As a software engineer, there are several ways you can make money through side jobs. Here are a few options you can consider:
Freelancing
Offer your services as a freelance software engineer. Websites like Upwork, Freelancer, and Toptal provide platforms for freelancers to find projects and clients. You can work on projects ranging from web development to mobile app development, depending on your expertise.
Personal thought: make sure that your freelance should not conflict what you are working on. For example, if you work for AWS and you receive a freelancing job from MS, it won't work.
Develop and sell software products
Identify a problem or a niche market and create software products to address those needs. You can develop mobile apps, web applications, plugins, or even create software tools that help automate certain tasks. Market and sell these products through platforms like app stores, software marketplaces, or your own website.
Personal thought: if you can make well-made and monetize it properly, you can be free from your ordinary job as well!
Create online courses or tutorials
Leverage your expertise as a software engineer to create educational content. You can create online courses, video tutorials, or written guides on platforms like Udemy, Teachable, or your own website. This allows you to earn money from course sales or through subscriptions.
Personal thought: same as above. It could be your another permanent source of income.
Consulting
Provide consulting services to individuals or businesses that require your expertise. This can involve assisting with technical challenges, advising on software architecture, or conducting code reviews. Network within your professional community or leverage platforms like LinkedIn to find consulting opportunities.
Personal thought: If you are not good at communication with your clients, you will be hard to deal with it. However, if you are used to contribute to customer's problem effectively by consultation, you will be rich as well.
Open-source contributions
Contribute to open-source projects in your spare time. This not only allows you to improve your skills but also helps you gain visibility within the software development community. Some companies sponsor open-source projects and may offer paid opportunities for contributors.
Personal thought: this is something we can enjoy the work and make money as well if you are interested in open source.
Remote work
Explore remote work opportunities that allow you to work on software projects during your free time. Websites like Remote OK, We Work Remotely, and Stack Overflow Jobs often list remote job openings for software engineers.
Personal thought: Be cautious. Too many remote work will ruin your personal life as well.
Remember to consider your time management and ensure that any side job you take on doesn't conflict with your primary employment or violate any contractual agreements you have.