

Enter the details NLPearl will use to send events to your system:

Setting	Description
Channel Name	A name that helps you identify this connection on the platform.
Outbound URL	An HTTPS endpoint that receives Pearl replies, typing indicators, handoffs, and conversation events.
Auth Header (optional)	A custom header name and value that NLPearl includes in every request to your outbound URL, such as your own bearer token.

Connect Generic Channel dialog with channel name, outbound URL, and optional auth header fields

Save your channel credentials

Click Connect Channel. Open the connected channel to access the credentials required by your integration:

Value	Description
Channel ID	Identifies the channel and forms part of its inbound URLs.
Signing Secret	Authenticates requests in both directions. Send it with every request to NLPearl, and use it to verify requests sent to your outbound URL.

Generic Channel details dialog showing the Channel ID and Signing Secret

Treat the signing secret like a password. Never expose it in client-side code or commit it to source control.

Assign the channel to a Pearl

Open the Pearl that should handle these conversations. From its Overview page, open Settings, select Text Channel, and choose the Generic channel you created.

Text Channel field highlighted in the Pearl Overview settings

Your inbound base URL is:

https://text.inbound.platform.nlpearl.ai/Generic/{channelId}

Send Requests to NLPearl

Send every request as JSON and include the channel secret:

Content-Type: application/json
X-Pearl-Secret: <your-channel-secret>

Send a User Message

Send a user message to:

POST {baseUrl}/Message

{
  "messageId": "m-12345",
  "chatId": "+1234567890",
  "senderName": "Jane Doe",
  "timestamp": "2026-07-17T09:30:00Z",
  "text": "Hi, I need help with my order",
  "attachments": [
    {
      "url": "https://your.cdn.example/receipt.jpg",
      "contentType": "image/jpeg",
      "filename": "receipt.jpg"
    }
  ]
}

Field	Required	Description
`chatId`	Yes	Your conversation identifier, phone number, or end-user ID. Messages with the same value belong to the same conversation. Maximum 200 characters.
`messageId`	No	Your unique message identifier. Include it so NLPearl can deduplicate retries. Maximum 200 characters.
`senderName`	No	The sender name displayed in the transcript.
`timestamp`	No	The message time as an ISO 8601 timestamp. Defaults to the current time.
`text`	No	The message text, up to 8,000 characters.
`attachments`	No	Up to five publicly accessible image, audio, PDF, or text files. Each file can be up to 20 MB.

chatId is the conversation key. Every message with the same chatId belongs to the same conversation, and every outbound event for that conversation includes it.

Possible responses:

Status	Meaning
`202`	The message was accepted for asynchronous processing.
`400`	The payload is invalid, or the channel is not connected to a running Pearl.
`401`	The channel secret is invalid.
`404`	The channel does not exist.
`500`	A transient error occurred. You can safely retry when you provide a stable `messageId`.

Return Control to Pearl

After a human handoff, return the conversation to Pearl:

POST {baseUrl}/HandoffToPearl

{
  "chatId": "+1234567890"
}

End a Conversation

Close a conversation:

POST {baseUrl}/EndConversation

{
  "chatId": "+1234567890"
}

Both control actions return 200 when successful or 404 when no active conversation exists for the supplied chatId.

Receive Events from NLPearl

NLPearl sends each event to your outbound URL as a POST request with this envelope:

{
  "type": "message",
  "channelId": "6a59f7e02254e81f5533f11d",
  "chatId": "+1234567890",
  "timestamp": "2026-07-17T09:30:02.1234567Z",
  "data": {}
}

Event Types

`type`	`data`	Meaning
`message`	`{ "messageId", "text" }`	Pearl’s reply. Deliver it to your user.
`typing`	None	Pearl is composing a response. You can display a typing indicator.
`handoff`	`{ "reason", "riskReason"? }`	Pearl handed the conversation to a human. `reason` can be `agent_handoff`, `risk`, `max_turns_reached`, or `manual`.
`ai_resumed`	None	Pearl resumed control of the conversation.
`conversation_ended`	None	The conversation was closed by Pearl, because of inactivity, or through `EndConversation`.

New event types may be added over time. Ignore types your integration does not recognize.

Acknowledge Message Delivery

Your HTTP response controls delivery retries for message events:

Your status	NLPearl behavior
`2xx`	The message is marked as delivered.
`429`	Delivery is retried with backoff.
`408`, `5xx`, or timeout	Delivery is retried with backoff, then marked as failed if all attempts fail.
Other `4xx`	The failure is treated as permanent and is not retried.

Other event types, including typing and handoff, are best-effort notifications and are not retried.

Verify Webhook Signatures

NLPearl includes these headers in every request to your outbound URL:

X-Pearl-Timestamp: 1784281802
X-Pearl-Signature: 3f1a9c...

The signature is the hexadecimal result of:

HMAC-SHA256(secret, "{timestamp}.{rawBody}")

Verify the signature and reject old timestamps to protect your endpoint against forged requests and replay attacks:

const crypto = require("crypto");

function verifyPearlWebhook(req, rawBody, secret) {
  const timestamp = req.headers["x-pearl-timestamp"];
  const signature = req.headers["x-pearl-signature"];

  if (!timestamp || !signature) {
    return false;
  }

  const expected = crypto
    .createHmac("sha256", secret)
    .update(`${timestamp}.${rawBody}`)
    .digest("hex");

  const signatureBuffer = Buffer.from(signature, "hex");
  const expectedBuffer = Buffer.from(expected, "hex");

  return (
    signatureBuffer.length === expectedBuffer.length &&
    crypto.timingSafeEqual(signatureBuffer, expectedBuffer) &&
    Math.abs(Date.now() / 1000 - Number(timestamp)) < 300
  );
}

Compute the HMAC over the raw request body bytes before parsing the JSON. Re-serializing a parsed body can change its bytes and invalidate the signature.

If you configured a custom authentication header, NLPearl includes it alongside the signature headers.

Handle Human Handoffs

Receive the handoff

Pearl sends a handoff event with the reason it stepped aside.

Continue forwarding user messages

Let your human agent communicate with the user in your own system. Continue sending the user’s messages to /Message; Pearl remains silent while handed off, but the transcript and inactivity timers stay up to date.

Finish the handoff

Call /HandoffToPearl when Pearl should resume, or /EndConversation when the conversation is complete. Your endpoint then receives ai_resumed or conversation_ended, respectively.

Rotate the Secret

Open the connected Generic channel and click the rotate icon beside the Signing Secret to generate a new one.

Rotate Signing Secret button in the Generic Channel details dialog

The previous secret becomes invalid immediately. Update the secret used for both the X-Pearl-Secret request header and webhook signature verification at the same time. Otherwise, your inbound requests and outbound webhook verification will fail until both sides use the new value.

Limits

Limit	Value
Text length	8,000 characters
Attachments per message	5
Attachment size	20 MB each
`chatId` length	200 characters
`messageId` length	200 characters

The channel must be assigned to a running Pearl. If the Pearl is stopped or no Pearl is connected, inbound calls return 400 with "This channel is not connected to a Pearl.".

Inbound

Configure how your Pearl handles incoming conversations, inactivity, transcripts, and webhooks.

Getting Started

General

Pearl Voice

Pearl Text

Settings

Generic Channel

Set Up the Channel

Send Requests to NLPearl

Send a User Message

Return Control to Pearl

End a Conversation

Receive Events from NLPearl

Event Types

Acknowledge Message Delivery

Verify Webhook Signatures

Handle Human Handoffs

Rotate the Secret

Limits

Inbound

​Generic Channel

​Set Up the Channel

​Send Requests to NLPearl

​Send a User Message

​Return Control to Pearl

​End a Conversation

​Receive Events from NLPearl

​Event Types

​Acknowledge Message Delivery

​Verify Webhook Signatures

​Handle Human Handoffs

​Rotate the Secret

​Limits

Inbound

Generic Channel

Set Up the Channel

Send Requests to NLPearl

Send a User Message

Return Control to Pearl

End a Conversation

Receive Events from NLPearl

Event Types

Acknowledge Message Delivery

Verify Webhook Signatures

Handle Human Handoffs

Rotate the Secret

Limits