.WEBLOC File Format – Contents

macOS website location

Apple does not publish a specification of .webloc itself. Sources for this page: Howard Oakley’s Data formats used in textClipping, webloc and mailloc files 1994–2025 (The Eclectic Light Company, 2025), and the Mozilla code Chromium carries for reading these files (third_party/mozilla/NSURL+Utils.m). In the newer form the file is an Apple property list whose root is a dictionary with a URL key; the property list formats are documented on their own pages.

Keys

KeyTypeValue
URLstringThe address as a string, such as https://example.com/.

Oakley describes .mailloc files the same way, and notes that Firefox has written .inetloc files of similar content; the Mozilla code reads .ftploc files with the same routine.

XML form

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>URL</key>
	<string>https://example.com/</string>
</dict>
</plist>

Binary form

The property list may also be binary; Oakley describes the newer data formats, introduced in about 2015, as binary property lists. Written by hand to the bplist00 layout, the same dictionary is 73 bytes:

00000000  62 70 6C 69 73 74 30 30 D1 01 02 53 55 52 4C 5F  bplist00...SURL_
00000010  10 14 68 74 74 70 73 3A 2F 2F 65 78 61 6D 70 6C  ..https://exampl
00000020  65 2E 63 6F 6D 2F 08 0B 0F 00 00 00 00 00 00 01  e.com/..........
00000030  01 00 00 00 00 00 00 00 03 00 00 00 00 00 00 00  ................
00000040  00 00 00 00 00 00 00 00 26                       ........&
A binary .webloc.
OffsetBytesMeaning
0x00bplist00Binary property list, version 00.
0x08D1 01 02Object 0: a dictionary of 1 pair; key is object 1, value is object 2.
0x0B53 55 52 4CObject 1: an ASCII string of 3 characters, URL.
0x0F5F 10 14 …Object 2: an ASCII string whose length (20) follows as an integer object, then https://example.com/.
0x2608 0B 0FOffset table: where objects 0, 1 and 2 start.
0x2932 bytesTrailer: 6 unused bytes, offset size 1, object reference size 1, 3 objects, top object 0, offset table at 0x26.

Resource fork form

The older form keeps the address in the file’s resource fork. Oakley: webloc and mailloc resource forks hold only a 'drag' resource (number 128) listing the others, and the URL as strings in both 'TEXT' and 'url ' resources; this form has been used since the last century and is still created. The Mozilla reader looks first for the 'url ' resource with ID 256 and falls back to the property list’s URL key. A file that loses its resource fork, for example on a disk without them, keeps only what is in its data fork.