How to play Zip — a free, no-signup daily logic puzzle

Zip takes the one-line path puzzle that has become a morning fixture for millions of players and keeps it deliberately simple. There is a new board every day, shared by everyone, so you can compare times with friends. When the daily puzzle is done, an unlimited practice mode generates fresh, guaranteed-solvable grids whenever you want more — each one built and checked so that exactly one route works.

Three things set the tone. First, it is free — there is no paywall and no premium upsell. Second, it asks for no account: your streak and statistics live in your own browser, so you can start the moment the page loads without handing over an email address. Third, the interface is quiet — a clean board, a plain-text result you can copy, and zero emoji anywhere in the experience.

It is built to be read by everyone. The whole board renders before any script runs, so it works on a slow connection, and every cell is a real button you can reach with the arrow keys. A live text read-out tracks how many cells you have filled, your running time and whether the numbers are still in order — feedback that never depends on colour alone.

The day’s puzzle is the same for every player and rolls over at midnight in your own time zone. Solve it and your streak ticks up; come back tomorrow to keep it alive. When you finish you can copy a plain-text summary — your time, no spoilers — and paste it to friends. Because the board can be reasoned out rather than guessed, Zip rewards careful thinking over frantic tapping, and there is a Hint and a full Show solution for the days you get stuck.

The goal is to draw a single continuous line across a square grid. A handful of cells carry numbers; the rest are blank. Start on the cell marked 1 and extend the line one cell at a time until it has filled the whole grid. Three rules govern every move:

One line — the path is unbroken and never branches. It moves only between touching cells — up, down, left or right, never diagonally — and it may never cross itself or step back onto a cell it has already used.

In order — the line must reach the numbers in ascending sequence. It touches 1 first, then 2, then 3, and so on, with the highest number marking the end of the route. Arriving at a higher number before a lower one breaks the path, even if the rest of the grid would otherwise fill.

Every cell — when the line is finished it must pass through every cell of the grid exactly once. No cell is left blank, and none is visited twice. In the language of graph theory this route is a Hamiltonian path: a single trail that visits every square once.

Some boards add walls — short barriers drawn between two neighbouring cells. The line cannot cross a wall, so those two cells are simply not connected; treat a wall as a door that is locked. Between them, the ordered numbers and the walls constrain the grid so tightly that a well-formed Zip puzzle has exactly one solution, which means every move can be deduced rather than guessed.

On the board itself, tap a cell next to the end of the line to extend it. Tap the end of the line again to undo that step, or tap any earlier cell to retreat all the way back to it. Clear resets the line to the 1. You win the instant the line fills every cell with the numbers in order — the read-out switches to Complete and your time is locked in.

The trick to Zip is that the “fill every cell” rule quietly forces most of your moves for you. You rarely have to guess — you just have to notice which cells have no choice. Here is how that looks in practice.

Start in the corners. A corner cell touches only two others: the one to its side and the one above or below it. Because the line has to pass through that corner, it must both enter and leave — and with only two neighbours available, it is forced to use both of them. So the moment you see a corner, you already know two of the line’s segments there, before you have made a single choice.

Follow the degree-one cells. As the line grows, some empty cells end up with only one open neighbour — every other side is a wall, the grid edge, or a cell the line has already used. A cell like that has just one way in and one way out, so the connection to its single free neighbour is forced. Draw it in, and often that neighbour now has only one open side of its own, forcing the next segment too. One forced move cascades into the next.

Connect the numbers by the only route that fits. Say 1 sits in the top-left corner and 2 is two cells to its right, with the cell between them blank. The line has to get from 1 to 2 while still leaving room to fill everything else. Trace the shortest sensible path between them, then check the rule that decides everything: does taking it strand any cell — leave a square or a pocket of squares that the rest of the line can no longer reach? If a route would seal off a cell, it is wrong, and usually only one route survives that test.

Put those three habits together and a Zip board unravels like a zip fastener: fix the forced segments at the corners and dead ends, connect the numbers by the routes that keep every cell reachable, and the remaining blanks fall into place with almost no guessing at all.

LinkedIn popularised this one-line, hit-the-numbers-in-order path puzzle, and we are happy to say so plainly: Zip on duplixo is the same kind of game. This version is an independent clone, written from scratch with our own original code — the board, the path engine and the solver are all ours. What we have done is keep it free, make the practice mode unlimited and tidy up a few edges. The table below lays out the practical differences.

In practice the gap that matters most is what happens after you solve. With duplixo, finishing the daily puzzle is not the end — an unlimited practice mode generates fresh, verified boards on demand, so you can keep solving without any of it touching your daily streak. There is no “come back tomorrow” wall, and nothing to unlock with a subscription.