Quick Start: Subscribing to Webhook Topics

The following guide outlines how to subscribe to webhook events from Newline. If you're new to webhook implementations, this section will help you get started with the required setup and best practices.

• Clients must register for each webhook topic they wish to receive events from. Topics are structured using a segmented naming convention, such as:

  abc-enterprises.sandbox.transaction
  

Newline will work with you to define the appropriate topics and will share the final topic names for registration.

• To subscribe, clients must provide the following to the Newline Onboarding Support (NOS) team:

• A Base URL where webhook events will be delivered (must be HTTPS)

• A public encryption key

• A list of topics they wish to subscribe to

• Newline will issue an HMAC key used to sign each webhook event. Clients must validate this signature to ensure authenticity.

• Each webhook event includes a unique event ID in the header. Clients should implement idempotency checks to avoid processing the same event more than once.

• Webhook endpoints must respond within 5 seconds. If no response is received, Newline will retry delivery up to 3 times. If all retries fail, Newline may call a health check endpoint (recommended path: /webhooks/health).

• Clients should test their webhook implementation in the sandbox environment before going live. Once validated, they can transition to the production environment by providing the production Base URL and confirming the topic list.

Unsubscribing from a Webhook Topic

Clients can unsubscribe from webhook topics by contacting the Newline Onboarding Support (NOS) team and specifying the topics or events they wish to stop receiving. Newline will update or terminate the subscription accordingly.