Hi there, I am co-founder of Hookdoo (https://www.hookdoo.com/). It's an SaaS that lets you execute shell scripts on your server(s) on incoming webhooks.
I am also author of an open source webhook server (https://github.com/adnanh/webhook) that pretty much does the same thing, and it sort of got popular.
Most of the traffic that goes to Hookdoo, comes from the webhook's github readme. I have also went around on Q&A sites such as stackoverflow, digital ocean community pages, etc. and answered appropriate questions with how Hookdoo could help them, and we have seen few trials coming from there which converted to paying customers.
One more thing I did was write Medium blog post on solving a particular issue (automatic deployment on github push) using Hookdoo, which generated a lot more of trials that converted into paying customers.
What else could I try to get more users?
How do I spread the word out?
You can try submitting it here https://founderkit.com/
Have you given any thought to who your customers are? Ideally, you would have been talking to potential customers while building your product to develop a sense of who they are. If you know your customers, reaching out to them becomes easier. Or, at the very least, you'll know where to find them. Please note that simply stating "my customers are developers" does not cut it ;)
Start by talking to the users you already have. Develop a simple interview script with a small amount of questions. Make sure these questions give you insight in who your customers are and why they choose to use your product (try to not make the questions about your product). Put down the answers into a Google doc and start looking to general themes amongst your customers.
Once you have a better idea of who your customers are, you start exploring marketing channels. At that point, you might want to have a look at Gabriel Weinberg's book Traction, which does an amazing job helping you explore different traction channels for your business.
Good luck!
You can also try Quora, Reddit and Hacker News (I think the last one will be best for you).
With such a specific product I will advise you to start writing catchy blog posts about tech and try to get traffic to that.
Thanks for the input!
Already did some subreddits and show HNs. Oddly enough, hackernews visits didn't convert as much, even though I thought it would be the best match :-)
I did not try Quora just yet, but I most definitely agree about the blog posts. With the Medium's SEO, it's amazing how much traffic you get basically for free, so I won't be giving up on those for sure.