Eliminate a Significant Pain Point of the Customer To outperform the competition your startup has to solve a serious customer problem. You have to create a solution that users will need to have not nice to have. For a product to be successful it has to serve a purpose and be unique many successful startups are often built on novelty and distinctness.
If you are trying to come up with good startup ideas for web developers then think about how these ideas can help users and what problems they solve. If your product has an outstanding purpose that will help people in some mobile app development service area then it will be successful. Useful products help users save time and simplify frequently used processes.
You have to determine how your product will help users what specific issue it will solve and whether it can fill a particular gap in the market. Remember that if you don't take user issues into account you can't successfully build a startup idea. If your startup is analogous to certain popular products on the market and you are confident that it can solve a user problem more effectively.