# JSON validator

- Human page: https://happytails.ai/en/developer-tools/json-validator/
- Markdown: https://happytails.ai/en/developer-tools/json-validator.md
- Structured JSON: https://happytails.ai/agents/en/developer-tools/json-validator/index.json
- Visibility: public

## Tool capabilities

| Property | Value |
| --- | --- |
| Tool ID | `json-validator` |
| Category | developer-tools |
| Implementation | Registered implementation. Registration alone is not a production-quality guarantee. |
| Browser execution | Automatic updates after valid input or file selection. |
| Browser processing | Browser; see tool notes for network behavior. |
| HTTP API | /api/v1/tools/json-validator/run |
| Browser-agent interface | run_current_tool |

### Inputs and settings

Text input: JSON.

Example or placeholder shown in the interface (not a validated fixture):

```text
{"name":"Ada","count":2}
```

Use double-quoted property names and valid JSON values. Results update as you type. Up to 1,000,000 characters.

| Setting | Meaning | Control type | Default | Constraints |
| --- | --- | --- | --- | --- |
| `indent` | Indent spaces | number | 2 |  |

### HTTP contract

API calls process supplied data on the server. The website origin is `https://happytails.ai`. Server API hosting is not connected on the public website yet. Use your local server origin to test these requests.

```http
POST https://happytails.ai/api/v1/tools/json-validator/run
Content-Type: application/json
```

[Detailed operation reference](https://happytails.ai/en/api/tools/json-validator.md) · [Shared API guide](https://happytails.ai/en/api.md)

#### Limits

| Limit | Value |
| --- | --- |
| request_bytes | 8388608 |
| input_characters | 1000000 |
| files_bytes | 5242880 |
| max_files | 0 |
| timeout_seconds | 12 |

#### Complete input schema

```json
{
  "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": {
        "indent": {
          "type": "number",
          "description": "Indent spaces",
          "default": 2.0
        }
      }
    }
  }
}
```

#### Complete output schema

```json
{
  "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"
              }
            }
          }
        }
      }
    }
  }
}
```

#### Error and retry handling

Failures return a non-200 status and `error.code` plus `error.message`. Correct invalid input before retrying; retry server-busy responses with bounded backoff. Returned files contain Base64 data, not persistent download URLs. Decode and inspect the output before treating conversion as successful. See the shared API guide for the complete status and timeout rules.

### Browser-agent workflow

1. Open the human page in a browser that supports WebMCP.
2. Discover the interface exposed by that page; use its actual schema.
3. Select files on the page first when the tool requires files.
4. Call `run_current_tool` with valid input and settings.
5. Inspect the returned result or error and the displayed output. Retrieve files from the displayed download links.

Calls do not automatically copy or download results. Browser permissions still apply. Interface availability alone is not proof of successful execution.

### Planning specification

Line/column errors and clear syntax-versus-schema validation scope.

This describes intended requirements. Use the implementation notes, interface schema and observed output to determine current support.

### Complete machine-readable capability record

```json
{
  "id": "json-validator",
  "category": "developer-tools",
  "built": true,
  "requirements": "Line/column errors and clear syntax-versus-schema validation scope.",
  "implementation": {
    "fields": [
      {
        "key": "indent",
        "label": "Indent spaces",
        "value": 2,
        "type": "number"
      }
    ],
    "experience": {
      "automatic": true,
      "single": false,
      "label": "JSON",
      "placeholder": "{\"name\":\"Ada\",\"count\":2}",
      "help": "Use double-quoted property names and valid JSON values. Results update as you type. Up to 1,000,000 characters.",
      "action": null
    },
    "mode": "automatic",
    "interactive": false
  },
  "execution": "POST /api/v1/tools/json-validator/run",
  "api": {
    "id": "json-validator",
    "name": "JSON validator",
    "category": "developer-tools",
    "description": "Line/column errors and clear syntax-versus-schema validation scope.",
    "notes": "",
    "human_path": "/en/developer-tools/json-validator/",
    "method": "POST",
    "endpoint": "/api/v1/tools/json-validator/run",
    "schema_url": "/api/v1/tools/json-validator",
    "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": {
            "indent": {
              "type": "number",
              "description": "Indent spaces",
              "default": 2.0
            }
          }
        }
      }
    },
    "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

Line/column errors and clear syntax-versus-schema validation scope..

## Useful next steps

- [JSON formatter](https://happytails.ai/en/developer-tools/json-formatter/): Format and validate JSON in your browser. ([Markdown](https://happytails.ai/en/developer-tools/json-formatter.md))

- [JSON to YAML](https://happytails.ai/en/data-tools/json-to-yaml/): Convert JSON to YAML. ([Markdown](https://happytails.ai/en/data-tools/json-to-yaml.md))

- [JSON to CSV](https://happytails.ai/en/data-tools/json-to-csv/): Convert JSON to CSV. ([Markdown](https://happytails.ai/en/data-tools/json-to-csv.md))

## How to use JSON validator

1. Enter json 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 json validator

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: [JSON formatter](https://happytails.ai/en/developer-tools/json-formatter/), [JSON to YAML](https://happytails.ai/en/data-tools/json-to-yaml/), [JSON to CSV](https://happytails.ai/en/data-tools/json-to-csv/).