Core specializations of web design companies in Chennai encompass: 

• UI/UX design 
• Front-end development 
• Back-end development and server-side scripting 
• Search engine optimization (SEO) 
• Responsive design 
• Content management system (CMS) integration 
• Database design 
• Website security 
• Quality assurance and cross-browser testing 

A typical web design project for a standard business website generally takes anywhere from 4 to 12 weeks. Simple, template-based websites can be completed in as little as 2-4 weeks, while multi-site, custom eCommerce platforms or web applications often require 3 to 6 months or more due to extensive development and testing.  

Ultimately, the total duration will depend on the site's complexity, number of features, revision rounds, and the client's speed in providing content and feedback. 

Web design agency’s pricing is primarily determined by the scope and complexity of the request, with custom designs, advanced functionalities, and third-party integrations requiring larger budgets. Other factors include the agency's reputation, experience, location, as well as whether the client requires additional services, such as content creation, maintenance, SEO services, etc.  

To verify a Chennai web design agency's credentials, you should review its portfolio to assess the quality and diversity of their past work, with emphasis on live websites and case studies. You should also look for client testimonials, reviews on independent platforms like DesignRush, and industry certifications or awards that validate their expertise.  

As a bonus step, you could check the agency's "About Us" page and staff profiles on LinkedIn to verify the team's experience, tenure in the market, and technical skills. 

Web design companies in Chennai typically handle project revisions by including a pre-defined number of revisions at specific project milestones, i.e., after the initial design mock-up or the first development build.  

They usually outline these limits and the associated costs for any out-of-scope changes in the initial contract to make sure the project remains on track and within budget. For efficiency, feedback is often collected and addressed in batches through a central platform.