- 1 Identify what you actually copied
JSON starts with
[or{. Netscape is tab-separated TRUE/FALSE columns, often with# Netscape HTTP Cookie File. Headers look likename=value; name=value. Set-Cookie lines start with that token or includeDomain=. - 2 Paste only the cookie payload here
Strip surrounding logs, HAR JSON, email wrappers. If the status still says unknown, try Base64 decode or repair spaces in Netscape. The converter reports the detected format when it works.
- 3 Use the rewritten output
Copy JSON for CookieMan Import, or Netscape for curl. Do not paste the original log back into Import.
Message → cause → fix
| Message | Cause | Fix |
|---|---|---|
Could not detect cookie format. Supported: JSON, Netscape, Header, Set-Cookie, Base64 | No detector returned cookies | Paste one supported format only |
Empty input | Whitespace-only | Paste the file |
Invalid Base64 payload | Alphabet / padding | Not Base64 — try raw JSON |
Decoded Base64 content is not a recognized cookie format | Inner text is unrelated | Decode offline and inspect |
Expected JSON array / parse throw | Forced JSON that is not an array | Use auto-detect, or wrap as [...] |
| UTF-8 BOM on JSON (older tools) | JSON.parse threw on \uFEFF | Already stripped in this detector |
Detection order: JSON (including a
cookies wrapper) first, then Base64, Netscape, Set-Cookie, JSON map, header. A file that is “almost Netscape” but uses spaces is repaired — Skipped invalid Netscape line. Files that will never detect
- Full HAR / Postman collection / Charles session documents.
- SQLite
cookies.sqlite(Firefox) or Chrome’s binary Cookies DB. - CSV exports with arbitrary columns.
- Prose (“here are my cookies: session_id is abc123”).