I've tried two approaches:

1. Integrate with Intercom. It requires syncing your database of users and any data/events that's relevant for the emails you send. So the downside are that it requires a bit of setup, isn't as flexible as a custom-made solution, and costs money. The upside is that it's super easy to write and send emails which is something most of us probably don't do enough of yet.

2. Add these one-off emails to my codebase. This is a bit of a hassle as it requires re-deploying the app if you want to send an email. It also is prone to error with sending to the wrong people or sending duplicate emails. You'll need to manage unsubscribes, etc. The upside is that it's not yet another monthly bill, and it's really flexible. You can target just the users you want quite easily and have access to all the necessary user data without needing to share it with a third party.

I'm not sure which one I prefer.

Another downside of Intercom is that their unsubscribe logic is basic, so if users unsubscribe from onboarding campaigns - then I think they will not receive broadcast emails.

While building MoonlightWork.com, we built an email digest that auto-sent every week. It read from different feeds - including a headwayapp.co feed, our blog, some internal APIs, and a "custom intro" feed. So, any announcements we included in that weekly email. It worked super well.

I do like HeadwayApp.co, but they don't handle email subscriptions. Perhaps there's an opportunity for a product like that, but with subscriptions?

For #postcard I'm just subscribing everybody to a postcard at updates.postcard.page. My goal is to build personal websites for people, but it's conceivable to update the product for an api-driven updates mailing list. If you're interested in this, I could definitely experiment with it.

We have a few products and mailing lists so we have our own install of Sendy running.

Each product gets at least 2 lists. One for marketing and one for users (ie, a required message).

We add/remove users to lists via API integrations within the apps themselves.

May not be useful if you only care about 1 product but Sendy is so cheap, and I run it on a $5/mo VPS. Plus SES costs, It's been fine for us so far and very cheap.

But how do you deal with one-off broadcasts like announcing a new product feature?

My advice is that if it feels like a newsletter, I would probably treat it like a newsletter and use Sendy or one of the pay-per-blast services. That way, people can unsubscribe without your servers getting a reputation hit because someone can't be bothered to click the unsubscribe link. Once you get flagged by Google's mail servers, you can never fully get it back.

I switched off of Mailchimp after many good years of service because they changed how their "constantly-changing-noun-for-groups" worked, and our $30/month plan was going to be $199/month or $299/month. This made zero sense for a list of 3k to 5k people.

For basic sending, I'm currently using Mailgun for my projects and it uneventfully just works.

For Chocolab I used sendinblue, activecampaign ect but this was for regular newsletters to 50k subscribers.

For smaller stuff and much cheaper, I've been enjoying using Mailguns API to create mailing lists and then you just send an email to an address and it sends to the mailing list. Very good for just plain text updates and very cheap.

I use Intercom for general announcements like product updates, as I don't think the importance of using Mailchimp if Intercom gives me the same ability.

We created an email model in our platform and added an ActionText (trix) field to it so you can add images, we track Clicks and unsubscribes using Ahoy Email gem.