Memo Bank Webhook API

# EventsWhen something interesting happens on your Memo Bank workspace, such as a new transaction being created, Memo Bank can reach out to your application so that you can take action (such as sending an e-mail alert about the transaction to your user) automatically.The first step is to add a webhook to your application in the [`API`](https://client.memo.bank/api) section of your Memo Bank workspace. As part of this, you will have to provide a URL on your own servers. Memo Bank will then send HTTPS requests to that URL when there is an activity on your Memo Bank workspace.Note that even if webhooks are setup within an application, events will be received even when they result from actions triggered on the Memo Bank webapp or any other application.# Consuming eventsIndividual events do not contain very much information on their own. This is by design, as the API structure can remain extremely stable and avoid difficult webhook migrations in the future as the Memo Bank API changes. If you need additional metadata, such as the amount of the transaction in the above example, make a `GET` request to the API for that information. You can use the `resource_type` and `resource_id` to determine what resource to fetch from the API.# Failures and retriesIf your application returns anything other than a 2xx HTTP status code, if we do not receive a response before timing out or in the case of a network failure, we will retry the event up to 8 times with exponentially increasing backoffs. In your webhook endpoint implementation, we recommend you place inbound Events into your application's own queuing system (such as Kafka, Resque, etc) for asynchronous event processing, and returning a 200 response from your endpoint as quickly as possible.Since retries may occur, your webhook endpoint must be idempotent. You should handle the possibility of receiving the same event multiple times. We recommend using the event `id` field to detect and ignore duplicate events on your side.# Securing your webhook endpoint (recommended)Memo Bank will include an `Authorization` header in each webhook request. Inside of it, you will find `Bearer ` with the authentication token we provided when you created the webhook on the web interface. We recommend that you check this header and reject requests with invalid token, indicating a malicious request that would not have been issued by Memo Bank.We also recommend that you restrict which IP addresses can call your webhook. Here is the list of our IPv4 addresses:* Memo Bank Premium API (i.e. `api.memo.bank`): * `34.38.96.206` * `35.189.206.171` * `35.241.129.224` * `34.155.214.185` * `34.155.206.98` * `34.163.14.38`* Memo Bank Premium Sandbox API (i.e. `api.sandbox.memo.bank`): * `34.155.60.111` * `34.163.27.39`