JWT Decoder Online

Created by:Dhiraj Reviewed by:Devglan Team

Decode a JSON Web Token (JWT) instantly to view its header and payload in a readable JSON format. Runs fully in your browser for secure debugging and token inspection. Supported JWT algorithms: HS256, HS384, HS512, RS256, RS512, PS256.

Explore our other set of JWT related tools:

  • HMAC (Shared Secret)
  • RSA (Public / Private Key)

Decode JWT Token Online

100% Client-Side Execution. No Data Sent to Server Secure

Decode a JSON Web Token to instantly view its header and payload. No secret or private key is required.

. .
Header Copy 

                                                        


                                                        

                                                            

                                                                Payload
                                                                Copy
                                                            

                                                            

                                                        


                                                        

                                                            
Signature

                                                            
                                                        

                                                        

                                                    


                                                    
                                                    
Header
                                                        Validation

                                                    
    
                                                        
                                                    


                                                    
                                                    
Claim Validation

                                                    
    
                                                        
                                                    


                                                


                                                

                                                    

                                                        Validate a JWT by verifying its signature and checking
                                                        registered
                                                        claims such as expiration and not-before.
                                                    

                                                    
                                                    
                                                    

                                                        

                                                            
                                                            
                                                        

                                                        
                                                    

                                                    

                                                        

                                                            

                                                            

                                                                
                                                            

                                                        


                                                        
                                                        

                                                            Required for RS* and PS* signature verification
                                                        

                                                    


                                                    

                                                        
                                                        

                                                    
                                                      ✔ Verified
                                                    
                                                        

                                                    


                                                    
                                                    

                                                        
                                                        
                                                        

                                                            Algorithm is detected from the JWT header
                                                        

                                                    


                                                    
                                                    

                                                        

                                                            
                                                            
                                                        

                                                        

                                                            
                                                            
                                                        

                                                    


                                                    
                                                    
    
                                                        
                                                    

                                                


                                                

                                                    

                                                        Generate a signed JWT using custom headers and claims for
                                                        testing
                                                        authentication and authorization flows.
                                                    

                                                    

                                                        

                                                            
                                                            
                                                        

                                                    


                                                    

                                                        
                                                        
                                                    

                                                    
                                                    

                                                        

                                                            
                                                            
                                                        


                                                        
                                                        

                                                            HMAC secret is only applicable for HS256 / HS384 / HS512
                                                        

                                                    

                                                    

                                                        

                                                            

                                                            

                                                                
                                                            

                                                        


                                                        
                                                        
                                                      Required to generate tokens using RS* and PS* algorithms
                                                    

                                                    


                                                    

                                                        

                                                            
                                                            

                                                                
                                                            

                                                        


                                                        
                                                        Optional - derived from private key, used for
                                                            verification
                                                    


                                                    
                                                    

                                                        
                                                        
                                                    

                                                    
                                                


                                            

                                        

                                    


                                    

                                    

                                        
                                        
                                        
                                    

                                

                                

                                    
All processing happens locally using the
                                        browser’s
                                        WebCrypto API. Your tokens and keys are never sent to any
                                        server,
                                        making this tool safe for debugging production JWTs.

                                    
What Is a JSON Web Token?

                                    

                                        A JSON Web Token (JWT) is a compact, URL-safe means of
                                        representing
                                        claims to be transferred between two parties.
                                        It consists of three parts: Header, Payload
                                        (claims), and Signature.
                                    

                                    
JWTs are widely used for API
                                        authentication, single sign-on (SSO), and securely
                                        transmitting
                                        information between client and server.
                                    

                                    

                                        A JWT consists of three parts separated by dots: the header, the payload, and
                                        the
                                        signature. While the signature ensures integrity, the header and payload can be
                                        decoded without verification.
                                    

                                    
How JWT Decoding Works

                                    

                                        JWT decoding converts the Base64URL-encoded header and payload into readable
                                        JSON.
                                        This allows developers to inspect token metadata and registered claims such as
                                        issuer,
                                        subject, and expiration time.
                                    


                                    

                                        Decoding does not verify token authenticity. To ensure a token has not been
                                        tampered
                                        with, signature verification should be performed using a
                                        JWT validator.
                                    

                                    
When Should You Use a JWT Decoder?

                                    
    
                                        
  • Debug authentication and authorization issues
    • 
                                        
  • Inspect JWT claims during API development
    • 
                                        
  • Understand tokens issued by identity providers
    • 
                                        
  • Verify token structure before signature validation
    • 
                                    

                                    
Is JWT Decoding Secure?

                                    

                                        JWT decoding is safe when performed in a trusted environment. This tool
                                        processes
                                        tokens entirely in your browser and does not transmit any data externally.
                                    

                                    

                                        For cryptographic validation, combine decoding with signature verification and
                                        encryption tools such as
                                        RSA encryption or
                                        ECC key verification.
                                    

                                    
Use Cases

                                    

                                        A JWT Decoder is commonly used during development and debugging to inspect the
                                        contents of a token without performing cryptographic verification.
                                    

                                    
    
                                        
  • Inspect JWT header and payload claims
    • 
                                        
  • Debug authentication and authorization issues
    • 
                                        
  • Understand tokens issued by identity providers
    • 
                                        
  • Verify token structure before validation
    • 
                                    

                                    
Security best-practice hints

                                    
    
                                        
  • Decoding a JWT does not guarantee it is valid - always verify the signature.
                                        
    • 
                                        
  • Do not trust sensitive claims unless the token is verified using RS256/RS512
                                            or PS256.
                                        
    • 
                                        
  • Keep your secrets and private keys secure - only share public keys for
                                            verification.
                                        
    • 
                                    

                                    
Tool Capabilities

                                    
    
                                        
  • Decodes Base64URL-encoded JWT header and payload
    • 
                                        
  • Displays claims in readable JSON format
    • 
                                        
  • Supports standard and custom JWT claims
    • 
                                        
  • Runs entirely in the browser with no server interaction
    • 
                                    

                                    
Key Terminologies

                                    
    
                                        
  • JWT - A compact token format used for secure information
                                            exchange
                                        
    • 
                                        
  • Header - Contains token type and signing algorithm
    • 
                                        
  • Payload - Stores registered and custom claims
    • 
                                        
  • Base64URL - Encoding format used by JWT components
    • 
                                    

                                    
Frequently Asked Questions (FAQ)


                                    

                                        
                                        

                                            A JWT decoder is a tool that converts a JSON Web Token into a readable JSON
                                            format
                                            by decoding its header and payload.
                                        

                                    


                                    

                                        
                                        

                                            Yes. Decoding a JWT does not require a secret key because the token is
                                            encoded, not encrypted.
                                        

                                    


                                    

                                        
                                        

                                            No. Decoding only reveals the token contents. Signature verification and
                                            claim checks
                                            are required to validate authenticity.
                                        

                                    


                                    

                                        
                                        

                                            It is safe if decoding is done locally. This JWT Decoder runs entirely in
                                            the browser
                                            and does not send data to any server.
                                        

                                    


                                    

                                        
                                        

                                            You can view the token header, payload claims such as issuer and expiration,
                                            and the
                                            algorithm used to sign the token.
                                        

                                    

                                    

                                        
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                                            new features.

                                        


                                            

                                                
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References