There are many ways to make money online nowadays whether you're a front-end or back-end developer.
create tutorials and publish them on YouTube and make money from when you get 1000 views per video through ads. This is a fully passive income no maintenance needed; however, it takes times and effort to make a good series of tutorials videos. Alternatively, publish your tutorials on sites such as udemy.com
Create a blog, create a unique template or buy one on templatemonster, be specific to one niche in this case focus on a programming language that you know quite well, start writing quality articles and share them everywhere. Once you get 100 unique visitors per day, you'll start making money with Google AdSense and Amazon affiliate marketing
Create a fully functional website from scratch, buy a domain name build it with a content management system like WordPress or if you want to build something more unique, large scale and secure with Umbraco, add content get decent traffic and sell it on flippa
build an e-commerce website and sell a few products related to your web development niche, find your specific niche, create a domain/brand name with your own logo. Buy product on Alibaba (you'll find the biggest Chinese manufacturers) customize them with your logo, list them on your e-commerce site and on Amazon FBA.