ZPL viewer, online
Paste the ZPL and see the label drawn the way a printer would draw it, before you print.
Why a ZPL file will not open on its own
The file is text, not an image: it describes how to draw the label, and the printer is what draws it. Without one that speaks ZPL, double-clicking shows nothing, and Notepad shows the code instead of the result.
A viewer plays the printer's part: it reads the same file and draws on screen what would come out on paper.
What you see here is what the printer would draw
Same commands, same measurements, same density. It is not an approximation of the format: every version of the drawing is compared pixel for pixel against reference images kept in the project, and an update that changes how a label is drawn shows up before it reaches you.
Two things change the result and are worth checking. Density, which has to match your printer, and label size, which has to match the stock you use. Getting either wrong shifts everything.
Look, and take it with you
The label is drawn shortly after you stop typing, with nothing to click. If the file holds several, the arrows move between them, and the download button hands you the image on screen.
When what you want is the whole batch ready to print, the converter is what does that: a PDF with one page per label, carrying the physical size so the print comes out at the right measurements. The link to it is right here.
Nothing you open is kept
The file is processed and discarded. Neither the ZPL, nor the images, nor the file name ends up on disk, in a database or in a log.
A shipping label carries the recipient's name, address and national ID. Keeping that would bring the product no benefit and would put at risk people who do not even know their data passed through here.