Use the tools to add constraints, then press SOLVE or GENERATE.
Add any combination of constraints to the grid, then press SOLVE — or press GENERATE to clear any non-given digits and generate a single-solution puzzle matching the given digits (blue) and constraints.
The Omnisolver is a sudoku construction tool. Add whatever combination of variant rules you like to the grid — killer cages, arrows, thermometers, kropki dots, between lines, clone regions, outside clues, jigsaw regions, and more — then either press SOLVE to check it yourself, or press GENERATE to have the computer systematically fill in a solution matching the grid constraints and attempt to reduce givens to the requested number while preserving solution uniqueness.
Pick a tool from the panel, then click cells on the grid. Most line/region tools (thermometers, arrows, cages, renban, between lines, clone regions) need a "Finish" click to commit — until then you can undo the last point or cancel the whole shape. Everything you've placed is listed in the "Placed constraints" panel below the grid, where you can remove individual pieces or clear a whole category at once.
Press GENERATE to open the options panel:
Any digit you've typed in yourself is always kept exactly where it is: generation builds its random solution around your typed-in digits and only ever removes/chooses cells elsewhere, so your own givens survive into the final puzzle untouched. It still only respects the constraint shapes you've drawn (a cage's cells, an arrow's path, and so on) beyond that — so the usual workflow is: type in any specific starting digits you want, draw your variant constraints, then generate. If your typed-in digits conflict with each other or with the drawn constraints, or if no valid solution containing them exists at all, generation reports that clearly instead of guessing at something else.
Your own typed-in givens are shown in bold blue, so you can always tell them apart from the bold black digits generation fills in on its own. Clear Solution removes only those generator-added digits (and any solve-preview overlay), leaving your blue givens exactly as you typed them; Clear All wipes everything, including your own givens and every constraint shape.
Every generated puzzle is rated 1 to 6, cheapest technique first, exactly the way a person solving on paper would build up their attack. Each level only requires that at least one technique from that tier was actually needed somewhere in the solve — using a tier-6 technique once is enough to make a puzzle 6 stars, regardless of how many easier steps also appeared elsewhere:
Every variant constraint on the grid (thermometers, kropki dots, between lines, clones, and so on) already shapes each cell's candidate list through the normal solving rules, so the star levels above benefit from those constraints automatically — there's no need for a technique that explicitly combines, say, an arrow and a kropki dot; each level just reacts to whatever candidates are left, however they got narrowed down. The ★★★★☆☆/★★★★★☆ patterns also respect variant adjacency (anti-knight, anti-king, diagonals, and so on) when checking which cells "see" each other.
This is a genuinely useful but not exhaustive rating: it will never wrongly rate a puzzle easier than it is, but it may occasionally call a puzzle "needs guessing" when a very sharp solver could in fact crack it with a technique outside this library (ALS, more exotic wing/chain patterns, and other advanced deductions aren't included). The forcing-chain checker is also deliberately conservative — it only follows short, two-branch chains built from singles, not arbitrarily long or complex ones — so a puzzle solvable by a longer forcing chain than that may still be reported as needing a guess.
Check For Conflicts looks at whatever's currently filled in and flags any broken rule without doing a full solve. SOLVE fills in a full solution as a preview, shown in regular-weight blue (not bold) so it's never confused with your bold blue givens — it doesn't touch your givens or commit anything to the grid, and pressing Clear Solution removes the preview. Export offers a JSON file (the only format that can be re-imported later) or a PNG/JPG image in color or a pure black-and-white print style.
WALKTHRU explains how to solve the grid currently on the board using logic alone, as a single numbered log of every placement and every supporting deduction, in true solving order. Placement entries name the cell and digit and explain every ruled-out alternative — either a direct conflict with a specific other cell (e.g. "already placed at R3C7, same column"), a reference back to the earlier numbered deduction that removed it, or (for a forcing-chain placement) the chain reasoning itself. Deduction entries (naked/hidden pairs, triples and quads, pointing pairs, box-line reduction, Skyscraper, X-Wing, Unique Rectangle, Swordfish, Jellyfish, finned/sashimi fish, XY-Wing, XYZ-Wing, Simple Coloring, cage/arrow sum-range checks) describe the pattern found and exactly which candidates it removed where, so nothing is left unexplained even for harder puzzles. It only works when the puzzle is fully solvable by the technique library described above; if it would need a guess anywhere, WALKTHRU says so instead of showing a partial or incorrect path. Open the result in a scrollable popup with Copy and Close buttons — Copy includes the full log, suitable for pasting into an answer key.