Xero to BigQuery

This page provides you with instructions on how to extract data from Xero and load it into Google BigQuery. (If this manual process sounds onerous, check out Stitch, which can do all the heavy lifting for you in just a few clicks.)

What is Xero?

Xero offers cloud-based accounting software for small and medium-sized businesses.

What is Google BigQuery?

Google BigQuery is a data warehouse that delivers super-fast results from SQL queries, which it accomplishes using a powerful engine dubbed Dremel. With BigQuery, there's no spinning up (and down) clusters of machines as you work with your data. With that said, it's clear why some claim that BigQuery prioritizes querying over administration. It's super fast, and that's the reason why most folks use it.

Getting data out of Xero

Xero provides a REST API that lets you get accounting, payroll, asset, and other information stored in the system. To get a list of payments from the Accounting element, for instance, you could call GET /api.xro/2.0/Payments/. This call has four optional parameters that let you filter and sort the data being returned.

Sample Xero data

The Xero API returns data in XML format. For example, the result of a call to retrieve a particular payment might look like this:

<Payment>
  <PaymentID>b26fd49a-cbae-470a-a8f8-bcbc119e0379</PaymentID>
  <Date>2016-12-12T00:00:00</Date>
  <Amount>281.25</Amount>
  <CurrencyRate>1.000000</CurrencyRate>
  <PaymentType>ACCRECPAYMENT</PaymentType>
  <Status>AUTHORISED</Status>
  <UpdatedDateUTC>2017-02-20T08:22:27.847</UpdatedDateUTC>
  <IsReconciled>true</IsReconciled>
  <Account>
    <AccountID>297c2dc5-cc47-4afd-8ec8-74990b8761e9</AccountID>
  </Account>
  <Invoice>
    <Contact>
      <ContactID>3e1d3ba5-609a-4e10-bb1d-75b6d31ce922</ContactID>
      <Name>Seymour Grimes</Name>
    </Contact>
    <Type>ACCREC</Type>
    <InvoiceID>d3cb96c6-8f3a-45ec-a261-0a7b65d4b877</InvoiceID>
    <InvoiceNumber>OIT00504</InvoiceNumber>
  </Invoice>
</Payment>

Preparing Xero data

If you don't already have a data structure in which to store the data you retrieve, you'll have to create a schema for your data tables. Then, for each value in the response, you'll need to identify a predefined datatype (INTEGER, DATETIME, etc.) and build a table that can receive them. Xero's documentation should tell you what fields are provided by each endpoint, along with their corresponding datatypes.

Complicating things is the fact that the records retrieved from the source may not always be "flat" – some of the objects may actually be lists. This means you'll likely have to create additional tables to capture the unpredictable cardinality in each record.

Loading data into Google BigQuery

Google Cloud Platform offers a helpful guide for loading data into BigQuery. You can use the bq command-line tool to upload the files to your awaiting datasets, adding the correct schema and data type information along the way. The bq load command is your friend here. You can find the syntax in the bq command-line tool quickstart guide. Iterate through this process as many times as it takes to load all of your tables into BigQuery.

Keeping Xero data up to data

At this point you've coded up a script or written a program to get the data you want and successfully moved it into your data warehouse. But how will you load new or updated data? It's not a good idea to replicate all of your data each time you have updated records. That process would be painfully slow and resource-intensive.

Instead, identify key fields that your script can use to bookmark its progression through the data and use to pick up where it left off as it looks for updated data. Auto-incrementing fields such as updated_at or created_at work best for this. When you've built in this functionality, you can set up your script as a cron job or continuous loop to get new data as it appears in Xero.

And remember, as with any code, once you write it, you have to maintain it. If Xero modifies its API, or the API sends a field with a datatype your code doesn't recognize, you may have to modify the script. If your users want slightly different information, you definitely will have to.

Other data warehouse options

BigQuery is great, but sometimes you need to optimize for different things when you're choosing a data warehouse. Some folks choose to go with Amazon Redshift, PostgreSQL, or Snowflake, which are RDBMSes that use similar SQL syntax, or Panoply, which works with Redshift instances. If you're interested in seeing the relevant steps for loading data into one of these platforms, check out To Redshift, To Postgres, To Snowflake, and To Panoply.

Easier and faster alternatives

If all this sounds a bit overwhelming, don’t be alarmed. If you have all the skills necessary to go through this process, chances are building and maintaining a script like this isn’t a very high-leverage use of your time.

Thankfully, products like Stitch were built to solve this problem automatically. With just a few clicks, Stitch starts extracting your Xero data via the API, structuring it in a way that is optimized for analysis, and inserting that data into your Google BigQuery data warehouse.