Stripe

Stripe is the payment processor most newsletter platforms plug into when they offer paid subscriptions — Ghost, Kit, and plenty of custom setups all use it under the hood. If you're running your own site rather than relying on a platform's built-in payments, Stripe is generally what you'd wire up yourself.

What makes it the default choice is the combination of solid developer tooling and support for recurring billing, which is exactly the shape of a paid newsletter subscription. It also handles the messier parts — failed card retries, tax collection across regions, subscriber-facing billing portals — that would otherwise be a lot of work to build from scratch.