What a successful SaaS uses to run its business in 2025

Note that some links may be affiliate links, and kudos to Cushion for the inspiration behind this page. (All costs are monthly; I list one-time purchases as having an ongoing cost of "$0".)

(Interested in the open source software we use and maintain? Check out the open-source software page.)

FAQs

Why do you use so many services?

The most important resource I have is my energy, and being able to trade X dollars (where X is any number less than a hundred) for even trivial amounts of energy is an absolute no-brainer.

Why so many ESPs?

When I launched Buttondown, AWS Simple Email Service was notoriously low-quality and Postmark did not support broadcast emails. Mailgun was the choice I went with, and there are still many customers using Mailgun’s rails who have custom domain records set up that I don’t have the heart (or incentive) to migrate.

I like having redundancy — if one provider were to go down or drastically change rates it would be trivial for me to migrate — but if I were starting Buttondown from scratch I would likely just have everything run through Postmark.

Why don't you use something for X?

Some specific choices I made to roll my own:

• Auth: I know it's increasingly trendy to outsource auth to a paid vendor but I'm not a fan of the lock-in and I like having full control over the experience.
• Feature flags: rolled my own for performance reasons. Plan on open sourcing it at some point.

Changelog