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JWT decoder | agent view

The same page content and links, with explicit tool capabilities. Tools marked with an API can run directly through HTTP. Other tools require the browser interface or are not connected yet.

Tool capabilities

{
  "id": "jwt-decoder",
  "category": "developer-tools",
  "built": true,
  "requirements": "Decode header/payload locally; prominently distinguish decoding from signature verification.",
  "implementation": {
    "fields": [],
    "note": "Decoding does not verify the signature or establish trust. Tokens remain local.",
    "experience": {
      "automatic": true,
      "single": true,
      "label": "JWT",
      "placeholder": "eyJhbGciOiJub25lIn0.eyJzdWIiOiJleGFtcGxlIn0.",
      "help": "Paste all three dot-separated sections. Decoding does not verify the signature. Results update as you type. Up to 1,000,000 characters.",
      "action": null
    },
    "mode": "automatic",
    "interactive": false
  },
  "execution": "POST /api/v1/tools/jwt-decoder/run",
  "api": {
    "id": "jwt-decoder",
    "name": "JWT decoder",
    "category": "developer-tools",
    "description": "Decode header/payload locally.",
    "notes": "Decoding does not verify the signature or establish trust. Tokens remain local.",
    "human_path": "/en/developer-tools/jwt-decoder/",
    "method": "POST",
    "endpoint": "/api/v1/tools/jwt-decoder/run",
    "schema_url": "/api/v1/tools/jwt-decoder",
    "input_schema": {
      "type": "object",
      "additionalProperties": false,
      "properties": {
        "input": {
          "type": "string",
          "maxLength": 1000000,
          "default": "",
          "description": "Plain text input. File tools use files instead unless otherwise documented."
        },
        "options": {
          "type": "object",
          "additionalProperties": false,
          "properties": {}
        }
      }
    },
    "output_schema": {
      "type": "object",
      "required": [
        "tool",
        "result"
      ],
      "properties": {
        "tool": {
          "type": "string"
        },
        "result": {
          "type": "object",
          "required": [
            "text",
            "files"
          ],
          "properties": {
            "text": {
              "type": [
                "string",
                "null"
              ]
            },
            "data": {
              "description": "Parsed JSON when the textual result is JSON."
            },
            "name": {
              "type": "string"
            },
            "mime": {
              "type": "string"
            },
            "files": {
              "type": "array",
              "items": {
                "type": "object",
                "required": [
                  "name",
                  "mime",
                  "bytes",
                  "base64"
                ],
                "properties": {
                  "name": {
                    "type": "string"
                  },
                  "mime": {
                    "type": "string"
                  },
                  "bytes": {
                    "type": "integer"
                  },
                  "base64": {
                    "type": "string",
                    "contentEncoding": "base64"
                  }
                }
              }
            }
          }
        }
      }
    },
    "processing": "Server; same transformation code as browser tools",
    "limits": {
      "request_bytes": 8388608,
      "input_characters": 1000000,
      "files_bytes": 5242880,
      "max_files": 0,
      "timeout_seconds": 12
    }
  },
  "agent_processing": "Server; same transformation code as browser tools",
  "browser_agent": {
    "supported": true,
    "name": "run_current_tool",
    "discovery": "WebMCP on the human page in a supporting browser",
    "verification": "See audit/API-AUDIT.md; availability is not verification"
  }
}

Page guide

Decode header/payload locally.

Useful next steps

Base64 encoder decoder

Encode/decode tabs.

Unix timestamp converter

Seconds versus milliseconds, UTC/local zones and explicit out-of-range handling.

JSON formatter

Format and validate JSON in your browser.

How to use JWT decoder

  1. Enter jwt in the input field.
  2. The result updates as you type. Adjust the available settings if needed.
  3. Review the result, then use Copy result or a download link when available.

Working with jwt decoder

Formatting makes existing data or code easier to read. Validation checks whether it follows a syntax or schema. Conversion maps it into another representation. Choosing the right operation helps avoid treating a neatly formatted result as proof that the underlying data is correct.

Common questions

Does valid JSON mean the data is correct?

Syntax validation only establishes that the text can be parsed as JSON. A schema can check required fields and types, but neither proves that an email address, price or external record is factually correct.

Is decoding the same as decrypting or verifying?

No. Base64 and URL encoding are representations, not encryption. Reading a token payload does not verify its signature. Use the specific validation or verification process required by the system receiving the result.

Continue your workflow: Base64 encoder decoder, Unix timestamp converter, JSON formatter.