When was this TikTok job posted?
Paste a lifeattiktok.com URL and get back roughly when the posting went up. The date is hiding inside the ID.
TikTok job postings do not show a date. You get a listing and no idea whether it went up yesterday or eight months ago, which matters a lot when you are deciding where to spend an application.
The date turns out to be sitting in the URL.
https://lifeattiktok.com/search/7566369771879958789
^^^^^^^^^^^^^^^^^^^
The idea
That 19 digit number is not a counter. It is a 64 bit Snowflake style ID, the same shape Twitter used: a millisecond timestamp in the high bits, then a machine ID and a sequence number in the low 22 bits. Shift the ID right by 22 and the timestamp falls out.
[1 bit][ ~41 bit timestamp (ms) ][~10 bit machine][~12 bit sequence]
The problem
A Snowflake timestamp counts from a custom epoch, and ByteDance has never said what theirs is. So you can extract the number but you cannot turn it into a date.
The way around it is calibration. Take one posting whose publish time you actually know, treat it as a fixed point, and measure everything else against it:
ms_diff = (REFERENCE_ID - target_id) >> 22
target_time = REFERENCE_TIME - timedelta(milliseconds=ms_diff)
No epoch needed. You only ever need the distance between two IDs.
Does it work
Against itself, exactly. Against Google's "X days ago" labels it consistently reads older, sometimes by weeks. My read is that Google is showing first crawl time, and a posting that gets edited resets that clock, while the ID never moves. Day level accuracy is trustworthy. Minutes are not, and the 22 bit split is an assumption, not a documented fact.
It ships as a web page for one off lookups and a Python script that takes a list of IDs and prints them sorted by age.
What I learned
Opaque identifiers leak more than people expect. The interesting part was not the bit shifting, it was realizing that an unknown epoch does not matter if you only ever ask relative questions.