Comment by vectorfrog

I built it after one of my clients complained about not wanting to accept files via SFTP because they were an Azure shop, and Azure charged over $200 a month for an SFTP endpoint even if you only upload a single file a month. I didn't believe them at first. After all, I'm old enough to remember the days when every web developer had FileZilla on their computer because FTP was how we updated the HTML files for websites. I mean, a technology that was included in every $3/month Bluehost account couldn't possibly be that expensive. Then I checked it out, and not only was he right, but AWS's SFTP service (Transfer Family) was the same price.

My mind was blown, and then I thought, I bet Erlang has a library that handles SFTP, which means I could set something up using Elixir pretty easily. Sure enough, Erlang always seems to deliver (this time it was :ssh_sftpd). I was able to get an Elixir solution up and running pretty quickly. The client actually ended up not needing it, but setting up that SFTP server had lit up my imagination about what was possible with Elixir.

The theory behind why SFTP services are so expensive is the likelihood of getting hammered by cron jobs logging in to sweep content directories. I'm not sure how much of a reality that is, but with Elixir managing the SFTP I was able to set up limits on how often an IP can log in to a directory. I also set up webhooks for users that really did have a need to get new files as soon as they arrive.

The problem with Elixir is that Phoenix makes it too easy to set up realtime channels, so as soon as I got the SFTP server up I thought, "ooh, I could also have a web UI that would automatically update showing the files in the directory without needing a page refresh." So I did. Then with a web UI showing the directories and the files in there, I realized that people would expect a way to upload and download files from the UI. And just like that, my SFTP server turned into a file share as well.

I've been using the file sharing for several months with my clients, and it's actually been really handy for transferring files that didn't really belong in a code repo.

Since I've been using it for myself, I had it on its own domain while I've been going through my wishlist of what I thought the MVP needed to include. I wasn't really in any rush to ship, but that changed a couple weeks ago when I got not one but two paying customers seemingly out of the blue. I reached out to one of them and it turns out that ChatGPT had been recommending my solution as the "most affordable" SFTP option.

That user had signed up on the free tier about a week earlier. I only found out he was using the product because I had decided that before I launch I should replace the free tier with a lifetime deal. At this point, I didn't think anyone other than me was using the site, so when he logged in the next day, he hit a paywall! I would have absolutely have handled that differently had I realized that someone was already using the solution. Thankfully, he is incredibly kind and just bought the lifetime deal instead of complaining about how I just rug-pulled him! I asked if I could set up a phone call and find out how he's been using the product. He was super gracious, told me he'd been using the SFTP to get product information from his suppliers and that everything had been working great so far, and was even kind enough to provide a testimonial.

Setting all of this up has been a treat. This was my first Elixir project since AI tools have come into their own from a development perspective, and I've been pretty blown away with how well Elixir projects work with AI. The majority of my headaches have come from trying to set up zero-downtime code releases now that I have users. I was thinking that Elixir would have this pretty well ironed out, but in truth, it's been more about setting up the deployment to run multiple Docker instances and allow connections to "drain" from the old instance. While this works, I'm pretty sure this could be done with any framework; it's not an Elixir thing. That's been my only disappointment with Elixir during all of this. I'd read about Elixir's hot code reloading and thought one day I'd set it up. But it sounds like even the Elixir community has abandoned this in favor of smart Docker management instead.