Definition
An email frequency cap is a rule that limits how many messages a subscriber can receive within a set period, such as one email per day or three per week. It prevents the send engine from over-mailing any single recipient, even when multiple automated campaigns could each fire for them.
Caps matter because over-sending causes fatigue, unsubscribes and spam complaints. A cap is a form of protection: no matter how many campaigns and triggers a programme runs, no subscriber receives more than the agreed limit.
How a Frequency Cap Works
| Setting | Effect |
|---|---|
| Cap per period | Maximum emails per day/week/month |
| Global vs per-flow | Applies across all sends or within one |
| Suppression during cap | Drops or queues mail that exceeds the cap |
| Priority rules | Decides which mail wins when capped |
A cap is enforced at send time, so skimming recent sends decides whether an email goes out.
Why Frequency Caps Matter
- Prevents fatigue: Stops subscribers being overwhelmed by volume.
- Reduces complaints: Less unwanted email means fewer spam reports.
- Protects reputation: Engaged, un-capped-subscribed recipients support delivery.
- Balances campaigns: Stops an automated trigger stacking on a promotional send.
How to Set an Email Frequency Cap
- Set a base cap by period: Choose a sensible default for your audience and type.
- Align across channels: Cap email, not just each individual campaign.
- Override for priority messages: Let urgent transactional mail bypass the marketing cap.
- Track fatigue indicators: Watch opens and complaints to tune the cap.
Related Glossary Terms
Account-Based Marketing Email
An account-based marketing email is a highly targeted message sent to a specific organisation or decision-maker group as part of a focused B2B strategy.
Announcement Email
An announcement email is a dedicated campaign that communicates a specific update, milestone, or change to subscribers, from product launches and feature releases to company news and events.
B2B Email Marketing
B2B email marketing targets business professionals and organisations with longer sales cycles, educational content, and relationship-driven campaigns compared to B2C email.
B2C Email Marketing
B2C email marketing focuses on sending targeted promotional and transactional emails to individual consumers, emphasising personalisation, urgency, and direct response.
Behavioral Email
Behavioral email is a message triggered by a subscriber's action, inaction, or engagement pattern, making it more relevant than scheduled broadcast sends.
Behavioral Segmentation
Behavioral segmentation is the practice of grouping subscribers based on their actions, such as opens, clicks, purchases, browsing and engagement patterns.
Frequently Asked Questions
An email frequency cap is a rule limiting how many messages a subscriber can receive in a set period, such as one a day. It stops the send engine from over-mailing any individual, even across multiple campaigns.
Without one, automated triggers and promotional sends can stack, flooding subscribers and causing fatigue, unsubscribes and complaints. A cap protects the recipient and the sender's reputation.
Over-sending damages engagement and drives complaints, both of which hurt reputation and inbox placement. By keeping volume within comfortable limits, a cap preserves engagement and delivery quality.
Often it should be exempt. Recipients expect transactional email such as receipts and confirmations immediately, and exempting it ensures critical messages still arrive regardless of the marketing cap.