The URL is truncated after writing
A tag does not truncate a message, it refuses one that does not fit. So a shortened address means something else: the writing tool cut it, the reading display is abbreviating it, or you are reading a tag that was written earlier.
Tags refuse, they do not truncate
A write that exceeds the free space is rejected. The tag keeps its previous content and the tool reports a failure.
So a tag holding a shortened address did not lose the end during writing. Something shortened it before it reached the tag, or something is shortening it as you read it.
Establishing that first saves the entire investigation into capacity, which is the wrong place to look.
The display may be shortening it
Reading applications abbreviate long addresses to fit them on screen, sometimes with an ellipsis and sometimes by simply cutting.
The tag holds the full address and the screen shows part of it. This is the explanation more often than people expect.
Check by tapping the address to open it rather than reading it off the screen. If it goes where it should, nothing was truncated.
Or read the same tag with a second tool. Two tools showing different lengths tells you the difference is in the display.
The tool may have cut it
Some writing tools impose a field length limit, and pasting a long address into a short field silently drops the end.
This happens most with addresses carrying long query strings, which is exactly when a limit is reached.
Check what you typed rather than what you meant to type. A pasted address that looked complete in the clipboard may have been cut on entry.
Writing the address in two halves is not a workaround, since a record holds one address and appending produces a different one.
Confirming what is really there
Read the tag and copy the address out rather than reading it visually. Comparing text to text removes the display from the question.
Open it and see where it goes. That is the only test that matters to a visitor.
If the address is genuinely short on the tag, rewrite it with a tool that does not limit the field, and read back to confirm before deploying.
And consider a short address on your own domain instead. A short path avoids field limits, avoids capacity questions, and keeps the destination changeable.
Frequently asked questions
Can a tag hold half a URL?
Only if half a URL was written to it. The tag stores what it received and rejects a message too large rather than trimming one.
Why does my reader show an ellipsis?
Because the display is abbreviating a long address to fit the screen. Open it or copy it out to see the full value.
Does the prefix abbreviation cut the address?
No. It stores the common opening as a single byte and expands it on reading, so the address that comes back is complete.
Should I use a shortener?
Use your own domain instead. It saves the same bytes without adding a third party that can disappear and break every tag you deployed.