What are Postbacks?

Postback (Web Callback, HTTP Push API, or Reverse API) is a one-way web application that can send information to another application in real time when a specific event happens.

Example

If you have subscribed to the tds.206-ab.done webhook event, you will receive a notification every time your 206AB Job is done.

Endpoint

    

Postback Vs. API

APIs send you the data when you request it. For Postback, you do not need to make a request. You receive the data when it is available.

Example

If you need to know whether the TDS is filed or not, using APIs you need to keep polling every few seconds until it gets e-filed. While if you are using Postback, you can configure a postback event tds.efile.done to receive notifications when your TDS is filed.

Configure Postbacks

Postback Configuration events can be set by sending an API request and pointing out the events for which you would like to receive a Postback. At the same time, you can configure them from your account dashboard as well.

Validating Postbacks

When your Postback secret is set, We use it to create a hash signature with each payload. The secret is a string that can be decided upon by the user while configuring their Postback Notifications.

With each request, this hash signature is passed under thex-sandbox-signature in the request header using base64 encoding that needs to be validated at your end by reproducing the same hash key using the hmacsha256 algorithm.