Building a Great Email Schema | Part 3: Batch or API

You’ve now got a great idea of what kind of data you need to send top notch emails. You’ve even worked to identify the specific data points and associated values that will help you target your emails really effectively. Well that’s all theory until you get that information into your email service provider (ESP) to begin using it. So let’s make the jump from theory to practice.

There are generally two ways by which you can exchange data with your email service provider: batch or API. Neither is perfect. Here’s a quick rundown of each.


This method of data exchange is basically what it sounds like: aggregating all the information that needs to be exchanged and delivering it all at once – like in a big batch. Your technical team will have to help you build a process that identifies when the data points you need change and trigger the inclusion of said data points in your file.

It’s common to exchange information with your ESP once a day through the batch process, typically kicking off in the overnight hours to give your internal systems enough time to build the file and load it into your ESP. This does means there is some latency between when your users will make an update and when your email system will reflect those updates. CAN-SPAM compliance in the US gives businesses 10 days to honor an opt out request, so the once daily batch process to capture changes, including opt outs is well within the legal boundaries.


API, or application programming interface, is a more real-time method to exchange the data you need with your ESP. Instead of a once-daily process through a batch file, the API will expose the changes to your ESP in real time as they happen in your systems. Your ESP can then record those changes to act upon them via email.

APIs are great, but require significant development efforts and may be more limited in terms of the types of data you can include.

Now, you’re probably thinking – what about triggered emails, like order confirmation or shipping emails? Anything triggered has to happen via API as by definition, it needs to be real time. So even if you choose to use the batch method of delivery, you’ll still likely have to work with your team to build some API processes to address your triggered email needs.

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