Does re-importing exported LeetCode submission timestamps preserve original dates or are they treated as new submissions?

Direct answer

Re‑importing a LeetCode submission from exported JSON does not preserve the original timestamp. The platform treats the re‑submitted code as a brand‑new entry, stamping it with the current server time.

Confirmed facts

• The Export Data feature in Account Settings generates a read‑only JSON archive of submission history, including timestamps, language, code snippets and verdicts. It is not a restorable backup format that LeetCode can ingest.
• Submissions are server‑side records; the timestamp is assigned at the moment the judge accepts the request. The web editor and documented submission flow do not accept a client‑supplied historical timestamp.
• Streak counters, activity heatmaps and badge logic are computed from submission dates. A re‑submitted solution counts as activity on the day it was re‑submitted, so historical gaps are not backfilled and prior streaks are not restored.
• LeetCode does not deduplicate identical code. Submitting the same accepted solution again creates a separate submission record with its own verdict, runtime and timestamp.
• Contest ratings are derived from submissions within a contest’s active window. Re‑submitting a saved solution after the contest ends is a normal practice submission and does not retroactively alter past contest results or rating history.

Likely explanation

Because the export is an archival snapshot and the platform’s submission pipeline timestamps events server‑side, any re‑uploaded code inherits the current time. The original timestamp fields in the JSON remain useful as personal records or for third‑party analytics that read the file directly, but they have no effect on platform‑side metrics.

Verification (scoped steps)

1. Export your data from LeetCode Account Settings and locate the timestamp field for a specific submission in the resulting JSON.
2. Manually re‑submit the same code via the web editor.
3. Open the submissions page and check the timestamp of the new entry; it should match the current date, not the original JSON timestamp.
4. Compare the streak and heatmap state before and after the re‑submission on a quiet day; the re‑submission day gains activity while earlier gaps remain unchanged.

Note: LeetCode's export format and streak logic are undocumented and may change across platform updates; the behavior described reflects generally observed patterns as of 2026.