Why did my Mailjet emails sent suddenly jump?
The Mailjet help pages give 4 common reasons. The first to rule out: A workflow can start when contacts join a list, so adding many contacts to a list at once can start many workflow emails together.
Is it broken, or just quiet?
A number can fall because fewer people came, or because something stopped counting them. Below are the causes the Mailjet help pages give, and how to check each one yourself.
What causes it?
A workflow can start when contacts join a list, so adding many contacts to a list at once can start many workflow emails together.
In the Mailjet help:
Subscription event: Trigger workflow when contacts subscribe to one, many, or all contact lists.
Email Automation, read 2026-11-12.A workflow can start when a contact detail changes, so a bulk change to contact details can set off emails for many contacts.
In the Mailjet help:
Contact Property Update (CPU) event: Trigger workflow when a contact property is updated.
Email Automation, read 2026-11-12.When a workflow is published, it can include your existing contacts, not only new ones, so publishing can bring a burst of emails.
In the Mailjet help:
or to also include existing contacts by checking them against the start block criteria.
Email Automation, read 2026-11-12.Your website, app or CRM can start workflows by reporting events to Mailjet, so a spike in those events can raise emails sent.
In the Mailjet help:
External event (Webhook): Trigger a workflow when your system (website, app, CRM, etc.) sends an event to Mailjet via API.
Email Automation, read 2026-11-12.
How do I check it myself?
Look at the stats for each email in your workflows to see which one accounts for the extra emails.
In the Mailjet help:
If your flow sends multiple emails, review each Send Email for stats.
Email Automation, read 2026-11-12.Workflow stats can take a short time to catch up, so look again a little later before comparing them with the day's total.
In the Mailjet help:
Stats appear after the first contact enters the workflow and may take a short time to update.
Email Automation, read 2026-11-12.
How would I know the day it starts?
- Feder reads your emails sent from Mailjet each day and compares each day with your own history.
- It tells you when emails sent go quiet or move outside their usual range.
Some numbers are too quiet to judge daily, such as a form filled in a few times a week. Until there is enough of your own history to judge a change, Feder says it is still learning and scores nothing, rather than guessing.
See what Feder reads from Mailjet, which feeds Reach. Feder only reads. It never changes anything in Mailjet.
What else goes wrong with these numbers?
- Why did my Mailjet email clicks drop?Mailjet
- Why did my Mailjet emails sent drop?Mailjet
- Why did Google Analytics stop collecting data?Google Analytics
- Why aren't my key events showing in Google Analytics?Google Analytics
- Why does Google Analytics show (not set)?Google Analytics
See every question.
Where do these answers come from?
Every cause and check on this page comes from the Mailjet help pages, quoted above with the date we read them. Last reviewed 2026-11-12. We read them again by 2027-11-12. If one changes, this page changes or comes down.