Interactive Sudoku Solver (ISS)

To set a value, select a cell and type a number.

To add a line or region constraint, select and drag; or shift-click.

To add a Little Killer constraint, select a diagonal arrow outside the grid.

To add other outside clue constraints, select a row or column arrow outside the grid.

OR (Source)
OR
Auto-solve

Stats by runtime

Constraints

Set multiple values

Lines & Sets

Select cells by dragging or shift-clicking.

Shape

Global constraints

Layout constraints

Custom binary constraints

Create a constraint between two cells by providing a custom JavaScript function.

The function takes the two cell values as input and should return true or false to indicate if the pair of values is valid.

Example: a < b will emulate a thermometer constraint.

Name:
Chain handling :
Constraint: (a,b) =>

Outside clues

Select a row, column or diagonal arrow outside the grid.

Composite constraints (experimental)

Select a composite constraint by clicking on its chip to add constraints to it. Panels which allow constraints to be added to the composite will be highlighted in yellow.