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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:

Online
(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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2 endpoints

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.

Live Demo

Live demo · no API key required
Query parameters
difficulty
width
height
seed

Get a free API key to get started — no credit card required.

Headers
X-Api-KeyLog in or sign up to get your API key
GET
https://api.api-ninjas.com/v1/sudokugenerate?difficulty=medium&width=3&height=3
Sample response
{
"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

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.

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.

Live Demo

Live demo · no API key required
Query parameters
puzzle
width
height

Get a free API key to get started — no credit card required.

Headers
X-Api-KeyLog in or sign up to get your API key
GET
https://api.api-ninjas.com/v1/sudokusolve
Sample response
{
"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
]
]
}

Code Examples

curl -X GET "https://api.api-ninjas.com/v1/sudokusolve?puzzle=%5B%5B0,0,0,2,6,0,7,0,1%5D,%5B6,8,0,0,7,0,0,9,0%5D,%5B1,9,0,0,0,4,5,0,0%5D,%5B8,2,0,1,0,0,0,4,0%5D,%5B0,0,4,6,0,2,9,0,0%5D,%5B0,5,0,0,0,3,0,2,8%5D,%5B0,0,9,3,0,0,0,7,4%5D,%5B0,4,0,0,5,0,0,3,6%5D,%5B7,0,3,0,1,8,0,0,0%5D%5D&width=3&height=3" \ -H "X-Api-Key: YOUR_API_KEY"

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.

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