# HMAC generator

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

## Tool capabilities

| Property | Value |
| --- | --- |
| Tool ID | `hmac-generator` |
| Category | developer-tools |
| Implementation | Registered implementation. Registration alone is not a production-quality guarantee. |
| Browser execution | Use the visible action or interactive controls. |
| Browser processing | Browser; see tool notes for network behavior. |
| HTTP API | /api/v1/tools/hmac-generator/run |
| Browser-agent interface | run_current_tool |

### Implementation notes

HMAC-SHA-256. The secret stays in this tab.

### Inputs and settings

Text input: Your text.

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

```text
Type or paste your input…
```

Up to 1,000,000 characters. Review the settings before running.

| Setting | Meaning | Control type | Default | Constraints |
| --- | --- | --- | --- | --- |
| `key` | HMAC secret | password | "" |  |

### 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/hmac-generator/run
Content-Type: application/json
```

[Detailed operation reference](https://happytails.ai/en/api/tools/hmac-generator.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": {
        "key": {
          "type": "string",
          "description": "HMAC secret",
          "default": ""
        }
      }
    }
  }
}
```

#### 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

Local keys and data; algorithm selection and hex/Base64 output; no logging.

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

### Complete machine-readable capability record

```json
{
  "id": "hmac-generator",
  "category": "developer-tools",
  "built": true,
  "requirements": "Local keys and data; algorithm selection and hex/Base64 output; no logging.",
  "implementation": {
    "fields": [
      {
        "key": "key",
        "label": "HMAC secret",
        "value": "",
        "type": "password"
      }
    ],
    "note": "HMAC-SHA-256. The secret stays in this tab.",
    "experience": {
      "automatic": false,
      "single": false,
      "label": "Your text",
      "placeholder": "Type or paste your input…",
      "help": "Up to 1,000,000 characters. Review the settings before running.",
      "action": null
    },
    "mode": "explicit",
    "interactive": false
  },
  "execution": "POST /api/v1/tools/hmac-generator/run",
  "api": {
    "id": "hmac-generator",
    "name": "HMAC generator",
    "category": "developer-tools",
    "description": "Local keys and data.",
    "notes": "HMAC-SHA-256. The secret stays in this tab.",
    "human_path": "/en/developer-tools/hmac-generator/",
    "method": "POST",
    "endpoint": "/api/v1/tools/hmac-generator/run",
    "schema_url": "/api/v1/tools/hmac-generator",
    "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": {
            "key": {
              "type": "string",
              "description": "HMAC secret",
              "default": ""
            }
          }
        }
      }
    },
    "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

Local keys and data.

## Useful next steps

- [UUID generator](https://happytails.ai/en/developer-tools/uuid-generator/): Declare UUID versions, secure randomness for v4 and batch copy/export limits. ([Markdown](https://happytails.ai/en/developer-tools/uuid-generator.md))

- [File hash](https://happytails.ai/en/developer-tools/file-hash/): SHA-256 digest and compare expected value. ([Markdown](https://happytails.ai/en/developer-tools/file-hash.md))

- [Bcrypt generator](https://happytails.ai/en/developer-tools/bcrypt-generator/): Generate and verify locally with work-factor control. ([Markdown](https://happytails.ai/en/developer-tools/bcrypt-generator.md))

## How to use HMAC generator

1. Enter your text in the input field.
2. Review the settings, then choose Run HMAC generator.
3. Review the result, then use Copy result or a download link when available.

## Working with hmac generator

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: [UUID generator](https://happytails.ai/en/developer-tools/uuid-generator/), [File hash](https://happytails.ai/en/developer-tools/file-hash/), [Bcrypt generator](https://happytails.ai/en/developer-tools/bcrypt-generator/).