Essential questions when evaluating a web design agency include: What's your design and development process? How do you handle revisions and feedback? What CMS platforms do you specialize in? Can you share case studies with measurable results? How do you approach SEO and conversion optimization? What's included in post-launch support? How do you handle project timelines and scope changes? Who will be working on our project? How do you ensure the website reflects our brand? What's your approach to responsive and accessible design? These questions help you assess both capability and compatibility.