LinkedIn UGC Posts API: Missing Timezone Parameter for Scheduled Shares

Answer

The LinkedIn UGC posts /ugcPosts endpoint does not accept a timezone or offset field. The scheduledAt value must be an absolute UTC timestamp expressed in epoch milliseconds.

Confirmed Facts

• The request body contains only scheduledAt (UTC epoch ms); no timezone parameter is defined in the API spec.
• LinkedIn treats the supplied scheduledAt as an exact moment in UTC and does not adjust it based on the user's profile timezone or DST rules.

Likely Explanation

Because the API expects a UTC instant, any local‑time value sent without conversion will be interpreted as that same wall‑clock time in UTC, causing publishes to occur early or late depending on the offset. The service does not apply the author's profile timezone or historical DST transitions; it simply stores the provided UTC moment.

Recommended Workflow for Developers

1. Obtain the user's intended local datetime and timezone (e.g., using IANA tz database identifiers like "America/New_York").
2. Convert that local datetime to UTC epoch milliseconds with a reliable library (e.g., moment-timezone, date-fns-tz, or Java's ZonedDateTime).
3. Send the resulting UTC value as scheduledAt in the UGC posts request.
4. Optionally, verify the conversion by checking the offset for the date (e.g., ensure that a known DST transition date yields the expected UTC offset).

Verification Steps (optional)

• Schedule a test share for a known local time (e.g., 2026-11-05 10:00 America/New_York) after converting to UTC, then observe the actual publish time via the API or UI to confirm it matches the intended local moment.
• Attempt to include a custom field such as timezoneOffset in the request body; if the API ignores it or returns an error, this confirms that no timezone parameter is supported.