Slow Sendy sending rate

Sendy seems very slow?

Some of our customers, especially with large email list or need for time-based campaigns, complain about slow sending speed of campaigns in Sendy.

This can be quite frustrating especially when you are launching an offer or it is a Black Friday sale campaign.

The goto solution for them is increasing the size of the server - either VPS or EC2 instance. The assumption is - adding more cores will speed up the campaign.

‍

Why big servers are not faster?

There are a lot of factors affecting the campaign sending speeds. Here are a few that play a major role -

1. Number of cores – how many emails can run concurrently?
2. Code efficiency – is Sendy actually using those cores for both sending and database operations?
3. Email size – does the server have enough RAM to handle longer emails?
4. List size & database indexing – are the right indexes in place so the code can run through large lists quickly?

This means that the hypothesis of "double the server = fast campaign" will not always be true.

‍

What actually speeds up the campaign?

There is no size fits all solution. At Sendybay, we've few generic optimisations that allow for faster sending speed, averaging anywhere from 30-60 emails per seconds. The variability comes from size of the list, size of the campaign.

In addition, when we've a particularly heavy user, we'll white glove their setup to fine tune performance. This often requires adding the right indexes or customising the code to make sure the features they need run extremely fast.

‍

If you are struggling with Sendy sending speed, reach out to us at support@sendybay.com and we will share tips on what will move the needle.

‍