How we keep deliverability high

TL;DR

Everything we do comes down to three things:

Make sure the only people getting your newsletter are the ones who actually want to get your newsletter.
Make sure the emails being sent out are content-rich, accessible, and performant.
Be deliberate and careful in who we allow onto the platform to make sure our reputation stays golden.

There's no secret sauce — it's not rocket science. It's just diligence and good engineering. But for the details, keep reading!

Mandatory double opt-in

Some email platforms treat double opt-in as a "table stakes" feature that authors can turn on and off as they wish, or even treat cold emailing (the practice of sending emails in bulk to addresses who haven't given you permission to do so) as legitimate.

Buttondown... does not. Every single subscriber on Buttondown must explicitly opt into your newsletter. This keeps the risk of spam complaints low, your engagement high, and readers everywhere happy.

That being said, we're nothing if not flexible and hospitable to other use cases. If you're confirming double opt-in outside of Buttondown (for instance, asking authors to confirm their interest as part of a registration or checkout flow) you can always email us and we can discuss other options!

Automatic clean-up

Even if a subscriber to your newsletter is a real human who explicitly signed up to hear more from you, you might not want to keep them around if they haven't opened a single email from you in months. This is referred to as a number of different things across the industry ("list cleaning", "email scrubbing", "email hygiene"...) — we call it subscriber cleanup. It's an automatic opt-in process that checks for folks who are suspected to have abandoned their email address or have never engaged with your content. Removing these folks from your list might feel a bit like ripping off a band-aid (it can be sad to see the big subscriber count go down!) but is great for the long-term health of your subscriber base, because it means your engagement rate amongst your true fans will be higher.

(You can read more about subscriber clean-up here!)

A human eye

Last but not least, every single new Buttondown newsletter who imports subscribers from an external source goes through a manual approval process to make sure everything looks kosher. This is old-school, we know, but it's for the safety of you and every other author on the platform. We take our sending reputation and deliverability seriously, and this helps us maintain our best-in-class benchmarks on both fronts.

(If you're worried that this process is Kafka-esque and will take days on end, worry not — we generally complete it in less than eight hours during the week and less than 24 hours during the weekend.)

Offboarding people who don't pass our bar

A human eye is great, but it's not perfect, and circumstances can change — maybe an author starts abusing their API privileges or decides to otherwise violate Buttondown's terms of service by sending emails to folks who haven't signed up for them.

If you're found to have breached our internal threshold for either the number of emails you send that bounce or the number of emails you send that are marked as spam, we'll reach out to talk about your sending strategy. If those conversations don't go anywhere, you'll be removed from the platform.

(Sometimes, when we mention this, we're greeted with a bit of shock and dismay — "so you'll remove me just for sending more emails than usual?!" Buttondown's never off-boarded a well-meaning customer who made a mistake double-sending an email or accidentally imported bad subscribers; it's only ever been malicious actors.)

Pre-flight checks

Before sending your email, Buttondown runs a battery of 62 pre-flight verifications to make sure everything's in ship-shape. We check everything you can think of, like:

Do you have specific words or phrases that Gmail or other inboxes will flag as spammy?
Are any of your images too large?
Did you use the word "attached" without actually attaching a file?
Did you add too many images, meaning that some clients will refuse to load or send your email?

This validation suite makes sure you're sending out the best possible email, and the best possible email gets delivered at the best possible rate.

IP-based subscriber filtering

Buttondown works very hard to make sure all of the subscribers joining your newsletter are legitimate, so that they're not giving your publication a bad reputation. One of the first and most effective lines of defense is checking incoming subscriptions' IP addresses against a combination of both our internal datasets and those of trusted vendors like Spamhaus and Project Honeypot. (Note that we do this by pulling in omnibus data from external sources, rather than polling them, so as to protect the privacy of you and your subscribers.) This lets us immediately filter out automated or malicious bots subscribing to your newsletter.

No in-app cross-promo

One of the bigger product decisions Buttondown has made is to not push cross-promotion — this is the fancy industry term for "when someone subscribes to your newsletter, we suggest three similar newsletters for them to also subscribe to."

There are a number of reasons we do this — mostly, we don't think it's our place to get in between you and your audience — but the biggest one is it hurts everyone's deliverability. Studies that Buttondown's run show that subscribers who sign up for other newsletters through cross-promotion end up reporting emails as spam and unsubscribing at a much higher rate — even for the newsletter that they originally signed up for!

Other platforms tout growth through cross-promotion to juice your subscriber base; while you're of course free to run your own manual promotional efforts, it's not worth the risk to deliverability for us to push them on your behalf.

SPF and DKIM

You don't really need to know what these clumsy-sounding acronyms are, but they're protocols that we (along with many other reputable senders) use to ensure that the emails we send are coming from us, not someone pretending to be us.

Setting up SPF and DKIM are a bit of a hassle to handle yourself, but if you're sending from Buttondown it's automatically handled for you (even if you're sending from a custom domain!) And starting in 2024, Google requires all senders to send their emails with these authentication protocols in place.

We keep it easy for subscribers to unsubscribe

I'm sure this has happened to you:

You bought something online.
You started getting an email every. single. day. from the retailer.
You finally got fed up and hit unsubscribe, except that page took you to another page which took you to another page.
And then you still got an email the next day, because you unsubscribed from "weekly recommendations" but not "hot deals" or whatever.

Yeah — that drives us crazy too. Every email coming from Buttondown is one-click unsubscribe compliant, meaning that there's no labyrinthine set of hoops to jump through to unsubscribe. You might not love this as an author, but it's good for you in the long run — unhappy subscribers turn into frustrated subscribers, frustrated subscribers report your newsletter as spammy, and spam reports tank deliverability.

Emphasis on text over images

Buttondown's default email templates are very plain-text forward. This is nice for aesthetic reasons, but also is very positive on deliverability. Text-heavy, less rococo emails (as compared to their image-heavy counterparts) work great on inboxes of all sizes and shapes and score extremely well in content scanning, meaning that you'll be reaching more of your subscribers more reliably.

Bring your own domain

Last but not least, Buttondown lets you send from own domain (if you own one!) This improves the overall engagement rate for your emails, as they appear more personal and have a higher domain reputation. More importantly, that domain reputation carries with you — even if you leave Buttondown for another service, so long as that service also allows you to send from a custom domain.