What's great
Switched to Resend for Signum's transactional emails after getting burned by another provider's deliverability. Setup took maybe 30 minutes including DNS verification. Using it for watchlist alerts — when a domain a user is tracking changes risk score they get an email. Works reliably, the logs actually show you what happened to each email which sounds basic but wasn't always the case with what I used before.
What needs improvement
Would love more examples for Python/FastAPI specifically, most of the docs lean toward JS. Had to figure out a few things by trial and error.
vs Alternatives
Transactional emails for Signum — watchlist alerts, welcome emails, weekly digest. Needed something with clean API and reliable deliverability.
What's great
Stripe is one of those tools where the docs are so good it almost feels like cheating. Set up the full checkout + webhook flow for Signum in an afternoon — user upgrades, webhook hits the backend, plan updates in Supabase, done. The test mode is underrated, simulating failed payments and edge cases before going live saved me from some embarrassing bugs in production.
What needs improvement
The webhook signature verification docs could be clearer for Python specifically. Took a bit of trial and error to get it right with FastAPI.
vs Alternatives
Handling payments and plan upgrades for Signum's Pro and API subscriptions. Needed webhooks that play nicely with FastAPI and Supabase.