Previously:

  https://news.ycombinator.com/item?id=11522661
  https://news.ycombinator.com/item?id=11519085

  While Heroku charges a small premium over other hosting services

The "small premium" is not small at all.

The amount they're spending on heroku is relatively low compared to the cost of the 150TB of bandwidth their using from imgix.

I guess that's the next point then, if you're spending that much on traffic you should probably look at just buying dedicated bandwidth.

I'm sure it doesn't have the same awesome CDN latency and I'm also sure it doesn't matter one bit for multi megabyte images.

When I've spoken to folks running infrastructure, for a lot of companies straightforward advice such as this always worked to cut costs: Move from Heroku/whatever other managed provider for your actual database/worker/webserver as costs will rise as you scale Start using AWS Reserved Instances and Spot Instances (or similar) for your workloads

Advice such as this has often saved > 30k/month hosting. The caveat is these were mostly SaaS companies dealing with data.

Interestingly enough in Unspash's case, their actual cost on Heroku/etc is fairly minimal as they don't seem to be doing much with the data. If they start building things that collect a lot more user data, run ads, do lots of stuff with it transforming user data, run analytics, etc., their heroku infrastructure will be a bottleneck. Right now, it's not.

How do they generate profit?

They have 3-5 feeder sites as free services that bring them traffic for crew.co. That's where they presumably make enough money to finance Unsplash, their office/café/etc.

well i still think it's a lot of money to run a site like this!

As a referral source for new business in your marketing budget it would be a very good investment even if it only generated $150000 a month in new business. And I have no doubt they are getting a heck of a lot more from it than that.