OpenAI API Request Checker

Statically inspect an OpenAI API request body for common JSON and parameter mistakes before sending it to the API.

This tool does not call the OpenAI API. It performs local static validation only. Always verify final requests against the official API documentation.
Request review 

        

    

                

            
                    

                        
How to use this tool

                        
    
                                                            
  1. Paste the request body JSON.
    2. 
                                                            
  2. Choose the model family you are targeting.
    3. 
                                                            
  3. Review errors, warnings and suggestions.
    4. 
                                                            
  4. Verify final behavior against the official API documentation.
    5. 
                                                    

                    


                    

                        
Common mistakes

                        
    
                                                            
  • Using max_tokens with model families that expect max_completion_tokens.
    • 
                                                            
  • Sending sampling parameters to reasoning models that do not support them.
    • 
                                                            
  • Using malformed response_format or tools arrays.
    • 
                                                    

                    


                    

                        
FAQ

                        

                                                            

                                    Does this call the OpenAI API?
                                    
No. It only performs local static validation in the browser.

                                

                                                            

                                    Is it a replacement for official docs?
                                    
No. It catches common mistakes, but final compatibility should be verified against official API documentation.

                                

                                                            

                                    Can I paste private prompts?
                                    
The checker runs locally, but you should still avoid pasting secrets into any web page unless you trust the environment.

                                

                                                    

                    


                        

        
Related tools

        

                                                
                        JSON
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Related guides and fixes

        

                                                
                        OpenAI
                        Debug OpenAI API Request JSON Before Sending
                        
Most API request bugs are easier to fix before the request is sent. Start with valid JSON, then check model-family parameters and only then debug application code.

                    
                                                                
                        cURL
                        cURL API Debugging Workflow for Developers
                        
cURL is the simplest way to separate API behavior from SDK, framework or frontend code. Build a minimal request first, then compare it with the failing implementation.

                    
                                                                            
                        OpenAI
                        OpenAI max_tokens vs max_completion_tokens Error
                        
This error usually appears when a request body mixes parameters from different OpenAI model families. Validate JSON first, then align token fields with the target model.

                    
                                                                
                        JSON
                        JSON Trailing Comma Error Fix
                        
JSON is stricter than JavaScript object literals. Trailing commas, comments and single-quoted strings can break API requests and config files.

                    
                                    

    

                        
Last updated: May 17, 2026