How to load data from Square to SQL Data Warehouse

What is Square?

Square is a simple and powerful POS software for businesses. It is designed to run on multiple devices, ranging from smartphones to a merchant’s counter, without requiring specialized equipment. As a Point of Sale software, it takes care of:

Digital receipts from your customers
Your product inventory
Sales reports
Valuable analytics that you can use to understand the performance of your business better

Square is suitable for both big and small businesses and scales according to your needs as a product.

The Point of Sale software of Square is free to download and use, it charges on a per transaction basis. Square charges a flat, fixed rate of 2.75% of volume for all Visa, MasterCard, Discover, American Express, and other vendors transactions.

Additionally to the POS software, Square has a number of additional products, ranging from hardware that is needed for POS like:

Contactless chip readers to support EMV and NFC payments
MAGSTRIPE readers
or even stands to transform an iPad into a POS

to Payment and accounting related services like:

Payment processing
Invoice handling
Gift card management

Square has transformed from a POS software vendor to a complete payment platform which includes:

POS systems
Employee management
An app marketplace
Payroll services
and even appointment services

Finally, it offers a gateway to sell goods online, services to add the delivery for restaurants, and funding for small businesses.

As a platform, Square exposes a rich API that can be used to build applications that can be delivered via its app marketplace. This API is expressive enough to allow us to pull data that can be used for analytics. In this article, we will explore how we can use the Square API to pull this data.

How to Extract my data from Square?

As a platform, Square exposes a number of different APIs that cover different needs.

E-commerce API, with which you can take payments using
Register API, which can be used to build your own applications for in-store or mobile payments.
Item & inventory management API.
Sales reporting & Analytics API.
Employee management API.

Square is currently maintaining two versions of the API, Connect v1 and Connect v2. There’s also an SDK for the Register API. You might need to use both v1 and v2 of the Connect API, as not all endpoints have been implemented in the second and newest version. Mixing the two API versions is encouraged by Square.

All the APIs that Square exposes are web APIs. As Web APIs following the RESTful architecture principles, they can be accessed through HTTP. As a RESTful API, interacting with it can be achieved using tools like CURL or Postman or using HTTP clients for your favorite language or framework. A few suggestions:

Square also maintains official SDKs or libraries for the following languages:

Because of the popularity of Square, a number of unofficial libraries/SDKs are also implemented, so a quick search on Google or Github will help you find a library for your favorite framework or language.

Square API Authentication

In order to use the Square API you first need to register a new application with Square. By doing that you are also generating credentials that will be used to access the API endpoints.

To register your application:

Go to https://connect.squareup.com/apps and sign in to your Square account.
Click New Application and enter a name for your application.
Click Create App.

The application dashboard displays your new app’s credentials. One of these credentials is the personal access token. This token gives your application full access to your own Square account. Copy its value to use in the next step.

Square API Rate Limiting

If Connect API endpoints receive too many requests associated with the same application or access token in a short time window, they might respond with a 429 Too Many Requests error. If this occurs, try your request again at a later time. The current rate is on the order of 10 QPS. This might change in the future and is not officially documented to handle our requests and responses properly.

Pull Data From the Square Platform

As mentioned earlier, Square exposes a number of APIs for different applications. Thus, each one offers different opportunities for pulling useful data out of it. In this post, we will focus on how to get meaningful data out of the Square Connect API that can be used for analytics.

The Square Connect API allows us to use the Square platform to execute payment transactions, so many endpoints are related to these tasks. We do not need to access these endpoints for analytic purposes. In a payment system, what we need to track and use as data for further analysis is related to what is happening on our system. For example, we would like to track when a new payment had happened, when something went wrong with a transaction, etc. To do that, we need to monitor the system for specific events and make sure that we store these events in a data warehouse solution like SQL Data Warehouse for further analysis.

Square Connect API offers a notification through the Webhooks mechanism to receive notifications any time an important event happens in our system. We can use this mechanism to track and record events from the Square Platform for analytics. We can receive real-time webhook notifications as a merchant accepts payments. Get started with webhooks with the following steps:

Open your application’s settings from the application dashboard and select the Webhooks tab.
Click Enable Webhooks if it isn’t already enabled.
In the Notification URL field, specify the URL of your webhook page and click Save.
Subscribe to webhook notifications from your merchant account by sending the following curl request to the Update Webhooks endpoint (providing your access token and location ID where indicated):

SH
curl -X PUT -H "Authorization: Bearer PERSONAL_ACCESS_TOKEN" -H "Content-Type: application/json" -d "[\"PAYMENT_UPDATED\"]" https://connect.squareup.com/v1/LOCATION_ID/webhooks

By doing the above, we request the Square Connect API to notify us every time a new payment is happening to track these events. The API is near real-time, and you will receive the notification in no more than 60 seconds from the moment it happens.

The event that will be sent to our Webhook will look like this:

JSON
{
  "merchant_id": "18YC4JBH91E1H",
  "location_id": "JGHJ0343",
  "event_type": "PAYMENT_UPDATED",
  "entity_id": "Jq74mCczmFXk1tC10GB"
}

As the above event does not include information that can be used directly, we will have to extract the “entity_id” value and use it to poll the RetrieveTransaction endpoint to get the full details of the event. If we do that we will get a full response like the following:

JSON
{
  "transaction": {
    "id": "KnL67ZIwXCPtzOrqj0HrkxMF",
    "location_id": "18YC4JDH91E1H",
    "created_at": "2016-03-10T22:57:56Z",
    "tenders": [
      {
        "id": "MtZRYYdDrYNQbOvV7nbuBvMF",
        "location_id": "18YC4JDH91E1H",
        "transaction_id": "KnL67ZIwXCPtzOrqj0HrkxMF",
        "created_at": "2016-03-10T22:57:56Z",
        "note": "some optional note",
        "amount_money": {
          "amount": 5000,
          "currency": "USD"
        },
        "processing_fee_money": {
          "amount": 138,
          "currency": "USD"
        },
        "type": "CARD",
        "card_details": {
          "status": "CAPTURED",
          "card": {
            "card_brand": "VISA",
            "last_4": "1111"
          },
          "entry_method": "KEYED"
        }
      }
    ],
    "reference_id": "some optional reference id",
    "product": "EXTERNAL_API"
  }
}

This complete transaction object can be used for analysis purposes.

As we can see, getting data from the Square platform to do analytics requires both a pull and push logic where the platform first notifies us about events, and then we pull out the complete transaction object by performing requests to the API. This approach might make the whole process a bit complicated, especially if we consider that the above example covers just one event type. We would like to do that for every possible event that the platform tracks.

How can I Load my data from Square to SQL Data Warehouse?

SQL Data Warehouse supports numerous options for loading data, such as:

PolyBase
Azure Data Factory
BCP command-line utility
SQL Server integration services

As we are interested in loading data from online services by using their exposed HTTP APIs, we will not consider the usage of BCP command-line utility or SQL server integration in this guide. We’ll consider the case of loading our data as Azure storage Blobs and then use PolyBase to load the data into SQL Data Warehouse.

Accessing these services happens through HTTP APIs. APIs play an important role in both the extraction and the loading of data into our data warehouse. You can access these APIs by using a tool like CURL or Postman. Or use the libraries provided by Microsoft for your favorite language. Before you upload any data, you have to create a container that is similar to a concept to the Amazon AWS Bucket, creating a container is a straightforward operation, and you can do it by following the instructions found on the Blog storage documentation from Microsoft. As an example, the following code can create a container in Node.js.

JAVASCRIPT
blobSvc.createContainerIfNotExists('mycontainer', function(error, result, response){
  if(!error){
    // Container exists and allows
    // anonymous read access to blob
    // content and metadata within this container
  }
});

After the creation of the container you can start uploading data to it by using again the given SDK of your choice in a similar fashion:

JAVASCRIPT
blobSvc.createBlockBlobFromLocalFile('mycontainer', 'myblob', 'test.txt', function(error, result, response){
  if(!error){
    // file uploaded
  }
});

When you are done putting your data into Azure Blobs, you can load it into SQL Data Warehouse using PolyBase. To do that, you should follow the directions in the Load with PolyBase documentation. In summary, the required steps to do it are the following:

create a database master key
create a database scoped credentials
create an external file format
create an external data source

PolyBase’s ability to transparently parallelize loads from Azure Blob Storage will make it the fastest loading data tool. After configuring PolyBase, you can load data directly into your SQL Data Warehouse by simply creating an external table that points to your data in storage and then mapping it to a new table within SQL Data Warehouse.

Of course, you will need to establish a recurrent process that will extract any newly created data from your service, load them in the form of Azure Blobs and initiate the PolyBase process for importing the data again into SQL Data Warehouse. One way of doing this is by using the Azure Data Factory service. In case you would like to follow this path, you can read some good documentation on how to move data to and from Azure SQL Warehouse using Azure Data Factory.

What is the best way to load data from Square to SQL Data Warehouse? Which are the possible alternatives?

So far, we just scraped the surface of what can be done with Microsoft Azure SQL Data Warehouse and how to load data into it. The way to proceed relies heavily on the data you want to load, from which service they are coming from, and the requirements of your use case. Things can get even more complicated if you want to integrate data coming from different sources. Instead of writing, hosting, and maintaining a flexible data infrastructure, a possible alternative is to use a product like RudderStack to handle this kind of problem automatically.

RudderStack integrates with multiple sources or services like databases, CRM, email campaigns, analytics, and more.