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Sudoku API

The Sudoku API allows you to generate and solve Sudoku puzzles of various sizes and difficulty levels.

Available endpoints:

(4.6)

From 9,384 users

900+

Applications using this API

API Status

Online - All Systems Operational

API Response Times

Average
P50
P75
P90
P95
280ms302ms321ms664ms1068ms

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/v1/sudokugenerate GET

https://api.api-ninjas.com/v1/sudokugenerate

Generate a new Sudoku puzzle with specified parameters.

Parameters

  • width  optional

    Width of each box in the Sudoku grid. Default is 3. Must be between 2 and 4.

  • height  optional

    Height of each box in the Sudoku grid. Default is 3. Must be between 2 and 4.

  • difficulty  optional

    Difficulty level of the puzzle. Possible values: easy, medium, hard. Default is medium.

  • seed  optional

    Seed value for reproducible puzzle generation.

Headers

  • X-Api-Key  required

    API Key associated with your account.

Response

A JSON object with the following fields or an error if the request is unsuccessful.

  • puzzle

    A 2D array representing the Sudoku puzzle grid. Empty cells are represented as null.

  • solution

    A 2D array representing the complete solution to the Sudoku puzzle.

Sample Request Live Demo!

difficulty
width
height
seed

Try our APIs in the API playground

Sign up for a free API key to get started — no credit card required.

https://api.api-ninjas.com/v1/sudokugenerate?difficulty=medium&width=3&height=3

Headers

X-Api-KeyLog in or sign up to get your API Key

Sample Response

JSON
{
    puzzle:[
      [
        4,
        null,
        8,
        null,
        7,
        3,
        null,
        null,
        9
      ],
      [
        null,
        6,
        9,
        null,
        4,
        2,
        null,
        8,
        7
      ],
      [
        2,
        null,
        null,
        null,
        5,
        null,
        null,
        4,
        6
      ],
      [
        6,
        7,
        3,
        null,
        1,
        null,
        null,
        9,
        null
      ],
      [
        9,
        2,
        4,
        null,
        6,
        null,
        null,
        null,
        8
      ],
      [
        null,
        null,
        5,
        2,
        9,
        null,
        6,
        7,
        3
      ],
      [
        3,
        null,
        2,
        9,
        null,
        1,
        null,
        null,
        5
      ],
      [
        null,
        null,
        null,
        null,
        null,
        null,
        null,
        null,
        null
      ],
      [
        null,
        5,
        null,
        null,
        3,
        6,
        9,
        2,
        null
      ]
    ],
    solution:[
      [
        4,
        1,
        8,
        6,
        7,
        3,
        2,
        5,
        9
      ],
      [
        5,
        6,
        9,
        1,
        4,
        2,
        3,
        8,
        7
      ],
      [
        2,
        3,
        7,
        8,
        5,
        9,
        1,
        4,
        6
      ],
      [
        6,
        7,
        3,
        5,
        1,
        8,
        4,
        9,
        2
      ],
      [
        9,
        2,
        4,
        3,
        6,
        7,
        5,
        1,
        8
      ],
      [
        1,
        8,
        5,
        2,
        9,
        4,
        6,
        7,
        3
      ],
      [
        3,
        4,
        2,
        9,
        8,
        1,
        7,
        6,
        5
      ],
      [
        7,
        9,
        6,
        4,
        2,
        5,
        8,
        3,
        1
      ],
      [
        8,
        5,
        1,
        7,
        3,
        6,
        9,
        2,
        4
      ]
    ]
}

Code Examples

1 2 curl -X GET "https://api.api-ninjas.com/v1/sudokugenerate?difficulty=easy" \ -H "X-Api-Key: YOUR_API_KEY"

If your programming language is not listed in the Code Example above, you can still make API calls by using a HTTP request library written in your programming language and following the above documentation.

/v1/sudokusolve GET

https://api.api-ninjas.com/v1/sudokusolve

Solve an existing Sudoku puzzle.

Parameters

  • puzzle  required

    2D JSON array representing the Sudoku puzzle. Use 0 for empty cells.

  • width  required

    Width of each box in the Sudoku grid. Must be between 2 and 4.

  • height  required

    Height of each box in the Sudoku grid. Must be between 2 and 4.

Headers

  • X-Api-Key  required

    API Key associated with your account.

  • Content-Type  required

    Must be set to application/json.

Response

A JSON object with the following fields or an error if the request is unsuccessful.

  • status

    The status of the solution attempt. Possible values: solved or unsolvable.

  • solution

    A 2D array representing the solved Sudoku puzzle. Only present if status is solved.

Sample Request

puzzle
width
height

Try our APIs in the API playground

Sign up for a free API key to get started — no credit card required.

https://api.api-ninjas.com/v1/sudokusolve

Headers

X-Api-KeyLog in or sign up to get your API Key

Sample Response

JSON
{
    status:"solved",
    solution:[
      [
        4,
        3,
        5,
        2,
        6,
        9,
        7,
        8,
        1
      ],
      [
        6,
        8,
        2,
        5,
        7,
        1,
        4,
        9,
        3
      ],
      [
        1,
        9,
        7,
        8,
        3,
        4,
        5,
        6,
        2
      ],
      [
        8,
        2,
        6,
        1,
        9,
        5,
        3,
        4,
        7
      ],
      [
        3,
        7,
        4,
        6,
        8,
        2,
        9,
        1,
        5
      ],
      [
        9,
        5,
        1,
        7,
        4,
        3,
        6,
        2,
        8
      ],
      [
        5,
        1,
        9,
        3,
        2,
        6,
        8,
        7,
        4
      ],
      [
        2,
        4,
        8,
        9,
        5,
        7,
        1,
        3,
        6
      ],
      [
        7,
        6,
        3,
        4,
        1,
        8,
        2,
        5,
        9
      ]
    ]
}

Frequently Asked Questions

  • Yes, but you must have a premium subscription. Commercial use of the Sudoku API is not permitted on the free tier. See our pricing page to choose a plan that fits your needs.
  • Sign up for a free account to instantly get your API key, then pass it in the X-Api-Key header on every request. The documentation above includes ready-to-run examples in cURL, Python, JavaScript, Node.js, and more.
  • Your API requests will simply be denied once you hit your monthly quota — you will never be charged more than the plan you signed up for. To increase your quota, you can upgrade your plan any time on our pricing page.
  • The API responds with a standard HTTP status code and a JSON error message describing the problem. See our error codes reference for the full list of codes and how to resolve each one, or contact support if you need help.
  • The Sudoku API has two endpoints: /v1/sudokugenerate creates a brand-new puzzle with both a puzzle grid and its solution, while /v1/sudokusolve takes an existing puzzle you supply and returns its solution. Both are GET requests authenticated with your API key from your account.
  • On /v1/sudokugenerate, use the difficulty parameter (easy, medium, or hard, defaulting to medium) and the width and height parameters to set each box's dimensions, both defaulting to 3 and accepting values between 2 and 4. You can also pass a seed value for reproducible puzzle generation. See pricing for request volume options.
  • Call /v1/sudokusolve with a required puzzle parameter (a 2D JSON array using 0 for empty cells) plus the matching width and height of each box; the response returns a status of solved or unsolvable, and a solution 2D array when solved. If something goes wrong, consult the error codes.
  • You can use it to power puzzle apps, daily challenge games, or printable worksheets by generating puzzles via /v1/sudokugenerate, and to validate or auto-complete user-entered grids via /v1/sudokusolve. For more puzzle and quiz content, pair it with the Riddles API, Trivia API, or Facts API.