The gist VS Mailtrain

Graphile worker has been great for me because it's a library that works with Postgres that allows me to queue jobs and execute them on the server without adding too many additional layers of complexity for being able to accomplish async tasks. (I'm aware of how popular bull is, but I don't want to add another data-store only for async tasks)

Bull is currently in maintenance mode, we are only fixing bugs. For new features check BullMQ, a modern rewritten implementation in Typescript. You are still very welcome to use Bull if it suits your needs, which is a safe, battle-tested library.

I use bullmq with node

You might consider using a queue for processing the request. I've found bullMQ, which works with Redis, to be a nice developer experience.

BullMQ is a pretty solid choice: https://github.com/taskforcesh/bullmq It's the successor of Bull: https://github.com/OptimalBits/bull

BullMQ

For Node.JS you can use something like BullMQ (https://github.com/taskforcesh/bullmq) and then dispatch jobs to the message queue with your worker handling the jobs. You can read about an example for Bull MQ here (https://deadsimplechat.com/blog/best-nodejs-schedulers/#2-bull)

bullmq seems like an open issue

In order to try and mitigate the OOMs. I read the Background Jobs in Node.JS with Redis blog post and implemented Heroku Data For Redis with ioredis, BullMQ and Throng,

I have used mailtrain for a while to send out a small newsletter with articles from an rss feed, but mailtrain does not see much development anymore.

In many cases an email group could be defined a simply as a forwarder with multiple recipients configured for it. For more complexity, I really like this: https://github.com/Mailtrain-org/mailtrain

Mailtrain documentation is lacking big time