Web design is the visible, customer-facing part of the website. A web designer focuses on what your website looks like and how visitors will interact with it. Good web designers use proven professional design principles to create a great-looking website. They also understand usability requirements and know how to create a website that customers can easily navigate and use to find the information they need.
Web development is the back-end implementation of the website, the programming, and interactions on the pages. A web developer focuses on how your website works and the tasks that visitors need to accomplish. Professional web developers have expertise in a number of programming languages and approaches. They know how to determine which implementation methods are best for your project and needs and the keys to keeping a website running effectively and efficiently. They understand how to structure the website so that changes can be integrated later without compromising functionality and performance. They know how to implement back-end capabilities such as slideshows, forms, and online payment.
For many smaller organizations, it makes sense to find one resource to handle both design and development.
Some designers know a fair amount about programming. And many programmers understand the principles of design and usability. Some amount of overlap is critical to getting the best possible result from those in either profession. In your search, if you want to work with only one person, you need to ask the right questions and know what candidates are capable of providing.
Many organizations can’t (or don’t want to) hire both a web designer and a web developer to get the job done. They want one resource who will take them through the entire process, start to finish. Dealing with two phases, plus the handoff between two contractors, is more than many organizations are willing to handle.
If you hire two different resources (people or organizations) to get both jobs done, you need to understand the difference between their responsibilities and orchestrate the handoff and communication process—and that may be more overhead than is necessary.
When it comes to hiring a single resource, it might be one person or one business that includes multiple employees to handle the different parts of the process. What I do not recommend is hiring one person to do the design work and then handing that finished design to a completely independent resource who was not part of the design process. You want a single resource, and if there will be communication or handoff issues, at least a company will have that built into their internal process so you don’t have to deal with it.