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SEO & Performance

Cache-Control Explainer

Paste a Cache-Control header and instantly see what every directive means, how long the response stays fresh, and where the header contradicts itself. Your input never leaves the page.

Runs in your browser v1.0.0

1. Paste a header

no server

Paste the full Cache-Control: line or just the value. Multiple header lines are combined, commas and quoted lists are handled, and directive names are matched case-insensitively.

2. What it means

live

Normalized header 

                


                

                    
                    
                

            

        


        

            

                
Parsed directives

                0
            

            

                
    
            
    
        
    
    
    

    
    
        
    
            
    How it works
    
        
    
        
    
            
    
                The header is parsed in your browser with plain JavaScript. Directives are split on
                commas (respecting quoted field lists such as no-cache="Set-Cookie"),
                matched case-insensitively, and explained against the HTTP caching rules. Known
                mistakes — conflicting public and private,
                immutable without max-age, invalid durations, duplicate
                directives, request-only directives in a response — are reported as warnings
                instead of failing silently. Nothing is uploaded anywhere.
            
    
        
    
    
    

    

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