This article is part of a series that answers newsletter questions we often hear from users. Send us any questions you'd like to answer!

Email service providers (ESPs) and mailbox providers are extremely good at filtering and blocking spam. But that comes with a cost. Emails must play by the rules set by these gatekeepers to avoid being tagged as spam. One of those rules pertains to newsletter cadence. 

ESPs do not spell out exactly what they want to see from a good-faith sender. So although it’s not a hard and fast rule, crowdsourced data indicates that if you send your newsletter weekly or monthly and your spam complaints are below 0.1%, your publishing schedule won’t be a deliverability issue. The same goes for anyone sending to fewer than a thousand subscribers. However, for newsletters that go out multiple times per week, less than once a month, or to very large lists, deliverability might improve with changes to sending cadence.

How newsletter cadence affects deliverability and domain reputation

New senders live in something of a limbo zone, neither trusted nor distrusted, until ESPs have enough data to decide one way or the other. That’s why one of the most common pieces of advice for improving deliverability is to “warm up” your email address. Spammers spin up new addresses and immediately use them to send frequently and broadly, so ideally you want to start with a small list that you email a few times a month. Then, add volume over time.

As you send more emails to more people, there’s more data to associate with your reputation. Subscribers who open your newsletter, click links (that aren’t unsubscribe links!), and reply or forward emails show their mailbox provider that your content is welcome and trusted. For better and for worse, altering the cadence of those emails affects how people engage with them.

Sending too frequently

Imagine you’ve been receiving a weekly newsletter for a year and are loving it. Suddenly, it switches to a daily format. Even if you still love the content, you likely don’t have the bandwidth. So you stop opening every issue, reply less frequently, and click on fewer links. You might even see people posting online about unsubscribing or even marking it as spam. 

Based on what we see from Buttondown users who send more than once a week, Gmail is rate-limiting frequent senders by default. Other mailbox providers send daily newsletters to spam. And, as unfair as it might seem, a newsletter might also get dinged for doing the exact opposite.

Sending too infrequently

Similar to transitioning from weekly to daily, dropping from monthly to quarterly may stray too far from subscribers’ original expectations. They might forget signing up for the newsletter in the first place or what it’s about, again opening fewer emails, clicking fewer links, and eventually unsubscribing or marking newsletter issues as spam. 

Worse yet, even in the face of neutral engagement metrics, sending less often can be interpreted as a less active, less influential relationship. Or it may be that ESPs and mailbox providers simply don’t feel like they have enough data on an infrequent sender to trust them. Again, this shouldn’t impact newsletters with small, engaged lists. For others, it’s important to make gradual changes to avoid subscriber shock.

Sending predictably and consistently helps deliverability

From a purely data-driven perspective, a sudden switch from quarterly to daily, or vice versa, doesn’t “look normal.” It looks like a compromised or abandoned account, like one that isn’t respectful of subscribers’ inboxes. 

At the risk of oversimplifying things, maintaining consistency is often more important than some arbitrary frequency that worked well for someone else. Sending daily is fine, as long as you start with a small list, have new subscribers double opt-in, and grow at a reasonable rate. A quarterly newsletter is also not a dealbreaker, for small lists with good engagement. As it grows, however, you might want to introduce short updates or roundups as a way to send more often without overburdening yourself.

A reputation system built entirely on numbers is pretty heartless, obviously. A sender or subscriber’s habits can be sidelined by unexpected life events. Even Google’s documentation tries to play down the impact of “engagement-based filtering.” But it’s a product of the Faustian bargain that we made to (mostly) get rid of spam. And if you can get into a rhythm, sending at predictable intervals that your subscribers appreciate, your newsletter will have a much better chance at staying out of spam folders.

How to settle on your newsletter’s cadence

Other than having a supernatural awareness of your own output and your subscribers’ preferences, months into the future, there are a few ways to figure out the best frequency for your newsletter. Some are technical, others are aesthetic. Arguably all that matters, though, is figuring out what your readers want.

Based on wordcount

Longer emails take longer to absorb and sink in than shortform newsletters. Pulitzer-winning science journalist Ed Yong’s newsletter, for example, usually clocks in at least 1,000 words (with dozens of gorgeous birding photos in every issue!). For him, an issue every other month makes sense. Cassidy Williams’s newsletter is shorter and more templated, between 300 and 400 words with bullet lists of interesting links. It’s easier for her to get issues out every Monday. And for subscribers to open them, skim for links they like, and send positive engagement signals in short timeframes. In the absence of data, your writing style is the best way to choose your newsletter’s cadence.

Based on data

For more black-and-white guidance, email open tracking and click tracking can measure subscriber engagement in response to frequency changes. Open and click tracking aren’t especially accurate, as mailbox providers like Gmail and Apple supply fake data to pixel trackers. But they can establish relative trends that inform how increasing or decreasing cadence affects engagement. You might create two list segments with tags and see how each reacts to different schedules, as an A/B test. 

Based on user input

There is, of course, the simpler, more overt approach of…just asking people what they want. You could add a survey to your newsletter and then decide by committee how often to send. Or, if you have a weekly email and a handful of people indicate they want monthly emails, add another newsletter to your account for monthly emails (which, on Buttondown at least, is free if your total number of subscribers stays the same). 

Be careful not to overemphasize newsletter cadence as a deliverability variable, however. Tools like Postmark's spam score checker, MXToolbox, and Google Postmaster Tools can help you figure out whether it’s volume or frequency that’s causing an issue, or something else.

It can also help to clean your list often and remind people to update their account preferences in the subscriber portal, if your newsletter platform offers one. And when optimization and data fatigue begin to creep in, remember that Infrequent emails with high engagement beat frequent emails with low engagement. So in some cases, slowing things down for your own sanity might actually improve performance, as long as you plan ahead.

How to change your newsletter’s cadence without hurting deliverability

Graduated transitions are what you want when moving to a new publishing schedule. You wouldn’t want to go straight from a weekly newsletter to an every-other-month cadence without warning. That wouldn’t look good to ESPs or to subscribers. Instead, you’d want to announce the change to your list and, ideally, ease into it over time. A couple of months of sending every other week, followed by two or three monthly sends, then settling into the new schedule, would give you time to see how it affects performance. If the numbers don’t look good, or if one of the in-between cadences feels better than you anticipated, give it more time. 

As a rule of thumb, try not to increase your sending frequency by more than 2x in a single month. If you're going from monthly to weekly, for example, spend a month or two at twice-monthly first. This gives ESPs time to adjust to your new pattern and prevents sudden spikes that can trigger rate limiting or spam filters.

Shifting into a higher gear is usually much trickier. Say you’re gearing up for a product or book launch and want to move from a monthly to a weekly schedule, for example. Jumping straight in would be a 4x increase, bumping right up against Gmail’s rate-limiting threshold. Beyond adding a buffer period of twice-monthly sending, you might want to segment your list into smaller groups to avoid hitting your entire list with every send. And, assuming it’s a seasonal or promotional schedule, tell subscribers in advance when it will begin and end. Then, provide a link for them to opt out of seasonal or promotional emails by joining a list segment that won’t receive them.

Whether you’re ramping up sending after a newsletter hiatus or pumping the brakes, data and subscriber replies are your friends. They’ll provide early warning signs so you can make adjustments to your transition plan and prevent broader engagement issues from snowballing into deliverability issues. Alternatively, you could hack your way to a more frequent sending.

What to do after a massive windfall of signups

If your newsletter goes viral or you get featured somewhere that drives thousands of new subscribers overnight, resist the urge to immediately send to everyone. A sudden spike in both list size and sending volume can look suspicious to ESPs, especially if those new subscribers haven't had time to engage with your content yet.

Instead, maintain your existing cadence for the first few sends. This gives new subscribers time to confirm their subscription (if you're using double opt-in) and start engaging with your content. You might also consider segmenting your list so that new subscribers receive a welcome sequence first, while existing subscribers continue getting your regular newsletter. This spreads out the sending volume and helps establish positive engagement patterns with your new audience before you increase frequency.

If you do want to increase cadence after a spike, wait at least a month and make sure your engagement metrics (opens, clicks, replies) are holding steady or improving. Then follow the gradual transition approach outlined above—no more than doubling your frequency in a given month.

How to up your cadence when you don’t have the time

There are oh so many ways to send more newsletters without overcommitting on writing time. Some aren’t all that sexy, representing more of a creative reorganization of your current output than a substantive change:

• Draft several issues in one sitting, to take advantage of writing momentum and build up a backlog. 
• Chunk longform writing into shorter wordcounts, like turning monthly deep dives into weekly chapters of a larger narrative
• Repurpose or revisit older issues by adding updates and retrospectives.

Other approaches let you increase the total volume of what you’re sending, with only marginally more writing, and (importantly) without feeding your subscribers a bunch of uninteresting filler content:

• Create community-powered emails by turning user-generated content (newsletter replies, Discord conversations, social media mentions, etc.) into issues that you can throw together and send between issues.
• Send unstructured or stream-of-consciousness reports about whatever you’re currently working on, giving your most dedicated fans a look behind the scenes.
• Curate lists of links and snippets from what other people have been creating and writing about that’s adjacent to what you’re working on.
• Set up newsletter automations to create multi-email welcome sequences and "drip" campaigns that send out semi-templated content at pre-determined intervals (which, yes, count towards your sending frequency).

These in-betweeners help sustain engagement when there are long gaps between “normal” issues, without asking too much of your subscribers. You can send them to a subset of your most engaged subscribers and avoid overwhelming more casual readers, giving ESPs and mailbox providers a slew of positive data points to chew on. 

Don’t send often just because it’s a “best practice”

If you send at least weekly, or have several thousand subscribers, consider putting more time between issues. If that’s not possible, warm up your newsletter by at least starting slow and segmenting your list so you’re not blasting everyone with every email. Don’t cram too much content in daily or weekly emails and let people join different lists based on their preferred cadence. For smaller teams and solo writers struggling to hit an “ideal” sending frequency, try low-key updates and roundups in between your most important emails. 

Regardless of your list’s size, always try to make slow gradual changes to sending frequency, while keeping an eye on engagement and deliverability data. That will help you keep tabs on the less-human side of deliverability.

Any two-way communication is as much about silence as it is about noise. Listening, absorbing, and contemplating are essential to emails that people want to read, unlike social media, where restraint and composure get buried by algorithms. Sure, the gatekeepers of spam may not understand infrequent or irregular (see: human) sending cadence. But subscribers always have the final word.

When people adore your writing they will seek it out. And if they find it in the spam folder, you won’t be there for long.