Fly.io: The reclaimer of Heroku's magic

The only thing I don't like is their usage-based pricing. On Heroku I could pay $7 a month and know I'd never be charged more than that. I'm sure when you're scaling a service it's fine - maybe even better - to do it on a sliding scale. But for a fire-and-forget blog site, I don't want to have to worry about stuff like that.

This is a problem. And a bit of an own goal on our part.

I hate services that don't put a price on things like bandwidth (because there's always a price!). So we priced bandwidth and made it transparent. You can put an app on Fly.io and server petabytes of data every month, if you want. We'll never complain that you're serving the wrong content type.

But the reality is – having an unlimited bandwidth promise is perfect for for a fire and forget blog site. We're not doing ourselves any favors with scary pricing for that kind of app.

I don’t want an unlimited bandwidth promise, I want a cap that I know can never be exceeded. I mean, I use Azure professionally and one of the key reasons I don’t use it to host my own stuff is exactly because it could potentially become very expensive. I’d rather have my own stuff shut down until I decide what I want to do with it.

Things like alerts are fine, professionally, but not for things like running a small app, blog or whatever, that you’re not sure where is heading.

I don’t think anything I’ve build on my own time has ever ended up breaking my bank, but signing up my credit card is a risk I’m never going to take, and I’m fairly certain I’m not alone in that. Of course I have no idea if there are enough of us to make small scale fixed prices products profitable at scale.

We actually launched with that feature: https://news.ycombinator.com/item?id=22616857

No one took us up on it. What we found is that the majority of people want their stuff to stay up, and the right UX for "shut it down so you don't get billed" is not obvious.

We ended up implementing prepayment instead. If you sign up and buy $25 in credit, we'll just suspend your apps when the credit runs out.

Bandwidth is weird because we have to pay for it (as does every other provider). We aren't yet in a position where we can just make it free without limits. Maybe next year. :)

I'm actually very curious: why is bandwidth so much cheaper on more traditional VPS or dedicated server hosts like Hetzner ? This extends to their somewhat new-ish cloud product, where you get 20TB traffic included - even on a tiny instance. And it's 1 Euro per TB after that. [1]

Do they just decide to not profit from bandwidth or are they doing something special that allows them to be so cheap?

[1] https://docs.hetzner.com/robot/general/traffic/

There are three ways to manage bandwidth prices:

1. Put servers where bandwidth is cheap (not Sydney, for example)

2. Constrain throughput per server

3. Buy from cheap transit providers like Cogent

Hetzner does all three. Bandwidth in the US/EU is very cheap. They meter total throughput on their services. And they use cheap providers. None of these are bad choices, just different than ours.

Our product has multiple layers, too. When you connect to a Fly app, you hit our edge, then traffic goes to a VM that's probably in another region. When you hit a hetzner server, there are no intermediate hops.

We usually pay that three times as data moves from customer VMs to our edges to end users (out from our edge to worker vm, out from worker vm to our edge, out from our edge to end user). Or 10x, in some cases, if data moves from Virginia to Chennai to an end user.

We pay $0.005/GB in the US and $0.9/GB in Chennai. You can see how this might add up. :)